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1
Elyasi, Siamak. "Developmemt of UV photoreactor models for water treatment." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/15251.
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Ultraviolet (UV) reactors are promising for the future of drinking water and wastewater treatment technology. Models simulating the performance of UV reactors enhance our understanding of the fundamental principles governing the operation of these units. When modeling the performance of UV reactors, governing equations for all related phenomena are derived and solved. The theoretical models and experimental approaches for evaluating the results of these models are comprehensively reviewed and presented in this research. The thesis presents a step-by-step methodology for solving the governing equations of UV reactors.
This research presents a general method that integrates the Fresnell, Snell, and Beer-Lambert laws for modeling the radiant distribution in a medium. The model uses the boundary conditions to realistically simulate the fluence/irradiance rate around the radiant source, in particular, in the zone closest to the radiant source. Different low-pressure UV lamps were tested under different operating conditions using photodiodes and a radiometer. The experimentally measured irradiance rate is in excellent agreement with the results of the simulation.
Conventionally, the performance of a UV reactor is evaluated using the concentration of photoreactive chemicals at the outlet vs. the inlet. This research presents a novel method for measuring the concentration distribution of a photoreactive chemical inside a photoreactor using a modified planar laser-induced fluorescence method. The fluence distribution was measured for a pilot scale photoreactor under different operating conditions. The visualized result of the fluence distribution revealed significant information about the local/overall performance of the photoreactor. This method is a powerful diagnostic tool for the determination of the local performance inside a UV reactor, as well as for the evaluation of models simulating UV reactor behavior.
A computational fluid dynamic (CFD) model was developed in order to simulate UV photoreactors in the Eulerian framework for microbial disinfection and chemical removal using a UV-based hydroxyl radical initiated oxidation process. The integrated CFD model of UV photoreactor performance was successfully validated by comparisons with experimental results. This verified procedure can be applied to the simulation and optimization of UV photoreactors with different geometries and operating conditions.
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Bridgeforth, Sharonda E. (Sharonda Elaine) 1975. "Groundwater treatment technologies : air stripping vs. UV/oxidation." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/49999.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Includes bibliographical references (leaves 57-58).
by Sharonda E. Bridgeforth.
M.Eng.
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Nguo, Manases Fuh. "TREATMENT OF ODOROUS VOLATILE ORGANIC COMPOUNDS USING UV/H2O2." Thesis, KTH, Energiprocesser, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90432.
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Odorous volatile organic compounds emissions from fried-food industries posed severed pollution problems both to the workers and the surrounding inhabitants. These industries need to look for cost effective and efficient methods to reduce these emitted gases. Several solutions such as the use of centrifugation, scrubbers, ion exchangers, biofiltration, condensation, adsorption, absorption, and incineration have been exploited to reduce these smelling gases. Centriair in collaboration with KTH aim at using UV light in combination with ozone and hydrogen peroxide to degrade these odorous VOCs emitted from the frying of meat balls (SCAN) and chips. Several volatile organic compounds which are odorants with low threshold values were identified in the emitted gases from meat frying which includes: aldehydes, sulphur containing compounds, ketones, pyrazines, and alcohols. The type and concentration of these odorants emitted depends among other things primarily on the type of oil used during the frying process. This work focuses on the use of advanced oxidation processes to abate theses odorous gases. The effect of UV dosage and the use of hydrogen peroxide were tested in a flow reactor. Ozone producing UV lamps were used for the treatment of 2,4-decadienal, Hexanal, furfural, and 2,5-dimethylpyrazine. A simultaneous chemical and odour analysis was done using a GC/MS Olfactometry system. UV/Ozone/H2O2 was effective in reducing the volatile organic compounds tested thus reducing the odor concentration. The percent removal was proportional to the energy dosage.
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Howell, Anne C. "Effects of antioxidant vitamin treatment on UV-irradiated cells." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/941360.
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Ultraviolet (UV) radiation damages both eukaryotic and prokaryotic cells by causing the formation of free radicals which damage cell membranes and DNA. Antioxidant vitamins have been shown to protect cells from UV-induced damage by scavenging free radicals. The protection of skin and its normal flora is necessary for the health of individuals in resisting diseases caused by microorganisms and delaying the long-term damage caused by UV radiation.This research investigated the effects of the antioxidants vitamin A and ascorbic acid, as well as UV-irradiation on both prokaryotic (Staphylococcus epidermidis) cells and eukaryotic (human fibroblast skin) cells. This information is important in determining the effects of vitamin treatment on skin and its normal flora.Results indicate that ascorbic acid is rapidly (within six hours) degraded after being dissolved in water or medium. Treatment of cells with ascorbic acid must take into account this rapid degradation. S.epidermidis cells were protected from UV-induced damage by treatment with ascorbic acid but were more sensitive to UV-irradiation when treated with vitamin A. Human fibroblast cells treated with ascorbic acid did not exhibit morphological changes when compared to untreated cells.Department of Biology
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Chintalapati, Pranav Sankar. "Degradation of cyanobacterial toxin microcystin-LR using UV/vacuum-UV advanced oxidation for drinking water treatment." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63028.
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Cyanobacterial blooms have been increasing in magnitude and frequency around the world and studies have concluded that climate change, population growth, and industrial development will accelerate this phenomenon. The presence of cyanobacterial blooms in drinking water sources is a concern due to the production of cyanobacterial toxins, which are known to damage internal organs and disrupt nervous system functions. Shallow surface water sources for small water systems are at a greater risk of eutrophication and small, remote communities often lack the resources and infrastructure for adequate treatment. In conventional water systems, instances of cyanobacterial blooms are typically addressed by chemical addition. However, many remote communities are difficult to access and are unable to maintain a consistent supply of chemical oxidants.
This study investigated the capability of ultraviolet radiation at 254 nm and 185 nm wavelengths (UV/Vacuum-UV) to degrade microcystin-LR (MC-LR), one of the most commonly occurring and toxic cyanobacterial toxins. Results showed that substantial toxin removal could be achieved solely by direct photolysis with 254 nm. The addition of 185 nm increased MC-LR degradation through advanced oxidation by hydroxyl radicals (•OH). The presence of alkalinity and organic matter (DOC) reduced MC-LR degradation by scavenging •OH. DOC also absorbed 254 nm and 185 nm, requiring additional irradiation time to achieve a target UV dose. Chloride scavenged •OH, but in a reversible reaction, resulting in minimal impact on MC-LR degradation. The order of impact on MC-LR degradation by these common water constituents was DOC>Alkalinity>Chloride. In natural water with a complex matrix, MC-LR could be degraded from a typical concentration (15 µg/L) to below detection (<0.5 µg/L) with a UV254 fluence of 200 mJ/cm2. The presence of cyanobacterial cells impeded MC-LR degradation by adding turbidity to samples, absorbing 254 nm photons and scavenging •OH. However, substantial MC-LR degradation could still be achieved in the presence of cyanobacterial cells. UV/Vacuum-UV appears to be a promising chemical-free technology that is capable of MC-LR degradation in a variety of water conditions, and may be a suitable treatment option for small, remote communities.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Van, Huu Tap, Van Tuyen Trinh, and Xuan Hien Dang. "Treatment of leachate by combining PAC and UV/O3 processes." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-99370.
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The landfill leachate is commonly treated for non-biodegradable organic matters, ammonia and colour. Experimental investigations using polyaluminium chlorite (PAC) and UV/O3 have been conducted for the determination of optimal pH value, reaction time and PAC concentration for the removal of chemical oxygen demand (COD) and colour. In pre-treatment coagulation stages, the highest COD and colour removal efficiencies were observed at the concentration of PAC ≥ 3,000 mglG1 and pH values between 7 and 8. However, these experiments also indicated significant removal efficiency for PAC starting with concentrations of 1,500 mglG1. The efficiency of COD and colour removal were approximately 30% and 70%, respectively. Similar efficiencies have been observed also during the second treatment stage where UV/O3 processes were used to treat coagulated leachate. After UV/O3 application, the pH of leachate reached the optimum value of 7.5 whereas the highest COD and colour removal efficiency was 55% and 72%, respectively, and the optimal reaction time was achieved after 80 minNước rỉ rác sinh ra từ bãi chôn lấp chất thải rắn cần được xử lý các thành phần chất hữu cơ khó phân hủy sinh học, xử lí amoni và độ màu. Một số kết quả thử nghiệm về xử lý COD và màu của nước rỉ rác bằng việc sử dụng phương pháp keo tụ với PAC và quá trình UV/O3 đã được thực hiện cùng với việc xác định các giá trị pH tối ưu, thời gian phản ứng và nồng độ PAC tối ưu. Hiệu suất xử lý cao nhất đạt được khi nồng độ của PAC ≥ 3.000 mg/l, pH trong khoảng từ 7 đển 8 trong giai đoạn tiền xử lý. Tuy nhiên, hiệu quả loại bỏ COD và màu bắt đầu tăng rõ khi nồng độ PAC từ 1.500 mg/l trở lên. Hiệu quả loại bỏ COD và màu tương ứng là khoảng 30% và 70%. Các giá trị pH này phù hợp cho quá trình phản ứng UV/O3 được sử dụng sau giai đoạn keo tụ. Sau quá trình xử lý bằng hệ UV/O3, pH của nước rỉ rác tối ưu được xác định là 7,5 (hiệu suất xử lý COD và màu cao nhất tương ứng là 55% và 72%), thời gian phản ứng tối ưu là 80 phút
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Gao, Jiong. "UV/Sodium Percarbonate for Treatment of Bisphenol A in Water." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin161710940946631.
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Obande, Matthew A. "Effect of preharvest UV-treatment on shelf life of fruits and vegetables." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/7768.
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The benefits of low UV dose treatment of horticultural produce – also known as hormetic treatment - have been attested to in numerous studies conducted over the last 15 years. However, commercial growers have not adopted the concept of hormesis. With increasingly stringent controls on the use of fungicides and other chemical agents the time has come to examine how hormetic treatment might be applied in the horticulture sector. The objectives of this work were firstly, to confirm UV-induced hormetic effects applied postharvest for a number of different types of produce, namely, tomatoes, broccoli, strawberries and mangoes. Secondly, to evaluate the use of rollers to ensure full surface treatment of produce, and thirdly to evaluate the possibility of treating produce preharvest. In order to investigate surface UV dose distributions, a polystyrene sphere (Diameter 70 mm) was used to simulate fruits such as tomatoes, apples, peaches etc., that have an approximately spherical form. Biodosimetry based on spores of Bacillus subtilis was employed to experimentally determine UV doses and to compare the results obtained with theoretical predictions. Good agreement was obtained and the modelling approach was extended to other types of produce. This showed the amenability of mechanical rollers to ensure full surface treatment of produce. Postharvest treatment of produce was carried using conventional low intensity UV sources principally emitting at 254 nm and also a commercially available high energy pulsed UV source. Treatment using the conventional UV source was carried out on mechanical rollers within a UV cabinet designed for this work at a fixed distance from the source and at an intensity of 1000 μW/cm2. A 5 minute conventional UV treatment of tomatoes was approximately comparable to fruit given a 3-pulsed treatment using the pulsed source (507 J/pulse of polychromatic light). The colour and texture of both groups of fruit were significantly maintained as compared with controls. The treated tomatoes also showed a significant increase in the ascorbic acid levels during storage. Similarly, a 15 minute conventional UV treatment of broccoli heads was comparable to heads given a 10-pulsed treatment using the pulsed source. Where both treatments gave rise to a statistically significant retention of green colour of treated broccoli. In addition, mangoes given a 10 minute conventional UV treatment were comparable to fruit given a 20-pulsed treatment using the pulsed source with both treatments leading to maintenance of texture as compared to control fruit. This confirmed the UV-hormetic effects. The effects of conventional and pulsed treatments are compared and discussed. Preharvest treatment of tomatoes and strawberries was carried out in commercial glasshouses. Doses of either 3 or 8 kJ/m2 were delivered to the fruits using a treatment device designed for the work, which delivered a combined intensity of 2000 μW/cm2 from two low pressure UV sources. The treated tomatoes showed a delay in development of colour as measured on the vine and after picking. Picked tomatoes were inoculated with P. digitatum and C. gloeosporioides and the results obtained showed a significant inhibition of the development of the fungi in the treated fruit during the storage period. These results suggest that the beneficial response shown by the preharvest treatment is not a localised one but a systematically induced resistance observable throughout the treated plant. This was shown by monitoring tomato fruits on treated plants which themselves where not directly exposed to the UV light. The two doses elicited different responses in the treated strawberries, with the 8 kJ/m2 dose causing the fruit to redden significantly faster than the 3 kJ/m2 treated fruits and controls. This could have significant nutritional benefit as the red colour of strawberries has been correlated with anthocyanin levels. On the other hand, treatment at the lower UV dose led to a lag in colour development. The amenability of the equipment utilised for commercial application is discussed.
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Huang, Ying. "Applications of UV/H2O2, UV/NO3–, and UV-vis/ferrite/sulfite Advanced Oxidation Processes to Remove Contaminants of Emerging Concern for Wastewater Treatment." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535703890003601.
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GONCALVES, ADRIANA CINOPOLI. "TREATMENT OF EFFLUENTS CONTAINING FREE CYANIDE THROUGH THE SYSTEM H2O2/UV." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6043@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOO presente trabalho teve como objetivo estudar o tratamento de efluentes contendo cianeto livre através do sistema H2O2/UV e selecionar as condições operacionais mais adequadas para uma maior eficiência do processo. Para isso, foram empregadas soluções sintéticas de KCN com características de pH e concentração similares às condições de um efluente industrial real. O fotorreator utilizado nos testes de oxidação foi um reator cilíndrico de seção anular, equipado com uma lâmpada de baixa pressão de 28 W concêntrica com emissão em 254 nm, onde a solução ficava diretamente em contato com a mesma. Este fotorreator foi acoplado a um sistema de refrigeração que mantinha a temperatura de operação em 25oC.As variáveis avaliadas foram concentração inicial de cianeto em solução, pH inicial da solução, potência de UV irradiada e razão molar [H2O2]/[CN-]. Para soluções contendo uma concentração inicial de cianeto igual a 100 ppm, foi possível atingir uma eficiência remoção de 99,9 por cento em 25 minutos, em pH igual a 9,5, com uma razão molar [H2O2]:[CN-] igual a 3. Para efluentes contendo uma concentração inicial de cianeto igual a 300 ppm, nas mesmas condições operacionais, alcançou-se a mesma eficiência em 30 minutos.
The present work had the objective of studying the treatment of effluents containing free cyanide through the system H2O2/UV, and of selecting the best operational conditions for best efficiency of the process. For that, it was employed synthetic solutions of KCN with characteristics of pH and concentration similar to those of a real effluent. The photoreactor employed in the oxidation tests was a cylindrical reactor of annular section, equipped with a concentrical low pressure lamp of 28 W with emission in 254 nm, where the solution was in direct contact with the lamp. This photoreactor was coupled with a cooling system which kept the operation temperature at 25oC. The evaluated variables were initial cyanide concentration in solution, initial pH of the solution, power of radiated UV and molar ratio [H2O2]/[CN-]. For solutions containing an initial concentration of cyanide equal to 100 ppm, it was possible to reach a removal efficiency of 99.9 per cent in 25 minutes, in pH equal to 9.5, with a molar ratio of [H2O2]:[CN-] equal to 3. For effluents containing an initial concentration of cyanide equal to 300 ppm, at the same operational conditions, it was possible to achieve the same removal efficiency in 30 minutes.
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Serrano, Mora Adrian. "UV/Vacuum-UV Advanced Oxidation Process for the treatment of micropollutants from drinking water sources under common operational temperatures." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57667.
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Vacuum-UV Advanced Oxidation Process (AOP) has been identified as a viable candidate to treat chemical contaminants in drinking water. In contrast to the commercially available and widely applied UV/H₂O₂ AOP, VUV AOP does not rely on the addition of chemicals for the generation of hydroxyl radicals. As a result, the technology is very appealing to small systems and rural communities which often lack infrastructure and qualified personnel to operate complex systems.
The primary objective of this research was to investigate the effect of temperature on the removal efficiency and energy consumption of a UV/VUV flow-through photoreactor. Additionally, the optical absorption properties at 185 nm of water and naturally occurring solutes such as Natural Organic Matter (NOM), nitrate, sulphate and chloride were studied between 3.6 and 25.0 °C. The secondary objective of this research was to investigate the effect of UV/VUV treatment on the removal of a mixture of micropollutants (e.g., pharmaceuticals, hormones, pesticides).
The results showed that temperature does not have a significant impact on process efficiency and energy consumption. Moreover, owing to the presence of naturally occurring solutes, it was found that the production of OH radicals was to some extent limited at 3.6 °C, therefore slightly lower removals were observed at low temperature. When evaluated on a mixture of micropollutants, the UV/VUV process could potentially degrade a variety of substances with feasible energy consumption. Other than for two of the 12 micropollutants tested, at a flow-rate of 1.9 L min-¹, the VUV process was competitive to the UV/H₂O₂ process.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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McGivney, Eric. "Comparison of UV-C and Vacuum- UV induced AOT on the acute mortality of microalgae." Thesis, KTH, Mark- och vattenteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171839.
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Advanced oxidation technology (AOT) has been used to destroy microorganisms in ballast water by breaking down the cell membranes. The primary objective of this study was to determine the effects of a ballast water treatment system that uses a combination of UV-C (λ=254 nm), Vacuum-UV (VUV; λ=185 nm) and photocatalytic titanium dioxide (TiO2) on a freshwater algae, Pseudokirchneriella subcapitata, and a marine algae, Tetraselmis suecica. The coupling of a semiconductor, such as TiO2, with a UV source is known as an advanced oxidative technology (AOT). To test the effects of TiO2 and wave length on algae, dose-response experiments were conducted to determine the species median lethal dose (LC50) for each of the following treatments: UV-light emitted at 254 nm (UVλ=254 nm), UV-light emitted at 254 nm in the presence of TiO2 (AOTλ=254 nm), and UV-light emitted at λ=254 nm (90 %) and 185 nm (90 %) in the presence of TiO2 (AOTλ=185 + 254 nm). In both species, TiO2 significantly increased mortality, most likely due to the biologically harmful radicals generated at the TiO2 surface. The addition of the 185 nm wavelength significantly increased cell mortality in P. subcapitata, but not in T. suecica. Across all three treatments, P. subcapitata was more sensitive than T. suecica. The secondary purpose of this study was to assess the applicability of ImageJ, an image analysis software, for highthroughput data to analyze the effectiveness of ballast water treatment. ImageJ has been used to rapidly and accurately perform cell Live/Dead analysis; however, several hurdles were identified.
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LIU, XIAOXIAO. "UV Laser Treatment of Tire Reinforcing Materials for Improved Adhesion to Rubber." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1445884367.
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Hua, Fang. "The effects of water treatment works on chlorine decay and THM formation." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364492.
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Cheung, Chi-shing, and 張志成. "Economic valuation of UV disinfection in Hong Kong sewage." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31255802.
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Alvarez, Corena Jose Ricardo. "Heterogeneous Photocatalysis For The Treatment Of Contaminants Of Emerging Concern In Water." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-dissertations/320.
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"The simultaneous degradation of five organic contaminants: 1,4 dioxane, n-nitrosodimethylamine, tris-2-chloroethyl phosphate, gemfibrozil, and 17β estradiol, was investigated using a 1 L batch water-jacketed UV photoreactor utilizing titanium dioxide (TiO2) nanoparticles (Degussa P-25) as a photocatalyst. The primary objectives of this research were: (1) to experimentally assess the feasibility of heterogeneous photocatalysis as a promising alternative for the degradation of organic compounds in water; and (2) to model the chemical reactions by the application of two different approaches based on adsorption – surface reactions (Langmuir–Hinshelwood) and its simplification to a first order rate reaction. These objectives were motivated by the lack of information regarding simultaneous degradation of organic compounds in different categories as found in real aqueous matrices, and generation of specific intermediates that could eventually represent a potential risk to the environment. Contaminants were chosen based on their occurrence in water sources, their representativeness of individual sub-categories, and their importance as part of the CCL3 as potential contaminants to be regulated. Contaminant degradation was evaluated over time, and the TiO2 concentration and solution pH were varied under constant UV irradiation, oxygen delivery rate, mixing gradient, and temperature.
Specific accomplishments of this study were: (1) reaction kinetics data were obtained from the UV/TiO2 experiments and showed the potential that this UV/TiO2 process has for effectively removing different types of organic compounds from water; (2) a good fit was obtained between photocatalytic reaction kinetics models and the contaminant data using pseudo first-order and Langmuir-Hinshelwood (L-H) models; (3) results of the analytical methods developed in this study were validated by measurements performed by a certified laboratory; (4) the reaction kinetic parameters obtained in this study were normalized to electrical energy per order, reactor volume and surface area of the photocatalyst in order to provide rate constants with wider applicability for scale-up to more complex systems; and (5) degradation intermediates from the oxidation process and from interaction among compounds were identified and possible pathways for their formation suggested. This research has provided a better understanding of the photocatalytic process for the removal of organic contaminants from complex aqueous matrices."
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Lingegowdaru, Jagadeesh. "Effect of UV-C hormesis on quality attributes of tomatoes during post treatment handling." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18285.
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Effect of UV-C Hormesis on Quality Attributes of Tomatoes during Post treatment Handling Post harvest losses are quite high in fresh fruits and vegetables. Although refrigeration is an effective method of storage, its advantage is limited to some crops that are not susceptible to chilling injury. Tomato (Lycopersicon esculentum Mill.) is one such crop where other alternatives are sought for. Experiments were conducted to assess the effect of post-harvest treatment with artificial ultraviolet (UV-C) radiation (~254 nm) on quality and physiology of treated tomatoes during post treatment handling. Antioxidant composition of tomatoes was studied in relation to the consequence of UV irradiation. Tomato fruits (variety DRK-453) were irradiated (3.7 kJ/m2) at mature green stage and stored at 13oC and 95% RH along with a set of control. The tomatoes were randomly sampled after 10, 20 and 30 days from the cold storage chamber, and ripened for 7 and 14 days at room temperature and analyzed for different quality parameters. The results showed that post-harvest UV treatment significantly reduced the surface color change of tomatoes whereas the other quality parameters such as TSS, titratable acidity, pH and TSS/acidity ratio were not influenced. This indicates that ripening process had similar pace in both control and UV treated fruits. Apparent firmness observed in the irradiated fruits was not reflected in the objectively measured firmness values. Today, estimation of antioxidant activity has become an important parameter to evaluate the nutritional quality of food. In tomato fruit the carotenoid lycopene is the main phytochemical purported to carry benefit to human health. UV treatment induced a significant decrease in the lycopene content of tomatoes in the later stage during handling. The other antioxidant components namely, ascorbic acid and total phenolic contents increased with the increase in storage and ripening period. The significantlyEffets d’un traitement hormesis aux UV-C sur la qualité post-récolte des tomates Les pertes après-récolte des fruits et des légumes sont relativement élevées. Quoique que l’utilisation du froid a permis d’accroître de façon marquée la durée de conservation de plusieurs fruits et légumes, ses effets bénéfiques sont limités sur les produits sensibles au froid comme la tomate (Lycopersicon esculentum Mill.). Des essais en laboratoire ont été effectués pour évaluer les effets d’un traitement hormesis au rayonnement ultraviolet (UV-C) sur la qualité de la tomate. Ce traitement aurait pour effet de causer un stress physiologique bénéfique qui se traduirait par une amélioration de la conservation et des qualités nutritives du fruit. Des tomates de variété DRK-453 et ayant atteintes un stage de maturité verte/mature ont été divisées en deux lots. Le premier a été exposé à un traitement hormesis au UV-C (3.7 kJ/m2) tandis que le second a servi de contrôle. Immédiatement après le traitement, tous les fruits ont été entreposés à 13oC et 95% d’humidité relative. Après 10, 20 et 30 jours de conservation au froid, des échantillons de tomates ont été prélevés de façon aléatoire dans chacun des lots. Puis, les fruits ont mûri à la température de la pièce pour une période de 7 ou 14 jours. A la fin du mûrissement, la qualité de conservation et la qualité nutritive ont été évaluées. L’analyse comparative des résultats a indiqué que, chez la tomate, l’exposition à la dose prescrite du rayonnement UV-C réduisait de façon significative le développement de la couleur rouge, mais qu’il n’affectait pas le pH, la fermeté, l’acidité titrable, la teneur total en solides solubles (TSS) et le rapport TSS/acidité. Par conséquence, le processus de mûrissement était similaire pour les fruits traités et non-traités. La tomate contient une quantité appréciable d’antioxydants do
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Zeng, Minzhen. "Investigations of operating conditions to improve the UV transmittance in chemically enhanced primary treatment /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?EVNG%202009%20ZENG.
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Wood, Rebekah. "Lipid Raft TNF-a Pathway Analysis of Cytochrome C with Methylparaben and UV-B Treatment." Marietta College Honors Theses / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=marhonors1430066140.
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Gupta, Abhinav. "Characterization and treatment of UV quenching substances and organic nitrogen in landfill leachates and thermal hydrolysis/anaerobic digestion centrate." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/22049.
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Landfill leachates and thermal hydrolysis pretreated anaerobic digestion centrate can quench UV light at publically owned treatment works (POTWs). Increased eutrophication, has led to tightening of nutrient discharge limits in some regions of the country. Biologically recalcitrant organic nitrogen, adds to effluent nitrogen making it difficult to meet these requirements.The study aimed at characterizing landfill leachate and centrate fractions to develop an understanding that might help design on-site treatment methods. Leachates varying in on-site treatment and ages were fractionated on basis of hydrophobic nature. Humic substances were the major UV light quenching fractions. Majority of the humic substances were > 1 kDa molecular weight cut off (MWCO) indicating that membrane treatment might be effective for UV quenching substances removal. UV absorbing substances were found to be more bio-refractory than organic carbon. Significant decrease in humic substances with long term landfilling indicated that age was important in determining the potential for leachates to impact the UV disinfection. Organic nitrogen was observed to be hydrophilic in nature (mostly < 1 kDa). Proteins which are easily biodegradable contributed around one-third of the organic nitrogen.
For thermal hydrolysis centrate, the optimum treatment depended on particle size and hydrophobic nature. Biological treatment was observed to be more effective for the removal of
organic matter and UV254 quenching substances for fractions < 300 kDa. Biological treatment had little impact on organic nitrogen. Coagulation-flocculation is an effective treatment for higher molecular weight (MW) fractions whereas a membrane bioreactor would be more suitable for smaller MW fractions.
Master of Science
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Kanagalingam, Sabeshan. "Synthesis and characterization of UV-crosslinkable peptide-based polymers for the use in glaucoma treatment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0004/MQ40732.pdf.
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Driskill, Natalie Marie. "Characterization and treatment of organic matter, UV quenching substances, and organic nitrogen in landfill leachates." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/51044.
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Landfill leachates are often treated on-site before disposal to municipal wastewater treatment plants, although variations in leachate composition and organic loading continue to have negative impacts on downstream treatment processes. Leachate samples were collected from four landfills both before and after on-site treatment to evaluate the extent of biological treatment. The samples vary in age, location, and on-site treatment processes. Size fractionation utilizing microfiltration (MF) and ultrafiltration (UF) was conducted in conjunction with TOC, nitrogen species, and UV254 absorbance analysis to determine the characteristics of organic constituents present in landfill leachate. The size fraction less than 1thousand Daltons (1 kDa) was responsible for a predominant portion of the organic fraction of the landfill leachates studied. Humic substances are refractory components present in landfill leachates that are resistant to biological treatment and responsible for a portion of the UV quenching ability of leachates. Humic substances were also fractionated to humic acid (HA), fulvic acid (FA), and hydrophilic (Hpi) components before being subjected to size fractionation to determine UV254 absorbance and organic fractions. Particle size and hydrophobic-hydrophilic fractionation were conducted in series to evaluate the potential for membrane treatment after biological treatment as a cost effective alternative to reverse osmosis processes currently used to decrease the organic fractions present in landfill leachate. The organic nitrogen fraction was predominately in the hydrophilic fraction smaller than 1 kDa.Master of Science
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Riley, Scott. "Measuring Viability of the Red-Tide Dinoflagellate Lingulodinium polyedra Following Treatment with Ultraviolet (UV) Light." NSUWorks, 2014. http://nsuworks.nova.edu/occ_stuetd/4.
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Harmful algae blooms (HABs) have caused millions dollars in annual losses to the aquaculture industry, inhibited beach recreation, and have threatened marine and human health. HABs and red tides can develop suddenly and their frequency, geographic range, and intensity have increased over the past decade. A possible source for spreading and seeding new areas expanding the geographic range of HABs is ballast water. The process of ballast water discharge has been identified as a primary vector for the translocation of non-indigenous species (NIS) and invasive species. National and international efforts are currently underway to address the impact of NIS and invasive species. Policy is being developed detailing stringent rules to kill, remove, or otherwise inactive organisms in ballast water prior to or upon discharge. Currently, vendors are developing technologies to treat ballast water and U.S. and international facilities are testing these technologies to verify their efficacy. Ultraviolet (UV) radiation is commonly employed in ballast water treatment technologies. Previous studies have shown that UV light is effective for disinfecting drinking water, but the response of non-pathogenic and marine organisms is largely unknown.
The purpose of this research was to measure the viability of the durable red-tide forming dinoflagellate, Lingulodinium polyedra following UV treatment. Two methods were used to measure the viability signal; manual epifluorescence microscopy with correlated viability stains and Pulse Amplitude Modulated (PAM) fluorometry to measure the physiological state of the organism following UV treatment. The number of cysts was also enumerated. The results showed that there was a significant decrease in the number of living L. polyedra cells following a UV treatment of more than 100 mWs cm-2. The results also have showed a significant increase in the number of L. polyedra cysts following UV treatment as low as 50 mWs cm-2.
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Brezavšček, Miha [Verfasser], and Wael [Akademischer Betreuer] Att. "Effect of UV light treatment on the osteoconductivity of a zirconia-based material = Effekt von UV Licht Bestrahlung auf die Osteokonduktivität von Zirkon-basierten Materialien." Freiburg : Universität, 2012. http://d-nb.info/1123473897/34.
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Metz, Deborah H. "The Effect of Natural Organic Matter on UV/H2O2 Treatment and the Effect of UV/H2O2 Treatment on Natural Organic Matter." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1337007191.
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Bergman, Gerald R. "Evaluation of Exposure to Optical Radiation in Medical Diagnostics and Treatment." University of Toledo Health Science Campus / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=mco1095952844.
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Rodríguez, Miguel. "Fenton and UV-vis based advanced oxidation processes in wastewater treatment: Degradation, mineralization and biodegradability enhancement." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/1522.
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Up until relatively recently, the discharging of waste in the environment was the way of eliminating them, until the auto-purifying capacity of the environment was not sufficient. The permitted levels have been vastly exceeded, causing such environmental contamination that our natural resources cannot be used for certain uses and their characteristics have been altered. The main problem stems from waste coming from industry and agriculture, despite the fact that the population also plays an important role in environmental contamination. Phenols, pesticides, fertilizers, detergents, and other chemical products are disposed of directly into the environment, without being treated, via controlled or uncontrolled discharging and without a treatment strategy.
In this general context, it is very clear that the strategy to continue in the search of solutions to this problem that every day presents a sensitive growth, mainly in the developing countries, will be guided to two fundamental aspects:
- The development of appropriate methods for contaminated drinking, ground, and surfaces waters, and mainly
- The development of appropriate methods for wastewaters containing toxic or non-biodegradable compounds.
This thesis is focused in the second of these aspects. In this sense, it has been deepened in the treatment of organic compounds in aqueous solution by means of advanced oxidation processes (AOP), in the search of their elimination or transformation into more biodegradable compounds.
The experimental work has been divided into four chapters. First part (chapter 3) is focused on the kinetic study of Fenton process for what two model compounds have been chosen: phenol, as reference (model compound widely studied) and an aromatic non-biodegradable compound, nitrobenzene.
The second part (chapter 4) addresses to the optimisation of some treatment processes, such as photo-Fenton, H2O2/UV and Fe3+/UV-vis using different sources of artificial light and sunlight. The experimental work of this chapter was divided into two parts. In the first one, experiments were performed at laboratory scale at the University of Barcelona. In the second one, experiments in pilot plants were carried out at the EPFL (Ecole Politechnique Federale de Lausanne, Switzerland) and at the Plataforma Solar de Almería, Spain. The experimental results showed that the photo-Fenton process was the most effective method in the mineralization of the treated solutions. It is very important to stand out that it was more effective when solar light was used as radiation source.
Chapters 5 and 6 represent an application of the treatment methods used in chapter 4, in which their influence on the biodegradability of an organic chloride compound (DCDE) and of waters coming from a textile industry was studied. For this final part of the thesis, the experimental work was carried out at the University of San Diego (San Diego, USA) and at the EPFL (Lausanne, Switzerland), respectively. In the case of water solutions of DCDE, H2O2/UV process was used as pre-treatment method to obtain oxidized solutions of 25, 50, 75 and 100% DCDE degrdation. After applying different biodegradability tests, it was observed that, as the percentage of oxidation increased, it increased the biodegradability of the treated solution, thus demostrating the effectiveness of the pre-treatment. In the case of treated textile wastewaters, a strategy was put in practice to obtain a general vision when it facing the case industrial wastewaters. When applied to the textile water under study, it was found that the photo-Fenton process should be used as post-treatment step of a biological process.
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Komvuschara, Kanyarat. "UV disinfection in comparison with other small scale disinfection technologies for the treatment of domestic greywater." Thesis, University of Hertfordshire, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247322.
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Qiu, Yong. "STUDY ON TREATMENT TECHNOLOGIES FOR PERFLUOROCHEMICALS IN WASTEWATER." Doctoral thesis, 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/44143.
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学位授与年月日: 2007-07-23 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2837号Perfluorochemicals (PFCs) were produced by industries and consumed “safely” as surfactants, repellents, additives, fire-fighting foams, polymer emulsifiers and insecticides for almost fifty years. However they are now considered as persistent, bioaccumulated and toxic (PBT) chemicals, and ubiquitously distributed in waster, air, human body and biota. Although some efforts were contributed to reduce PFCs in environment, such as development of alternatives and recycling processes, huge amount of persisted PFCs have already been discharged in environment and accumulated in biota including humans. In some industrialized areas, such as Yodo river basin in Japan, water environment and human blood were polluted by some PFCs, and thus reduction and control of PFCs were urgently required for the purpose of environmental safety and human health in these areas. Unfortunately, some studies implied that current water and wastewater treatment processes seemed ineffective to remove PFCs in trace levels. Therefore, this study will try to develop some proper technologies to treat trace level of PFCs in wastewater. In order to achieve this main objective, several works have been accomplished as follows. Current available literature has been reviewed to obtain a solid background for this study. Basic information of PFCs was summarized in physiochemical properties, PBT properties, productions and applications, regulations and etc.. Analytical methods for PFCs, especially of LC-ESI-MS/MS, were reviewed including pretreatment processes in diverse matrices, which derived objectives of chapter III. Distributions and behavior of PFCs were briefly discussed in water environments, biota sphere and human bloods. Available control strategies were shown in detail about alternatives, industrial recycling processes, and newly developed treatment processes. Current wastewater treatment processes showed inefficient removal for some PFCs, deriving objectives of chapter IV on the PFC behavior in treatment process. Newly developed treatment technologies seemed able to decompose PFCs completely but unsuitable for application in WWTP. Therefore, granular activated carbon (GAC) adsorption and ultra violet (UV) photolysis were developed in chapter V and VI as removal and degradation processes respectively. Fifteen kinds of PFCs were included in this study, consisting of twelve kinds of perfluorocarboxylic acids (PFCAs) with 4~18 carbons and three kinds of perfluoroalkyl sulfonates (PFASs) with 4~8 carbons. An integral procedure was developed in chapter III to pretreat wastewater samples. LC-ESI-MS/MS was applied to quantify all PFCs in trace level. Pretreatment methods were optimized between C18 and WAX-SPE processes for aqueous samples, and between IPE, AD-WAX and ASE-WAX processes for particulate samples. Standard spiking experiments were regularly conducted for each wastewater sample to calculate recovery rate and control analytical quality. As the result, WAX-SPE showed better performance on samples with very high organics concentrations, and C18-SPE performed better for long-chained PFCs. ASE-WAX was proposed as the optimum method to pretreat particulate samples because of the simple and time saving operations. 9H-PFNA was used as internal standard to estimate matrix effect in wastewater. Behavior of PFCs in a municipal WWTP has been studied in chapter IV by periodical surveys for six times in half a year. All PFCs used in this study were detected in WWTP influent and effluent. According to their carbon chain lengths, all PFCs can be classified into “Medium”, “Long” and “Short” patterns to simplify behavior analysis. PFCs in same pattern showed similar properties and behavior in wastewater treatment facilities. Very high concentrations of PFCs existed in WWTP influent, indicating some point sources of industrial discharge in this area. “Medium” PFCs, such as PFOA(8), PFNA(9) and PFOS(8), were primary contaminants in the WWTP and poorly removed by overall process. Performances of individual facilities were estimated for removal of each PFC. Primary clarification and secondary clarification were helpful to remove all PFCs in both aqueous phase and particulate phase. “Medium” PFCs in aqueous phase were increased after activated sludge process, but other PFCs can be effectively removed. Ozone seemed ineffective to decompose PFCs because of the strong stability of PFC molecules. Sand filtration and biological activated carbon (BAC) filtration in this WWTP can not remove PFCs effectively too, which required further studies. Performances of combined processes were estimated by integrating individual facilities along the wastewater flow. Activated sludge process coupled with clarifiers showed satisfied removal of most PFCs in the investigated WWTP except “Medium” PFCs. Adsorption characteristics of PFCs onto GAC have been studied by batch experiments in chapter V. Freundlich equation and homogenous surface diffusion model (HSDM) were applied to interpret experimental data. Isothermal and kinetics experiments implied that PFC adsorption on GAC was directly related with their carbon chain lengths. By ascendant carbon chain length, adsorption capacity for specific PFC was increased, and diffusion coefficient (Ds) was decreased. Ds of GAC adsorption was also decreased gradually in smaller GAC diameters. Coexisted natural organic matters (NOMs) reduced adsorption capacities by mechanism of competition and carbon fouling. Carbon fouling was found reducing adsorption capacity much more intensively than competition by organics. Acidic bulk solution was slightly helpful for adsorption of PFCs. However adsorption velocity or kinetics was not affected by NOM and pH significantly. GAC from Wako Company showed the best performance among four kinds of GACs, and Filtra 400 from Calgon Company was considered more suitable to removal all PFCs among the commercial GACs. Preliminary RSSCT and SBA results implied that background organics broke through fixed GAC bed much earlier than trace level of PFCs. Medium-chained PFCs can be effectively removed by fixed bed filtration without concerning biological processes. Direct photolysis process has been developed in chapter VI to decompose PFCAs in river water. Irradiation at UV254 nm and UV254+185 nm can both degrade PFCAs. Stepwise decomposition mechanism of PFCAs was confirmed by mass spectra analysis, and consecutive kinetics was proposed to simulate experimental data. PFASs can also be degraded by UV254+185 photolysis, although the products have not been identified yet. Coexisted NOMs reduced performance of UV photolysis for PFCAs by competition for UV photons. Sample volume or irradiation intensity showed significant influence on degradation of PFCAs. Local river water polluted by PFOA can be cleaned up by UV254+185 photolysis effectively. Ozone-related processes were also studied but ineffective to degrade PFC molecules. However, PFCs could be removed in aeration flow by another mechanism.
京都大学
0048
新制・課程博士
博士(工学)
甲第13340号
工博第2837号
新制||工||1417(附属図書館)
UT51-2007-M963
京都大学大学院工学研究科都市環境工学専攻
(主査)教授 田中 宏明, 教授 藤井 滋穂, 教授 伊藤 禎彦
学位規則第4条第1項該当
Doctor of Engineering
Kyoto University
DFAM
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Cheng, Peiyao. "Chemical and photolytic degradation of polyacrylamides used in potable water treatment." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000566.
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Martins, Armando Carvalho de Oliveira. "Processo oxidativo avançado UV/H2O2 na oxidação da carbamazepina : avaliação por ensaios respirometricos e ecotoxicologicos." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257867.
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Orientador: Alexandre Nunes PoneziDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-13T11:19:54Z (GMT). No. of bitstreams: 1 Martins_ArmandoCarvalhodeOliveira_M.pdf: 1218959 bytes, checksum: 89c4972bf88120caa1add6b7b1eb515a (MD5) Previous issue date: 2009
Resumo: O efeito da poluição é resultado inerente da ocupação humana com grande impacto ao ambiente. Um problema atual é a contaminação dos corpos d'água com produtos de origem industrial, agrícola e produtos de origem farmacológica e de cuidado pessoal. Os fármacos são considerados contaminantes ambientais devido a estas moléculas serem biologicamente ativas. Neste trabalho foi estudada a biodegradabilidade direta da carbamazepina, sua degradação por processo oxidativo avançado e por processo oxidativo avançado seguido de respirometria. Foi utilizado como metodologia a cromatografia em camada delgada, cromatografia líquida de alta eficiência, análises toxicológicas, respirométricas, demanda química de oxigênio e carbono orgânico total. A avaliação do potencial de biodegradação direta da carbamazepina por microrganismos provenientes do lodo ativado e do solo não apresentaram resultados satisfatórios. A melhor concentração de carbamazepina a ser utilizada no processo oxidativo, foi de 10 ppm. As análises de carbono orgânico total, referente ao processo de oxidação em reator de ultravioleta com peróxido de hidrogênio, realizadas após o tratamento mostraram que a taxa de remoção de carbono da solução foi de 1%. A análise da demanda química de oxigênio, realizada a partir das amostras geradas do reator nos tempos de reação de 5, 15, 30, 45 e 60 minutos não apresentou qualquer mudança significativa. Os ensaios de respirometria (biodegradação) mostraram uma degradação de aproximadamente 1% do composto químico para todos os tratamentos com ultravioleta com peróxido de hidrogênio utilizados. Nos testes de biodegradabilidade os microrganismos não foram capazes de utilizar o fármaco como fonte de carbono e energia mesmo após o tratamento com ultravioleta com peróxido de hidrogênio. A avaliação do desenvolvimento dos microrganismos durante o ensaio de biodegradação apresenta decréscimo acentuado do número de microrganismos viáveis presentes tanto para o composto puro como também para os ensaios realizados após o tratamento com ultravioleta com peróxido de hidrogênio. Os subprodutos gerados no processo oxidativo avançado apresentam efeitos tóxicos agudos para a Ceriodaphinia dúbia e Vibrio fischeri nos ensaios toxicológicos.
Abstract: Pollution is a direct result of human occupation. Since the big human conglomerates appeared became clear its harmfulness to the environment. Today there is a growing concern with water pollution by industrial, agricultural, pharmaceutical and personal care products. Pharmaceutical and personal care products contaminates the water in the domestic effluent, or in an inappropriate disposal of then in urban trash. The pharmaceutical products are considered environmental contaminants because their molecules are biologically actives. In this study the direct biodegradability of carbamazepine, its degradation by advanced oxidation process and advanced oxidation process followed by respirometry were evaluated. The total organic carbon, chemical oxygen demand, thin layer chromatography, high pressure liquid chromatography and respirometry were utilized to obtain the results of this work. The biodegradability results by microorganisms in soil and silt were not satisfying. An optimal concentration of 10ppm of carbamazepina was used in the advanced oxidation process. The total organic carbon results of the advanced oxidation process in UV/H2O2 reactor after the treatment revealed a removal rate of 1%. The respirometry assays showed less than 1% degradation of the chemical compound for all UV/H2O2 treatment. The results indicate that the microorganisms were not able to use the pharmaceutical product as a carbon and energy source even after UV/H2O2 treatment. The evaluation of microscopic development during the biodegradation assays revealed a drastic fall in the number of viable microorganisms presents in the pure compound as well as after the advanced oxidation process. The toxicological assays showed that the advanced oxidation process generated sub products and have acute toxicological effects for Ceriodaphinia dúbia and Vibrio fischeri.
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil
32
Fustini, Lorenzo. "Mechatronic solutions in agritech: design of post-harvesting robotic system for strawberries and prototyping of mobile soil-testing platform." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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Il settore agro-alimentare sta diventando un notevole business per le industrie a causa del crescente interesse per il concetto di sicurezza alimentare e della necessità di nutrire il mondo globale. In particolare, il Regno Unito ha investito considerevoli risorse nella ricerca e nello sviluppo per ottimizzare la produttività: questo lavoro di tesi si inserisce in quest’ambito. In particolare le soluzioni meccatroniche analizzate, vertono su due diversi casi di studio:
• la progettazione di un’innovativa linea di confezionamento per le fragole;
• sviluppo di una piattaforma mobile per il test del suolo.
Il primo progetto, in collaborazione con Berry Gardens, azienda leader nel Regno Unito nel commercio della frutta rossa, consiste nel ri-progettare una linea di confezionamento fragole. Partendo da un attuatore di Bernoulli, lo studio preliminare si è concentrato sulla progettazione di una nuova generazione di manipolatori in grado di minimizzare i danni sul prodotto, con annessi relativi test per valutare le sue potenzialità. Inoltre, è stata sviluppata una stazione di trattamento UV in grado di trattare fragole su entrambe le superfici per massimizzare l’effetto di decontaminazione. Infine è stata presentata la soluzione finale della linea di confezionamento.
Il secondo progetto, in collaborazione con l'università norvegese University of Life Sciences, ha come obiettivo quello di assemblare una piattaforma composta dal robot mobile Thorvald II sviluppato dall'Università norvegese, e un robot cartesiano, prodotto dalla società SMC, al fine di costituire una piattaforma mobile autonoma per l’analisi del suolo.
Entrambi i progetti sono stati sviluppati presso l'Università di Lincoln, Regno Unito, con la collaborazione di School of Engineering, School of Computer Science, Lincoln Institute for Agri-Food Technology (LIAT) e di partner industriali dell'Università.
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Cates, Stephanie. "Materials modification strategies to improve praseodymium-doped visible-to-ultraviolet upconversion systems for environmental applications." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54907.
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UV radiation is utilized in a number of environmental technologies, most notably for the disinfection of water, air, and surfaces through the use of UVC fluorescent lamps. Recently, our group developed a luminescent material that could emit germicidal UVC simply by irradiating it with a household fluorescent lamp, thus introducing a new type of antimicrobial surface powered by low-intensity visible light. The materials were doped with praseodymium ions (Pr3+) which have the unique capability of converting visible light to higher energy UV using an optical mechanism called upconversion. While visible-to-UV upconversion materials appeared promising for environmental application—particularly because solar irradiation could be used for their activation—their practical application was thwarted by low light conversion efficiencies. Herein we discuss the pursuit of new material forms and modifications designed to improve the efficiency of Pr3+-based upconversion systems. These enabled successful enhancement of antimicrobial activity and led to a proof of concept for upconversion-sensitized TiO2 photocatalysis. Correlations between material properties and optical behavior will be presented, followed by commentary on how these strategies might be used to further advance upconversion systems toward environmental application.
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Peppiatt, Christopher J. "The characterisation of a thin film UV contactor and its application to the treatment of contaminated cutting oils." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/13716.
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The characteristics and applications of a novel design of a thin film photocontactor based on the principle of irradiating a 'water bell' with ultraviolet (UV) light a,e considered in this work. Measurements of UV doses received by the liquid films in single passes were made using both actinometric and bioassay-based methods. The chemical actinometer employed was potassium ferrioxalate (K,Fe(C,o.l,)) and the microorganisms used in the bioassay were Pseudomonas stutzeri (mRG) and a repair-deficient strain of Escherichia coli (NCIMB 11190). Good agreement was obtained between the doses measured using actinometry and the E. coli-based bioassay. At higher doses, good agreement was also obtained for the dose estimates made using actinometry and the Ps. stutzeri bioassay. In addition, a hydrodynamic water bell model, previously developed in the literature, was combined with a UV intensity model to predict UV doses with generally good results. Microbially contaminated metal working fluids were identified as a suitable medium for disinfection using the thin film contactor because they are not treatable using conventional UV contactors, and because the systems employed in industry vary widely in scale. Batches of contaminated emulsion ranging in volume from 200 to 1000 L were successfully disinfected. Representative members of the microbial population were isolated, and their changing status throughout treatment recorded. Against expectations, the population showed no capacity for the post-irradiation repair of UV-induced damage. A simplified disinfection model was established in order to model the treatment of batches of contaminated metal working fluids. Preliminary predictions made using a combination of experimental data for the population as a whole and that for individual species coupled with that generated using the hydrodynamic bell model, gave encouraging results.
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Helali, Sihem. "Application de la photocatalyse pour la dégradation des polluants chimiques et bactériologiques dans l’eau en utilisant des catalyseurs irradiés par des photons de lumière naturelle ou artificielle (UV‐A /UV‐B)." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10316/document.
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La dégradation photocatalytique de deux amines, la méthylamine (MA) et la diméthylamine (DMA), a été étudiée en présence de TiO2 Degussa P25. Différents paramètres ont été étudiés: l'adsorption à l’obscurité et sous UV, la photolyse, les cinétiques de dégradation, l'effet du pH, l'effet de la nature et de l'intensité du flux photonique ainsi que les voies de dégradation de la MA et DMA.A l’obscurité, le taux de recouvrement des groupes OH est similaire pour la MA et DMA. Sous UV, ce taux devient deux fois plus élevé pour la MA. Les réactivités de MA et DMA sont directement corrélées à leur adsorption sous UV. Les atomes d'azote sont principalement décomposés en ammonium. Le nitrite a été également détecté, mais rapidement oxydé en nitrate. À pH basique, l'hydrolyse photo‐assisté et l'attaque de OH• sur l’atome N augmente. DMA est essentiellement transformé en MA. Les analyses du Carbone Organique Total (COT) montrent la présence de produits finaux contenant de l’azote difficilement minéralisables. Nous avons montré que, quelle que soit l'énergie des photons (UV‐A ou UV‐B), le rendement quantique reste constant et égal à 0,033.L'inactivation photocatalytique de E. coli en présence de la lumière solaire naturelle en absence (SODIS) et en présence de différents catalyseurs a été étudiée. L'effet de la température sur l'inactivation de E. coli a été aussi étudié. Les résultats ont montré que l’addition des différents types de catalyseurs accélère l'effet bactéricide du rayonnement solaire. Aucun phénomène de reviviscence bactérien n’a été observé après l'arrêt de l'exposition solaire durant au moins 72 heures. Seulement les ions ammonium et potassium ont été détectés au cours de l'inactivation de E. coli en accord avec la perforation de la membrane et l’oxydation des protéinesThe photocatalytic degradation of two amino‐compounds, methylamine (MA) and dimethylamine (DMA) was investigated in the presence of UV‐irradiated TiO2 aqueous suspensions. Different parameters were studied: adsorption under dark and UV conditions, photolysis, kinetics of degradation, effect of pH, effect of the nature and intensities of photonic flux and finally the chemical pathway MA and DMA degradation.While, the percentage of covered OH in the dark was equal for MA and DMA, it becomes twice higher for MA under UV. The reactivity of MA and DMA is directly correlated with the adsorption under UV. The nitrogen atoms were decomposed mainly to ammonium. Nitrite was also formed but was rapidly oxidized to nitrate. At basic pH, photo assisted hydrolysis and the attack of OH• on N‐atom increase. DMA is mainly transformed to MA. Total Organic Carbon (TOC) analysis show the presence of final slightly mineralised intermediate compounds containing nitrogen atom. We shown that, whatever the energy of photons (UV‐A or UV‐B), the same quantum yield equal to 0.033 was obtained.The photocatalytic inactivation of E. coli under natural solar irradiation in the absence (SODIS) as well in the presence of different concentrations of varied photocatalysts has also been investigated. The effect of temperature on E. coli inactivation was studied. Results show that the additions of any types of catalyst to the water accelerate the bactericidal action of solar irradiation and leads to a total disinfection. No bacterial regrowth was observed during the subsequent dark period. Ammonium and potassium ions were formed during E. coli inactivation in agreement with the membrane perforation and the oxidation of proteins
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Nguyen, Ha Thi. "Effect of transmittance and suspended soils on the efficacy of UV disinfection of bacterial contaminants in water." Title page, contents and summary only, 1999. http://web4.library.adelaide.edu.au/theses/09AS/09ash111.pdf.
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Errata pasted onto front end-paper. Bibliography: leaves 113-120. To obtain robust and quantitative data on the influence of UV absorption and suspended solids on UV disinfection an experimental study using commercial disinfection technology was undertaken.
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Hung, Hung-Ping, and 洪鴻斌. "Treatment of Refractory Dyestuffs Wastewater Using H2O2/UV和H2O2/UV/Fe2+ Processes." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/84472903022627385695.
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碩士淡江大學
水資源及環境工程學系
85
This study was conducted to treat dye manufacturing wastewater using H2O1/UV and H2O2/UV/Fe2+ processes, which serve to pretreat the loading in the subsequent treatment processes or polish the secondary effluent to comply with discharge regulation. Dye manufacturing wastewater, if not appropriately treated, might impose on the receiving waters a severe threat because of its high levels of refractory organic compounds, color, and chloride ion salt. Base on the literature report, it is understood that dyestuff can not be completely removed by biological treatment, due to its inhibiting effect microorganism. Both processes mentioned above are capable of generating strong oxidant, called hydroxyl radical, which can oxidize effectively the target organics to achieve the treatment goal. The emphasis of this study was placed on the effect of ferrous ions and peroxide dosages, UV intensity, chloride ions concentration, pH, and dilution ratio of original wastewater sample on the residual fractions of COD, H2O2, ABS254 and ADMI color value. As a result the enhanced effect by adding excess H2O2 is very limited due to its OH‧ scavenging. In general, the removals of ABS254, ADMI color value were found faster than that of COD. The pH condition for the best removal of ABS254, ADMI color value, and COD occurs at around pH=3 or pH=4. Chloride ions show some inhibiting in removing COD, ABS254 and ADMI color value, however, its inhibiting effect on peroxide decomposition dose not necessarily increase with its concentration. Although, both processes show the some removal efficiency at the end of 2 hour reaction period, the removal rate is much slower using H2O2/UV process than H2O2/UV/Fe2+ process. It is suggested that add appropriate ferrous dosage in the early reaction period and then followed by supplementing sufficient amount H2O2 in the late reaction, in order to achieve the best process performance.
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Fang, Jian-Zhi, and 方建智. "Treatment of synthetic municipal wastewater by H2O2/UV process." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/09613905537558064034.
Full textAbstract:
碩士高苑科技大學
化工與生化工程研究所
98
This study evaluates the H2O2/UV process for the removal of dissolved organic carbon (DOC) from synthetic municipal wastewater. Experiment variables studied include pH, oxidation time, hydrogen peroxide dosage and UV intensity. The DOC reaction kinetic and specific energy consumption were also discussed. Moreover, the efficiency of H2O2/UV combined with membrane separation to removal DOC were evaluated. Results show that the residual DOC increased with an increase of initial pH. Howevwe, there was only little difference residual DOC between pH 3-8. The residual DOC are 30% at pH 3 and 35% at pH 8. In the neutral pH, UV=128W, H2O2 dosage are 250, 300, 350, 400 and 500 mg/L, oxidation time is 180 min, the residual DOC are 67%, 58%, 45%, 37% and 29%, respectively. The DOC removal followed pseudo first-order kinetics and the reaction rate constants increased with increasing H2O2 dosage. The reaction rate constands are 0.25 × 10-2, 0.33 × 10-2, 0.45 × 10-2, 0.57 × 10-2, and 0.74 × 10-2 min-1, respectively. The specific energy consumption are 10880, 8320, 32533, 2400, and 1822 KWhKg-1 DOC, respectively. It indicates that specific energy consumption obviously decreased with increasing H2O2 dosage. On the other hand, H2O2 dosage is 500 mg/L and UV intensity were controlled 16, 32, 64 and 128W at an oxidation time of 180 min. The residual DOC are 85%, 66%, 45% and 29%, respectively. The DOC removal followed pseudo first-order kinetics and reaction rate constants increased with increasing UV intensity. Pretreatment of the synthetic municipal wastewater by H2O2/UV oxidation can decrease silt density index (SDI) values from 6.1 to 0.1 and increase permeate flux from 15.3 L/m2h to 23.7 L/m2h when followed by RO separation. The total DOC removal of H2O2/UV combined with NF and RO separation are 92% and 98%. In addition, either H2O2 or UV light can be a disinfection to prohibit microorganism growth. The removal of nitrogen compounds by H2O2/UV alone was worse. In conclusion, the combined H2O2/UV pre-oxidation and membrane post-process is a promising treatment for synthetic municipal wastewater.
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Hu, Shuen-long, and 胡順隆. "ACETONE WASTEWATER TREATMENT BY UV/H2O2 ADVANCED OXIDATION PROCESS." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/15130519272214173704.
Full textAbstract:
碩士大同大學
化學工程學系(所)
97
The wastewater from semiconductor industries containing non-biodegradable and toxic organic compounds is one important issue environmental contamination. Many researches showed that advanced oxidation processes (AOPs) could treat organic contaminants by generating hydroxyl radical possessing mighty oxidation ability to decompose the contaminants non-selectively. In order to design an AOP, the reaction kinetic model for the specific pollutant is necessary information. This study aims at investigating the decomposition of acetone by UV/H2O2 process under varying experimental conditions such as agitation speed, hydrogen peroxide concentration, initial acetone concentration, reaction temperature, initial pH, UV irradiation power and dissolved oxygen concentration. The results show that the acetone decomposition rate increases with increasing agitation speed up to 500 rpm so that the mass transfer resistance can be neglected. The reaction rate remains almost constant at lower pH and then decreases with increasing pH values. The reaction rate has a optima ratio of hydrogen peroxide concentration. The reaction rate increases with increasing reaction temperature. The reaction rate decreases with increasing initial acetone concentration. The reaction rate increases with increasing UV irradiation power and dissolved oxygen concentration. A kinetic model for H2O2 decomposition by UV was proposed to correlate different H2O2 concentration at different temperatures. The experimental data and the model predicted results were in good agreement. An empirical kinetic model of acetone decomposition by UV was proposed to correlate different H2O2 and acetone concentration.
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Li, Bin-Hao, and 李彬豪. "Treatment of Domestic Primary Effluents by H2O2/UV Oxidation Processes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/16452775515412027306.
Full textAbstract:
碩士淡江大學
水資源及環境工程學系碩士班
98
This study evaluated the treatability of domestic primary effluents by H2O2/UV oxidation process. The primary effluents were sampled from a wastewater treatment plant located at Taipei County. The concentrations of chemical oxygen demand (COD), dissolved organic carbon (DOC), and suspended solids (SS) were 106-143, 14.6-19.7, and 34-46 mg/L, respectively. All experiments were conducted in a batch H2O2/UV photo-reactor. The experimental parameters included pH, oxidation time, H2O2 dosage and UV intensity. The oxidation and mineralization of organics in water samples was demonstrated by the change in DOC, UV254, and molecular weight (MW) fraction of DOC. The results showed that the removal of DOC at pHs 3-4 was better than that at pH 7 due to the higher production of hydroxyl free radicals (OH．). The optimum oxidation time ranged from 90 to 120 mins for the removals of DOC and UV254. The removal rates of DOC and UV254, and the degradation of H2O2 followed the pseudo-first-order kinetics. The removal of UV254 was faster than the removal of DOC. For most experimental conditions, the residual DOC showed a decreasing tend within first of the 90 mins oxidation time. In contrast, the residual DOC began to increase again as oxidation time was extended beyond 120 mins. This might be due to the colloidal organics being oxidized into detectable DOC. The removal of UV254 increased with increasing UV intensity and H2O2 dosage. Due to the competition for OH．between DOC and H2O2, the removal of DOC and UV254 did not increase with the increase of H2O2 dosage after an optimum H2O2 dosage had already been added. Furthermore, the DOC of a high molecular weight fraction was oxidized into DOC of medium and low MW fractions. After treatment, DOC of low MW(less than 1 KD) fractions predominated more than 95% of the residual DOC. It was concluded in this study that the optimal operational conditions for treating domestic primary effluents consisted of pH of 4, oxidation time of 90 min, H2O2 dosage of 400 mg/L and UV intensity of 96 watts. At the optimal operational condition, the removal DOC and UV254 reached 70 and 80%, respectively.
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Yi-Chang, Chen, and 陳奕璋. "Investigation on UV-assisted thermal treatment of SiCxNy Thin Films." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/75112129637199929706.
Full textAbstract:
碩士國立交通大學
材料科學與工程學系所
104
As the feature size of VLSI devices scaling down, a lower dielectric constant both in the interlayer dielectric (ILD) and etch-stop/diffusion barrier (ES/DB) layer is necessitated to slow down the increasing trend of RC propagation delay in the backend interconnect. However the critical problem is the dilemma between dielectric constant and mechanical properties of such dielectrics. When the dielectric constant is much reduced, its mechanical properties may be too weak to survive processes such as chemical-mechanical polish and packaging due to chip-package interaction. To solve this problem, UV-assisted thermal annealing has been used to post-treat carbon-doped silicon (SiCOH) ILD for reduced k-value but enhanced mechanical strength. Yet, there is a lack in the understanding if UV-assisted thermal anneal can favorably affect the dielectric constant and mechanical strength on the low-k ES/DB materials. This work investigates the effect of UV-assisted thermal annealing on the structure and properties of silicon carbonitride (SiCxNy) films for application in copper interconnects. In particular, SiCxNy films are deposited by plasma-enhanced chemical vapor deposition at substrate temperature 80 – 200 ℃ and 1 Torr using a single precursor, N-methyl-aza-2,2,4-trimethylsilacyclopentane (MTSCP). Comparative studies on post-treatment of SiCxNy films deposited at various temperatures are carried out using (1) thermal annealing at 400 ℃ for 5 minutes and (2) UV-assisted thermal annealing at 400 ℃ with 80 mW/cm2 UV light exposure for 5 minutes. In this study, UV-assisted thermal annealing is found to remove the organic phase, break up the high-polarizability NH bonding, and enhance SiN backbone structure. Thus, UV-assisted thermal anneal can enhance the properties of SiCxNy film compared to conventional thermal annealing under same curing time, 5 min. The optimal result of low-k SiCxNy film using MTSCP precursor was obtained by deposition at 150 ℃,1 Torr, and under a plasma power density of 0.27 W/cm2. Under these conditions, the dielectric constant of low-k SiCxNy film drops 0.22 from 4.05 to 3.83, while the Young’s modulus maintains the same at about 20 GPa. As a result, UV-assisted thermal annealing can be a powerful post-treatment technique to enhance silicon carbonitride films for backend interconnect applications.
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Hao-men, Shen, and 申浩民. "Treatment of Printed Wiring Board Electroplating Wastewaters by O3/UV." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/40618743220764801081.
Full textAbstract:
碩士國立臺灣大學
環境工程學研究所
91
This study was made to investigate the effect of ozonation on the wastewater resulting from a Printed Wiring Board (PWB) factory. Ozonation in the presence or absence of UV irradiation was carried out to remove the organic contents of either of the wastewater. When treated by plain ozonation, pH factors were also chosen to detect their influence over the overall oxidation processes. High metal ion concentrations focused in the wastewater were studied for their catalytic effects on ozonation. Results obtained indicate that (1) Ozonation on the acidic/basic wastewater resulting from a PWB factory and the organic contents in basic wastewater got the best removed effect. Whatever the acidic or basic wastewater got the best organic matters removed effect in the high basic oxidation processes. (2) Using ions exchanged resin to remove the high metal ion concentrations focused in the wastewater, then treated by previous oxidized conditions. Results obtained indicate that the removed effect of organics contents became low. To guess the metals having catalytic effects on ozonation (3) Using two of the important organic additives for the electroplating solution which are 2-Naphthalenesulfonic and 2-mercaptothiazoline. These solutions adding metals were treated by ozonation, then the removed effect of organics contents became high. (4) The effluent discharges which was treated by coagulation and settlement, treated by ozonation finding the removed effect of organics contents was poorer than the acidic/basic wastewater.
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Chia-Ting, Kuo, and 郭佳婷. "Treatment of aquaculture and dye wastewaters using TiO2/UV photoreactors." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/82239602207697005798.
Full textAbstract:
碩士國立屏東科技大學
環境工程與科學系所
96
TiO2 coated on a glass tube was used as a hetero-catalyst. The TiO2/UV photoreactor was used to treat aquaculture wastewater to replace the traditional method. It is expected to save the cost of using filters and active carbon. Time and cost may be minimized and to maintain the water quality. When the color of wastewater becomes darker, the dye wastewater required treatment. With the low concentration of treated dye wastewater, the environment is not seriously polluted. Self-produced TiO2-glass tubes were assembled , and UV photocatalytic system with different procedures were tested to treat dye and aquaculture wastewaters. Toxicity, mineralization, and decoloration were discussed under different conditions with various wastewater samples. At different experimental settings, the TiO2-glass tube results showed that wastewater samples can be completly treated in 300 min using W-2-glass tube. In order to understand the effect of UV light on TiO2 glass tube, the experiment using a black tube was conducted to compare with UV light. The result showed that the effect of black tube was negligible. W-2-glass tube was effective to increase photocatalytical efficiency with 0.25 M H2O2. Decoloration can reach 100 % in 30 min. However, too much H2O2 had adverse effect on the reaction efficiency. When pH was adjusted to 3, the reaction efficiency significantly improved. It is because that acidic conditions would boost the electrostatic attraction between the positively charged TiO2 surface and the reactant dyes. To combine 0.25 M H2O2 and pH 3, the decoloration can achieve 100 % in 20 min. If the pH was adjusted to 9, results showed that decoloration achieved 100 % in 40 min. The modification of pH conditions increased H2O2 effectiveness to assist photocatalyst reaction. Results of BET showed that using W-method TiO2 at 400℃ calcination, the specific surface area was 134.88 m2/g. The specific surface area was decreased as the temperature increased. At high temperature, the OH functional group on TiO2 could form mutual condensation bonding and nucleation reactions. XRD showed that the major form of TiO2 crystallization were anatase which showed that W-method possess was a better photocatalytic method. For the treatment of fish tank water sample in photocatalytic reaction, the SS of a fish tank water samples were reduced from 3.1 to 1.6 mg/L, and the turbidity were reduced from 3.87 to 2.71 NTU. For the treatment of aquaculture wastewater in the same conditions, the SS were from 76 to 7 mg/L, and the turbidity were from 9.99 to 2.67 NTU. The result showed that the photocatalytical reaction was efficient to treat related wastewater. Results of BOD study, the fish tank water sample and the aquaculture wastewater showed that original DO were 6.1 mg/L and 6.8 mg/L, and the BOD5 were 3.9 mg/L and 56 mg/L, respectively. The aquaculture wastewater had higher concentration of organic matter than that of fiah tank water. The photocatalysis did not demonstrate the degrading effect on NH4+. No matter what kind of wastewaters, COD showed significant degradation in this treatment. DOC removal rate of 34.45 % was detected in aquaculture wastewater after 8-hr of irradiation. Toxicity increased due to the formation of by-products in the water sample after 8-hr of irradiation. Contrarily, toxicity was decreased for dye wastewater after 5-hr of irradiation. Reusability of TiO2 was tested. The results showed that the intensity of UV lamp remained constant, and the TiO2 glass tube was still effective even used more than 50 times.
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Lee, Ting-Wei, and 李庭瑋. "Treatment of Nitrogenous Substances in Aqueous Solution by UV/H2O2 Process." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34579537262955971010.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
104
Degradation of nitrogenous substances, including ammonia and urea, in aqueous solution by UV/H2O2 process was studied under various initial solution pH, light intensity, initial hydrogen peroxide concentration and initial reactant concentration to evaluate the removal efficiencies of ammonia and urea. In the UV/H2O2 system, the initial solution pH was a significant factor to affect the degradation of ammonia. It is attributed to ammonia and hydrogen peroxide could decompose in aqueous solution with the pKa values of 9.3 and 11.6, respectively. Results showed that the degradation of ammonia was found to be enhanced with the increase of initial solution pH under alkaline condition, whereas there was no ammonia degradation under acidic and neutral conditions. However, the removal efficiency would decrease when the pH value above 11. On the other hand, the light intensity and initial hydrogen peroxide would also influence the removal efficiency of ammonia. Results showed that the degradation of ammonia increased with increasing light intensity and hydrogen peroxide dosage. However, further addition of hydrogen peroxide would decrease the removal efficiency of ammonia because of the excessive of hydrogen peroxide could become scavengers of hydroxyl radicals. In this study, the optimum operating conditions for degradation of ammonia in the UV/H2O2 system was as follows: initial solution pH 10, light intensity 8.93 mW/cm2, and initial hydrogen peroxide concentration 480 mg/L. according to the conditions, the maximum removal efficiency of ammonia is 45.33% after 120 minutes. Finally, it was no significant effect to remove urea in aqueous solution by UV/H2O2 process. This result would be explained by the property of urea in the aqueous solution. In the aqueous solution, urea is a stable compound due to resonance structures, which is hardly attacked by electrophile of hydroxyl radical.
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Tsai, Wei-Chun, and 蔡偉駿. "The influence of UV Ozone treatment on space charge limited transistor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/65070910728504089811.
Full textAbstract:
碩士國立清華大學
電子工程研究所
102
The organic transistor has become more and more active in recent years due to its advantages such as lower cost, simplicity in process, flexibility and high uniformity in large area which can hardly be found in the silicon transistor. This thesis will restrict transistors (space-charge-limited transistor, SCLT) components for internal process improvement space charge, so SCLT with high switching characteristics, high output current, high stability, high repeatability and low-cost liquid processes. Although SCLT can obtain astonishing switch ability when working as top-injection device . But in order to drive organic light-emitting diodes (Organic Light Emitting Diode, OLED), must let SCLT element overall output current, increasing the switching characteristics. Elements of the past in order to increase the output current using self-assembled monolayer (Self-Assembled Monolayer, SAM) to handle the space-charge-limited transistor (SCLT) vertical nano porous channels, significantly increasing the output current; This thesis is based on the UV Ozone to process light nano porous base element and the base version (base electrode), the degree of improvement of the insulation element, and to enhance the success of the output current density to SCLT 10mA/cm2 ratio characteristic and high switching transistor105, this method also has the advantages of low cost, process simplicity and good degree of stability.
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Barashkov, Nikolay, Anatoly Semenov, and Tamara Sakhno. "Chlorine-free disinfection of water contaminated with e. Coli: comparing efficacy of UV-treatment with combination of electrolysis, ultrasonic and photochemical treatment." Thesis, 2020. http://dspace.puet.edu.ua/handle/123456789/8382.
Full textAbstract:
Сучасне матеріалознавство та товарознавство: теорія, практика, освіта: матеріали VІІ Міжнародної науково-практичної інтернет – конференції (12-13 березня 2020 року, м. Полтава) – Полтава: ПУЕТ, 2020. – C.9-13.
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Pantin, Sophie. "Impacts of UV-H2O2 Treatment for Taste and Odour Control on Secondary Disinfection." Thesis, 2009. http://hdl.handle.net/1807/18973.
Full textAbstract:
The Cornwall Water Purification Plant collaborated with the University of Toronto to monitor UV-H2O2 treatment performance. This study includes a review of engineering and operational aspects of UV-H2O2 implementation. A number of operational challenges were experienced with retrofitting UV-H2O2 into the existing treatment plant, and an overview of the challenges and solutions faced at Cornwall is given. The project also includes a thorough water quality analysis. Taste and odour (T&O) events have been monitored for three years and the efficiency of UV-H2O2 on T&O removal is reported. Furthermore, little is known about any potential side effects of the treatment on downstream processes, especially secondary disinfection. The impact of UV-H2O2 on natural organic matter alterations, chlorine stability and disinfection by-product formation is reported using results from full-scale water quality monitoring campaigns at Cornwall, combined with laboratory experiments.
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Keithley, Sarah Elizabeth. "The effect of treatment on the quality of harvested rainwater." Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-05-5825.
Full textAbstract:
Harvested rainwater is an alternative water resource that can be utilized to help meet the world's growing demand for fresh water. Although harvested rainwater is often considered to have adequate physical and chemical qualities, its microbial quality has been found lacking. This study sought to better understand the effect of common treatment processes on the quality of harvested rainwater for potable use by examining two treatment processes: (1) batch chlorination followed by filtration, and (2) filtration followed by ultraviolet (UV) irradiation. The batch chlorination studies used rainwater harvested from four pilot-scale roofs in Austin, Texas with different roofing materials: concrete tile, green, Galvalume[Trademark] metal, and asphalt-fiberglass shingle. Chlorine tends to react with natural organic matter and produce disinfection byproducts (e.g., trihalomethanes (THMs)) that are harmful to human health. Chlorinating rainwater harvested from the metal and concrete roofs achieved adequate disinfection (total coliforms less than 1 colony forming unit per 100 mL) without forming THMs that exceed the United States Environmental Protection Agency (USEPA) limit of 80 [mu]g/L for public water systems. Chlorinating rainwater harvested from the shingle roof achieved adequate disinfection but had the potential to form excessive THMs. Chlorinating rainwater harvested from the green roof, which had the highest concentration of dissolved organic carbon, did not achieve adequate disinfection and formed THMs that were four times higher than the USEPA limit. Filtering the chlorinated rainwater from every roofing material with a block activated carbon filter generally resulted in increased bacteria concentrations and decreased THM concentrations. To study the effect of UV irradiation, cistern-stored and treated rainwater were sampled from a full-scale residential system in Austin, Texas, where the owner uses rainwater as his primary potable water supply. UV irradiation at the full-scale system effectively disinfected rainwater when the turbidity and total coliform concentrations were low, but disinfection was compromised as these two parameters increased as the drought progressed in 2011 and the ambient temperature increased. This research suggests that under certain conditions, treatment by either chlorination or UV irradiation can improve the quality of harvested rainwater so that it conforms to drinking water standards for public water systems.text
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Lo, Shih-Bon, and 羅世邦. "Inducing resveratrol synthesis in the skin of ''Kyoho''grapeby UV-C treatment." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/29794524935946114512.
Full textAbstract:
碩士臺灣大學
園藝學研究所
92
The objects of this research were to study the formation of the resvera- trol（3,5,4''-trihydroxystilbene） in the skin of grape that were treated with ultraviolet-C（UV-C）.And the resveratrol were analyzed with high performance liquid chromatography（HPLC）. ‘Kyoho’ grape that were treated with different dose of UV-C synthesized more resveratrol than the control. There were no difference among UV-C treatmemt, and there were no dosage effect between UV-C doses and resveratrol synthesis. There were no resveratrol synthesis in 0℃, the resveratrol raised and downed at 10℃, and maximum resveratrol synthesized and variation in 20℃. The UV-C treated immature ‘Kyoho’ grape had a high content of resveratrol in first day, and than kept on a steady state. The more mature the fruit was; the less synthetical capacity of resveratrol. ‘Honey red’ grape, treated with UV-C, synthesized more resveratrol than ‘Kyoho’ grape. Different variety influences the synthetical capacity seriously. ‘Kyoho’ grape with 1、12 or 24 hr hypobaric treatment （-730 mmHg） were indicated that the short hypobaric treatment is induce more syntheticcal capacity of resveratrol in grape. The longer the hot water treatment did the higher maximal content of resveratrol in ‘Kyoho’ grape. These results above demonstrated that ‘UV-C’ does could increase the content of resveratrol in grape, and influence by temperature amd variety directly. Many alternative abiotic stresses could induce resveratrol in grape, but need further examination in future.
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Lan, Li-Hua, and 藍麗華. "Enhancement of Hydrophilic Property on SU-8 Structures by UV/Ozone Treatment." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/61554959481774362727.
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