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1
Bechwati, Fouad. "Acoustics of activated carbon." Thesis, University of Salford, 2008. http://usir.salford.ac.uk/26573/.
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This thesis describes a study into how sound interacts with activated carbon, a material that exhibits adsorbing and desorbing properties. Adsorption is where molecules from the surrounding gas are attracted to the material microstructure and held in place by a weak physical attraction force named after the scientist van der Waals\ desorption is the opposite process. Activated carbons include a complex porous structure, with a large internal surface area, and a considerable adsorption capacity caused by free electrons in the deformed graphene layers. The process of adsorption and desorption is usually associated with energy exchanges, caused by transfers of heat between the adsorbate molecules and the adsorbent surface. The study of acoustic interactions with granular activated carbons at normal conditions makes the subject of this doctoral thesis. Two main physical phenomena were seen to accompany sound propagation through the material: (i) an increase in volume compliance which is assumed to be caused by a change in the density of the interacting gas, and (ii) excess absorption at low frequencies thought to be due to the energy lost in the adsorption/desorption hysteresis. For the former, measurements on the impedance of low frequency Helmholtz resonators reveal significant shifts in resonance when activated carbon is used as a porous liner in the backing volume. At constant aperture dimensions, these shifts are attributed to a larger apparent volume of the resonator as compared to an empty backing volume. This phenomenon is in direct contravention of the physical theory associated with Helmholtz resonators as the resonant frequency of a device increases slightly when a porous solid is placed in the backing volume. An upper frequency limit of SOOHz is also determined where sorption effects in activated carbon are assumed to become almost negligible in relation to sound propagation. For the latter, the excess absorption at low frequency, a series of experiments to reveal the physical cause of the phenomenon have been undertaken. Hysteresis was observed during the sorption of humid air onto activated carbon at room temperature. At such conditions, the different rates of adsorption and desorption lead to a disturbance in the system equilibrium and cause a change in entropy. The return of the system to equilibrium is an exothermic process hence involves energy losses between activated carbon and the surrounding gas. This is suggested as a possible cause of the excess attenuation. However,the relaxation times are rather long for acoustic propagation, and further work is needed to examine this. An experimental apparatus to explore sound propagation through the material was devised. Results showed a violation of the equation of state for the relationship between volume and pressure: as the volume in a sealed chamber was reduced at constant temperature, the measured pressure change was found to be lower for a sample of activated carbon than when the chamber was empty; a phenomenon assumed due to the differences between adsorption and desorption rates. A new method for determining the porosity of a material exhibiting adsorption at acoustic pressures has been devised and found to be 81 ±7% for the granular sample examined. BET analysis and examination of electron microscope pictures allowed the pore size distribution to be found. Although the activated carbon sample has many very small pores (0.7nm in width), the BET isotherm showed that these will be saturated with water vapour in normal conditions. Consequently, the pores that affect sound propagation are those between the grains of the activated carbon, and the macropores (>50nm) on the surface of the grains. A theoretical model is developed and outlined based on the Langmuir isotherm. This was used to predict the sound propagation within the material and is compared to acoustic impedance measured in a large low frequency impedance tube, which was constructed especially for this project. The match between theory and measurement is rather poor, thought to be due to the lack of modelling the hysteresis effects in the adsorption- desorption cycle. Two applications of the material are examined, within a Helmholtz resonator and the cups of hearing defenders. In both cases, improved performance is seen. For instance, the use of the material in hearing defenders showed that activated carbon could be used to improve the attenuation at low frequencies in comparison to conventional foam liners.
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Chinn, Matthew. "The impregnation of activated carbon." Thesis, University of Huddersfield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247377.
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This thesis describes a study into the impregnation of activated carbon. A wide selection of commercially available activated carbons were impregnated with triethylaminediamine (TEDA). The utilisation of this impregnant was measured using custom built dynamic filtration apparatus. A discussion of the influence of carbon morphology and affinity for water vapour on impregnant utilisation is given. Purpose built adsorption apparatus enabled the first recorded isotherms of TED A on activated carbon to be measured. The isotherms allowed the location of the impregnant TED A in activated carbons to be determined. The majority of TEDA was shown to be located within the micropore region but at high partial pressure mesopore adsorption also took place. This apparatus was further used to control the rate of impregnation by varying temperature. By assessing the utilisation of TEDA on samples impregnated at different rates it was demonstrated that a low rate of impregnation is beneficial. Possible reasons for this observation are proposed. The use of novel metal doped carbons for hydrogen cyanide (HeN) adsorption was also investigated as part of this study. The carbons were prepared by co-workers at the University of Huddersfield who used ion-exchange of sodium carboxymethylcellulose with various transition metals prior to carbonisation and activation. Assessment of these materials required the adaptation of inverse gas chromatography and the construction of new apparatus capable of assessing the filtration performance of very small scale (~ 10 mg) powdered samples. The subsequent assessment of samples enable iterative improvement of the performance of these materials. These metal doped carbons were shown to possess a high capacity for HeN which was attributed to the high dispersion of metal within the activated carbon matrix. This work resulted in the granting of a patent for novel metal doped carbons for HeN removal. Further studies with metal impregnants on activated carbon included the optimisation of cobalt acetate/TEDA formulations in order to promote adsorption of HeN and cyanogen chloride. This resulted in the observation of synergy between different impregnant species on activated carbons.
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Zhang, Tengyan. "Preparation and characterization of carbon molecular sieves and activated carbons /." Search for this dissertation online, 2004. http://wwwlib.umi.com/cr/ksu/main.
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Zhang, Yan. "Carbon Dioxide Capture: Using Activated Carbon From Chicken Waste." TopSCHOLAR®, 2007. http://digitalcommons.wku.edu/theses/390.
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Carbon Dioxide (CO2) emission from hydrocarbon fuel combustion is becoming a serious concern because it is the main contributor to greenhouse gas which causes global warming. Activated carbon sorbents have been used widely in various gas-phase and/or liquid-phase separation. Currently activated carbon (AC) is being investigated and developed for CO2 capture. Chicken waste, which is produced in large quantity in U.S., is currently disposed as waste. However, it may have a large benefit to turn chicken waste into useful activated carbon. In this research, a series of activated carbon have been generated from chicken waste and coal in the lab scale reactor. The characteristics of these generated activated carbons, such as specific surface, thermal stability, structure properties were investigated and discussed. The CO2 adsorption capabilities of these activated cartons were also studied in pure CO2 system and CO2/H2O system. One of these activated carbons was modified using the acid treatment, which improved the CO2 adsorption capacity by around 4 times.
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Silvino, Pedro Felipe Gadelha. "Virtual models applied to activated carbon characterization." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13357.
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AgÃncia Nacional do PetrÃleoActivated carbons are amorphous materials represented by a pore size distribution (PSD) which usually reproduce the experimental isotherm of N2 at 77 K. Presently, we obtain this distribution using the activated carbon slit-pore model and isotherms calculated by molecular simulation. In this study, we have evaluated the extent to which the use of more realistic activated carbon models influences on the characterization, as well as the possibility of representing the activated carbon by a minimum three-pore PSD. Adsorption isotherms were calculated using the Grand Canonical ensemble within the Monte Carlo method, and compared with experimental isotherms of commercial activated carbons. The deconvolution method with non negative least squares was used to determine the PSDs. We observed that the models containing heterogeneity factors were more accurate than the simplified models, and that activated carbons could be well represented by a minimum three-pore distribution without significant loss of precision. Furthermore, we demonstrated that the minimum PSD could be applied to formulate virtual porous carbon models that are useful in the heterogeneity study. Finally, we propose the use of the minimum PSD to replace the classical calculations of average pore size.
Carbonos ativados sÃo materiais amorfos representados por uma distribuiÃÃo de tamanho de poros (PSD) que usualmente reproduz a isoterma experimental de N2 a 77 K. Presentemente esta distribuiÃÃo à obtida com o uso do modelo de carbono ativado de placas paralelas de grafeno e isotermas calculadas por simulaÃÃo molecular. Neste estudo avaliou-se a influÃncia do uso de modelos de poros de carbono ativado mais realistas sobre a caracterizaÃÃo, bem como a possibilidade de representar o carbono ativado por uma PSD mÃnima constituÃda de apenas trÃs poros. Isotermas de adsorÃÃo foram calculadas utilizando-se o algoritmo de Monte Carlo no ensemble grande canÃnico e comparadas com as isotermas experimentais de carbonos ativados comerciais. O mÃtodo de deconvoluÃÃo com mÃnimos quadrados nÃo negativos foi utilizado para determinaÃÃo das PSDs. Observou-se que modelos contendo fatores de heterogeneidade mostraram-se mais precisos que os modelos simplificados. Notou-se ainda que efetivamente o carbono ativado pode ser representado por uma PSD mÃnima de trÃs poros sem perda significativa de precisÃo. AlÃm disso, demonstrou-se que a distribuiÃÃo mÃnima pode ser usada para elaborar modelos virtuais de carbono que sÃo Ãteis no estudo de heterogeneidades. Finalmente propomos o uso da PSD mÃnima em substituiÃÃo ao cÃlculo clÃssico de tamanho mÃdio de poros.
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Bajracharya, Asnika Bajracharya. "Removal of Microcystin-LR Using Powdered Activated Carbon: Effects of Water Quality and Activated Carbon Property." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500594334891353.
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Reddy, Reddy Pratyusha. "Comparative Study of Adsorption of Dyes onto Activated Carbon and Modified Activated Carbon by Chitosan Impregnation." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1525171939645615.
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Holmes, Richard James. "Chemical modification of activated carbon adsorbents." Thesis, Brunel University, 1991. http://bura.brunel.ac.uk/handle/2438/5378.
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Activated carbons have been modif fed using reactive chemicals to produce adsorbents of enhanced hydrophobic character which will also be resistant to surface oxidation that results from exposure to humid air ("ageing"). The intention was that modification would not disrupt the carbon pore structure. The adsorptive properties of the modified carbons have been investigated using probe molecules Including nitrogen, water, hexane, and chloropicrin, and the ageing characteristics of the carbons, and the factors controlling the adsorption of a model hydrophobic vapour from high humidity air have been studied. Directly fluorinated carbons were unstable, probably due to weakly adsorbed fluorine. Treatment of these adsorbents with other chemicals indicated the potential of the technique for Introducing specific functional groups onto the carbon surface. Carbons modified using selective fluorinating reagents (hexafluoropropene and 1,1-difluoroethene) were more hydrophobic, and adsorbed hydrophobic vapours more efficiently from humid air in comparison to controls. These adsorbents aged, but at a reduced rate in comparison to control carbon. Carbons modified using chlorinating reagents (carbonyl chloride and chlorine) and treated with solvents to remove adsorbed reagent and/or reaction products were of improved hydrophobic character, and adsorbed hydrophobic vapours from humid air at least as efficiently as the control samples. More importantly, these carbons offered resistance to ageing effects. A study of the factors controlling the efficiency with which hydrophobic vapours; are adsorbed from humid air revealed that the surface chemistry of the carbon is important, but that under typical conditions of use, filter performance was limited by the rate at which water displaced by the organic vapour could be carried away by the airstream. The results illustrate that filters containing chemically modified activated carbon offer advantages when volatile hydrophobic contaminant vapours are present, and where ageing effects are an important mechanism by which filtration efficiency is degraded.
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Karimi-Jashni, Ayoub. "Electrochemical reactivation of granular activated carbon." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6200.
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The main objectives of this dissertation were to refine electrochemical GAC reactivation technology, a promising alternative technology, and to investigate its technical feasibility. The specific objectives of the study were: (1) to evaluate alternative reactor designs; (2) to assess the effect of contaminant and GAC types on the regeneration efficiency; (3) to study the electrolyte post-treatment; and (4) to investigate reactivation mechanisms and model them. To achieve these objectives many interrelated topics were investigated using phenol, 2-nitrophenol (2NP) and naturally occurring background organic matter (NOM) as adsorbates and Filtrasorb 400 (F-400), Westvaco Carbon (WV-B), Darco Norit, and Filtrasorb 300 (F-300) as adsorbents. The impact of reactor operation conditions (reactivation time, current density, pH) on the reactivation efficiency showed that the reactivation efficiency (RE%) could be increased to a maximum by increasing the current and/or time. It was concluded that electrochemical reactivation of GAC is contaminant-type dependent. The reactivation efficiencies of F-400 loaded with 2NP and phenol at different reactivation currents and times showed similar patterns. A comparison of the percent reactivation of GACs showed that F-400 and WV-B performed essentially the same for the tested conditions. Total destruction of desorbed contaminants and their by-products were possible. Desorbed phenol and 2NP from loaded GAC react to form a number of reaction by-products that are eventually oxidized to CO2 and H 2O. The main mechanism responsible for electrochemical reactivation is high-pH induced desorption at the cathode. It accounts for approximately 50--60% of the total reactivation of a single layer of GAC. It is recommended that the GAC electrochemical reactivation should be a three step process. First, the GAC is reactivated with a relatively low current to minimize potential alterations of the GAC surface. Second, the GAC is drained and rinsed with a buffered solution. Finally, the electrolyte is treated electrochemically for an extended time at a much higher current (and possibly a different electrode) to reduce the electrolyte's TOC so that it may be reused or discharged. (Abstract shortened by UMI.)
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Cen, Jianqi. "Electrochemical regeneration of granular activated carbon." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6754.
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Laboratory experiments have investigated the feasibility of granular activated carbon (GAC) regeneration via an electrochemical technique. GAC was loaded with phenol by batch adsorption tests, electrochemically regenerated and finally reloaded with phenol. Regeneration was conducted by placing GAC on a platinum elecotrode within a batch reactor filled with electrolyte (generally a 1% NaCl solution), and applying a current to the reactor. Limited experiments show that cathodic regeneration is more efficient than anodic regeneration; the investigation concentrates on the former. Although anodic regeneration is more efficient in destroying residual phenol in the electrolyte, cathodic regeneration can also eliminate these residuals by using longer regeneration times and/or higher currents. Increasing the regeneration current and time could increase the regeneration efficiency (RE) up to 94 percent. Lower currents applied for longer regeneration times yield similar results with slightly lower energy consumption. REs are also significantly affected by the electrolyte type, electrolyte concentration, and GAC particle size, but not by the carbon loading. Multiple regenerations only reduced the REs by an additional 2 percent per cycle. Preliminary analysis indicates that electrochemical regeneration is less expensive than thermal regeneration as it has no obvious carbon losses. Since this electrochemical regeneration process is technologically feasible and probably more economical than thermal regeneration, it merits further investigation.
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Carvalho, Leslie Bosco. "Protein adsorption on powdered activated carbon." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415009.
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Rowe, Deborah Louise. "Biosorption of metals by activated carbon." Thesis, University of Bath, 1998. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760711.
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Zheng, Yishan. "Activated carbon & carbon-cryogel composites for haemoperfusion based applications." Thesis, University of Brighton, 2013. https://research.brighton.ac.uk/en/studentTheses/daf37d00-4da8-4b0d-8bb5-a91941fed23d.
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A number of pathological conditions are associated with the build up of toxic substances within the systemic circulation. For example, renal and hepatic failure can lead to the accumulation of metabolites which are usually processed by these organs. There has been much interest over a number of years in techniques such as haemoperfusion that could help clear these toxins from the body and improve patient outcome. Haemoperfusion is an extracorporeal blood purification technique in which a patient’s blood is passed over a column containing a material designed to adsorb a board spectrum of biological toxic molecules. Direct blood contact with the adsorbent requires a material that is able to display good haemocompatibility whilst maintaining adsorption efficiency. Activated carbons (AC) have great adsorption capacity and have previously been used as haemoadsorbents. However the haemocompatibility of carbons has been questioned and they are often coated with biocompatible polymers that increase their haemocompatibility but also act as a barrier to the removal of larger toxins and middle molecules.
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Walker, Gavin Michael. "Industrial wastewater treatment using biological activated carbon." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295433.
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Rahman, Anuar Abdul. "Chemically activated carbon for flue gas scrubbing." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284978.
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Murki, Sai Rohith, and Yaswanth Puttagunta. "CFD Simulation of an Activated Carbon Filter." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13839.
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In various industries, specialized filters with activated carbon are used for adsorbing mercury from air-flows. MRT has eight such Activated CarbonFilters (ACFs) in one of their devices. The main purpose of research is tostudy the flow in the ACF filter and suggest a mathematical model for the complete system through which an improved design can be found.Simulation of a single ACF illustrates how the current system’s air flow does not cover the whole filter leaving part of the carbon bed unused forthe adsorption. This is validated by experimental data. A theoretical studybased on a mathematical model is made and the improved air flow pattern of a re-designed ACF is presented. An additional improvement is that byswitching inlet and outlet the usable time of the filters is prolonged.
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Smith, Bartina Ciara. "Adsorption of Denatonium Benzoate Using Activated Carbon." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1304684769.
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Rossi, Giovanni E. "Phosgene formation over an activated carbon catalyst." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/16187/.
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The production of phosgene typically involves the gas phase reaction between carbon monoxide (CO) and dichlorine (Cl2) in the presence of an activated carbon catalyst. The first stage of the study investigated the kinetics of phosgene formation over a high surface area carbon catalyst. This included determining a rate law and an activation energy for the reaction. A reaction mechanism is proposed based on the experimental observations.
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Kramer, Mark John. "Azo Dye Removal from Wastewater Streams Via Organophilic Clay Adsorption." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin975422451.
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Birbas, Daniella. "Preparation of Activated Carbon: Forest residues activated with Phosphoric Acid and Zinc Sulfate." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33274.
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Activated carbon is a highly adsorbing material and has various scopes of uses depending on needs. It is used in many industries and applications e.g. to clean industrial wastewater, in medicine, discolor sugar and so on. What makes AC such a good adsorbent is its porous structure which gives it a high surface area. This report consists of three parts; general information about Activated Carbon (AC) and its characteristics, to give the reader a sufficient background about AC for continuous understanding throughout the report, an experimental investigation in chemical activation of carbon with phosphoric acid as the chemical reagent and sawdust from both Cuban and Swedish Pine tree as precursors, and a second experimental investigation in chemical activation of carbon with Zinc Sulfate as the chemical reagent and sawdust from Cuban Pine tree as the precursor. For the first experimental part as well as for the second the objective is how to best combine the three parameters; acid concentration, impregnation ratio and activation temperature in order to get the best adsorption performance when preparing activated carbon with different precursor specimens and chemical reagents. The experiments with phosphoric acid activation show that treatment with 40% acid concentration at 400 °C produce an activated carbon with good properties for ammonia adsorption and good iodine number. If a 30% phosphoric acid is used for activation, an activation temperature of 500 °C is recommended. With an impregnation ratio of 1, good adsorption was obtained in the activated carbon produced from Swedish pine while using Cuban pine a higher adsorption was obtained with an impregnation ratio of 2. The experiments with Zinc Sulfate activation show that influence of the sulfate concentration (between 10 % and 40 %) and temperature (between 400 °C and 500°C) on the properties for ammonia adsorption in the produced activated carbon was considerable for low impregnation ratio (0.5 and 1). In general, activation conditions of 20% zinc sulfate concentration, 400 °C and impregnation ratio: 1 are enough to produce an activated carbon with good properties for ammonia adsorption. The adsorption of carbon tetrachloride was lower. Activated carbons produced with 10 % zinc sulfate concentration, 0.5 impregnation ratio and 400 °C activation temperature (the mildest studied conditions) show already good iodine number and BET surface area. The main conclusion from the thesis work is that the optimal conditions vary widely with wanted results. Therefore a suggestion for future work is to narrow the research to fewer variables and more repetition of the samples.
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Tamakloe, Senam. "Novel Synthesis of Bulk Nanocarbon (BNC)." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/99289.
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Carbonized organic precursors such as wood, shells and some plant seeds are very porous. They are nanostructured and tend to be hard, but have pure mechanical properties as a result of their porosities. An attempt was made to carbonize an organic precursor to produce a bulk material with much less porosity for possible use in structural applications such as reinforcement in metal and polymer matrices. A bulk nanocarbon (BNC) material was synthesized using high energy ball milling and the carbonization of corn cob. Corn cob was mechanically milled for up to 20 hours by applying high energy ball milling to produce the milled powder. The milled powder was cold-compacted and carbonized at up to 1500°C to fabricate the BNC material. The material revealed both micro and nano-porosities; the porosities decreased with carbonizing temperature and hold time. Micropores were mostly closed for samples carbonized above 1300oC, whereas they formed interconnected network at lower carbonization temperatures. BNC has a young's modulus of 120 GPa, about ten times that of extruded graphite.Master of Science
Wood, shells, and plant seeds are examples of organic precursors. When organic precursors are carbonized, they can become very porous, nanostructured, and hard, but deliver pure mechanical properties because of their porosities. A selected organic precursor was carbonized, in an attempt, to produce a bulk material with much less porosity for possible use in structural applications such as reinforcement in metal and polymer matrices. A bulk nanocarbon (BNC) material was made using high energy ball milling and the carbonization of corn cob (the selected organic precursor). This bulk material revealed both micro and nano-porosities, and a young's modulus of 120 GPa, about ten times that of extruded graphite.
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Sze, Fan Fu. "Enhanced abatement of aqueous organic compounds using stratified activated carbon adsorption columns /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CBME%202009%20SZE.
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Van, Pelt Adam Henderson. "Stability of acid-modified activated carbons in hot liquid water and their application to biomass hydrolysis reactions." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52024.
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In this work, the stability of acid-modified activated carbons is assessed in the typical biomass conversion reaction environment of 200 °C, 17 bar water. Activated carbons were modified with a variety of common liquid and gas phase methods and characterized. Acid-modified carbon catalysts were exposed to hot liquid water for 24 h and further characterized to determine the effect of this exposure on their surface chemistry. It was found that the liquid phase acidifying agents of H₂SO₄ and HNO₃ are most effective at adding acidic functionalities to the carbon. Exposure to hot liquid water was found to significantly decrease the carboxylic and sulphonic acid site concentrations on the carbons and slightly increased lactonic group concentrations. Kinetic studies indicate that these surface chemical changes occur within the first 4 h exposure to this environment, and that increased exposure temperature results in more efficient acid site removal. XPS measurements show that H₂SO₄ modification imparts partially stable sulfonic acid groups on the carbon surface while HNO₃ modification imparts nitro groups which are unstable at exposure temperatures above 150 °C. The second part of this work focuses on the application of these acid-modified activated carbon catalysts as well as a variety of mixed metal oxide catalysts to the hydrolysis of the model biomass compound cellobiose. Catalyst screening reactions indicate that amorphous silica alumina catalysts are stable and selective but only slightly active whereas silica niobia catalysts are highly active but less selective and stable. Modified activated carbon catalysts were found to have moderate activity and selectivity. An investigation into the mechanism of silica niobia deactivation was performed and apparent activation energies were found for cellobiose hydrolysis over a variety of mixed metal oxide catalysts. Finally, a novel activated carbon synthesis mechanism was developed based on knowledge of surface site stability. This carbon catalyst was found to be highly active, selective, and stable for cellobiose hydrolysis but further characterization is required to fully understand its effectiveness as a catalyst.
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Callura, Jonathan C. "Activated carbon catalyzed nitrosamine formation via amine nitrosation." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52200.
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Nitrosamines have garnered increasing attention from researchers and policy makers in recent years due to potential human health implications associated with their unintentional formation in water and wastewater treatment facilities. This work addresses a crucial nitrosamine formation pathway concerning the catalysis of amine nitrosation by activated carbon materials whose use is widespread in municipal and industrial systems. Experimental results show that this catalysis is highly pH dependent, with maximum formation achieved near the pKa value for each of the secondary amines tested. This result suggests that the overall formation potential is governed by individual amine properties and their interactions with carbon surfaces, rather than solely nitrite speciation as previously reported. Formation of the most commonly studied nitrosamine, N-nitrosodimethylamine, was shown to be highly dependent on initial dimethylamine (DMA) solution concentration, with yields of approximately 0.11% of the spiked secondary amine at pH 7.5. Morpholine and dibutylamine, larger and bulkier secondary amines, formed their corresponding nitrosamines at higher yields than DMA (0.21% and 1.69%, respectively). Additionally, select tertiary amines were shown to be capable of undergoing nitrosation on the same order of magnitude as the secondary amines under neutral conditions in the presence of activated carbons. The magnitude of these results indicates that greater attention should be paid to this previously overlooked mechanism for nitrosamine formation.
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Covington, Brett A. "Activated carbon cloth regeneration with electrical resistance heating." Thesis, Monterey, California. Naval Postgraduate School, 1995. http://hdl.handle.net/10945/25649.
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Shaw, Jonathan. "NMR studies of adsorption processes upon activated carbon." Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4827/.
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This thesis is concerned with the adsorption behaviour of adsorbate molecules upon activated carbon. Limitations in bulk gravimetric measurements mean that the mechanism of adsorption for adsorbates upon carbonaceous materials is poorly characterised. The information obtained from NMR experiments performed upon the adsorbate molecules is applied to provide additional understanding of the adsorption process. A systematic study of a phosphate/phosphonate - adsorbent system is performed, and a theoretical basis for the results observed is discussed in terms of molecular mobility and the penetration of molecules into pores of differing sizes. Calculated pore volumes obtained from NMR data are discussed. It is demonstrated that phosphate and phosphonate molecules adsorb initially within larger pores at the surface of the adsorbent and subsequently progress deeper within the porous volume. The effects of magic-angle spinning and proton decoupling upon the adsorbate spectra obtained are also addressed. Relaxation measurements are used to study the motional freedom of adsorbed molecules and the measurements provide further corroboration to the interpretation of spectra expounded. The study is then extended to analyse the adsorption of adsorbate molecules upon carbon adsorbents with other adsorbate molecules pre-adsorbed. Analysis of spectra provides information upon the movement of both the primarily adsorbed material and secondary adsorbate within the pore volume. Preferential adsorption of phosphate molecules over water molecules is demonstrated. Finally, dynamic NMR techniques are used to characterise the exchange of adsorbate within the porous volume with excess adsorbate upon the exterior of the carbon adsorbent.
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Leyva-Ramos, Roberto, Raul Ocampo-Perez, Oliva L. Torres-Rivera, Maria S. Berber-Mendoza, and Nahum A. Medellin-Castillo. "Kinetics of pyridine adsorption onto granular activated carbon." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-191056.
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Leyva-Ramos, Roberto, Raul Ocampo-Perez, Oliva L. Torres-Rivera, Maria S. Berber-Mendoza, and Nahum A. Medellin-Castillo. "Kinetics of pyridine adsorption onto granular activated carbon." Diffusion fundamentals 11 (2009) 83, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A14054.
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Xia, Changlei. "Biomass-Derived Activated Carbon Through Self-Activation Process." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849716/.
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Self-activation is a process that takes advantage of the gases emitted from the pyrolysis process of biomass to activate the converted carbon. The pyrolytic gases from the biomass contain CO2 and H2O, which can be used as activating agents. As two common methods, both of physical activation using CO2 and chemical activation using ZnCl2 introduce additional gas (CO2) or chemical (ZnCl2), in which the CO2 emission from the activation process or the zinc compound removal by acid from the follow-up process will cause environmental concerns. In comparison with these conventional activation processes, the self-activation process could avoid the cost of activating agents and is more environmentally friendly, since the exhaust gases (CO and H2) can be used as fuel or feedstock for the further synthesis in methanol production. In this research, many types of biomass were successfully converted into activated carbon through the self-activation process. An activation model was developed to describe the changes of specific surface area and pore volume during the activation. The relationships between the activating temperature, dwelling time, yield, specific surface area, and specific pore volume were detailed investigated. The highest specific surface area and pore volume of the biomass-derived activated carbon through the self-activation process were up to 2738 m2 g-1 and 2.209 cm3 g-1, respectively. Moreover, the applications of the activated carbons from the self-activation process have been studied, including lithium-ion battery (LIB) manufacturing, water cleaning, oil absorption, and electromagnetic interference (EMI) shielding.
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Jaria, Guilaine Marques. "Adsorption of fluoxetine onto waste-based activated carbon." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13664.
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Mestrado em Química - Química Analítica e QualidadeActivated carbons are one of the most promising techniques for the removal of organic and inorganic compounds from waters. In this work three activated carbons were produced using as precursor primary paper mill sludge. Chemical activation was performed using three different activation agents, KOH, NaOH and ZnCl2, and the same pyrolysis conditions were applied. The characterization of the obtained materials was made by means of total organic carbon analysis (TOC), Fourier infrared spectroscopy with attenuated total reflectance (FTIR-ATR), proximate and ultimate analysis, scanning electron microscopy (SEM), Hg porosimetry, BET isotherms and point of zero charge (PZC) determination. Adsorption studies were made, beginning with adsorption kinetic and then adsorption equilibrium (isotherms of adsorption), all performed in batch experiments. Generally, the carbons presented an equilibrium time of around six hours. Equilibrium studies allowed test the adsorption capacity of the produced carbons for fluoxetine-HCl. These two studies were also performed to the primary sludge pyrolysed under the same conditions without activation and also to a commercial activated carbon as reference. Among the produced materials, the carbon activated with ZnCl2 has the higher BET surface area and percentage of carbon. The maximum adsorption capacity (mg g-1) was of 96.2 ± 1.0 for PBFG4; 120.4 ± 2.5 for PS800-10; 191.6 ± 4.8 for PS800-10KOH; 136.6 ± 9.6 for PS800-10NaOH; and 28.4 ± 0.3 for PS800-10ZnCl2. The isotherms obtained point for different mechanism of adsorption between the carbons, probably due to their distinct PZC.
Os carvões ativados são uma das técnicas mais promissoras para a remoção de compostos orgânicos e inorgânicos presentes nas águas. Neste trabalho, foram produzidos três carvões ativados utilizando como precursor lamas primárias residuais provenientes da produção de papel. Foi utilizada a ativação química com KOH, NaOH e ZnCl2, aplicando as mesmas condições de pirólise aos três carvões. A caracterização dos materiais obtidos foi feita por meio de análise de carbono orgânico total (TOC), espectroscopia de infravermelho com transformada de Fourier usando a técnica reflexão total atenuada (FTIR-ATR), Proximate and ultimate analysis, microscopia eletrónica de varrimento (SEM), porosimetria de mercúrio, isotérmicas BET e determinação do ponto de carga zero (PZC). Foram realizados estudos de adsorção iniciados pela cinética de adsorção e seguidos das isotérmicas, usando experiências em vaso fechado. Os estudos de cinética de adsorção mostraram que, na generalidade, todos os carvões produzidos apresentaram um tempo de equilíbrio semelhante, cerca de seis horas. As isotérmicas permitiram testar a capacidade de adsorção dos carvões produzidos para o composto fluoxetina-HCl. Estes dois estudos foram também aplicados à lama primária pirolisada sob as mesmas condições mas sem ativação e também a um carvão ativado comercial, usado como referência. Entre os materiais produzidos, o carvão ativado com ZnCl2 é o que apresenta uma área superficial específica (SBET) superior e maior percentagem de carbono. A capacidade máxima de adsorção (mg g-1) foi de 96.2 ± 1.0 para o PBFG4; 120.4 ± 2.5 para PS800-10; 191.6 ± 4.8 para PS800-10KOH; 136.6 ± 9.6 para PS800-10NaOH; e 28.4 ± 0.3 para PS800-10ZnCl2. As isotérmicas obtidas apontam para a existência de diferentes mecanismos de adsorção entre os carvões, provavelmente devido aos seus valores de PZC.
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Joiner, Matthew Charles. "Optimization of activated carbon for natural color removal." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025143.
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Sengupta, Aritra. "Intracellular drug delivery using laser activated carbon nanoparticles." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53996.
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We demonstrate intracellular delivery of various molecules by inducing controlled and reversible cell damage through pulsed laser irradiation of carbon black (CB) nanoparticles. We then characterized and optimized the system for maximal uptake and minimal loss of viability. At our optimal condition 88% of cells exhibited uptake with almost no loss of viability. In other more intense cases it was shown that cell death could be prevented through addition of poloxamer.
The underlying mechanism of action is also studied and our hypothesis is that the laser heats the CB leading to thermal expansion, vapor formation and/or chemical reaction leading to generation of acoustic waves and then there is energy transduction to the cell causing poration of the cell membrane.
We also delivered anti-EGFR siRNA to ovarian cancer cells. Cells exposed to a laser at 18.75 mJ/cm2 for 7 minutes resulted in a 49% knockdown of EGFR compared to negative control. We established an alternative way to deliver siRNA to knockdown proteins, for the first time using laser CB interaction.
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Awang, Abdul Rahman bin. "Seeded microfiltration of copper with modified activated carbon." Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/35238.
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In this study the use of seeded microfiltration (MF) with modified powdered carbon focussed on the removal of copper ions from an aqueous solution. The aim of the study was to look into the possibility of utilisation of suitable modified activated carbons combined with membrane filtration (microfiltration) as an alternative technique for the treatment and recovery of copper ions from liquid wastes, to give high removal efficiency with low energy consumption. To enhance the filtration process, the particle size of modified activated carbon used was small because it provides a larger surface area and a shorter diffusional distance for base metals to be adsorbed. Furthermore, in order to minimise the fouling effect, a surface filter (nickel membrane) which had pores, or slots, that passed directly from one side of the filter to the other with no tortuosity was used.
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Bergna, D. (Davide). "Activated carbon from renewable resources:carbonization, activation and use." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526224121.
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Abstract Biomass is the most abundant renewable material present on Earth and has been widely used e.g. in energy production. Recently, new applications for biomass utilization have been developed, e.g. the use of biomass as a raw material for synthesizing new chemicals. This research aimed to produce activated carbon (AC) from waste wood-based materials and peat through carbonization followed by physical or chemical activation. Physical steam activation and chemical activation generate the porosity in AC after the carbonization. The desired properties of AC (porosity, pore size distribution, surface functionality) are dependent on the application in which AC is used. The first part of the research focused on setting up the carbonization and activation device. The most important variables affecting carbonization and activation and the AC properties were studied. The process parameters were optimized through the design of experiments (DOE). The results showed that in the physical activation, the most important variables affecting the characteristics of AC are the holding time, temperature, and the steam feed. Consequently, a model for tailoring the microporosity or mesoporosity of AC and maximizing the yield is proposed. The second part of the research focused on chemical activation using zinc chloride. The aim was to study the effect of activation variables on the yield and properties of AC. Finally, the use of AC as an adsorbent was studied. Especially, the applicability of birch sawdust based activated carbon on the removal of dyes, zinc metal, nitrate, phosphate, and sulfate ions was evaluated. Based on the results, a difference was shown between one and two step process for carbonization and activation, and a single-step process was suggested to maximize the quality of ACTiivistelmä Biomassa on maapallon eniten saatavilla olevaa uusiutuvaa materiaalia, jota on hyödynnetty jo pitkään mm. energiantuotannossa. Viime aikoina uusia biomassan käyttökohteita on kehitetty laajalti, kuten esimerkiksi uusien kemikaalien valmistukseen. Tässä tutkimuksessa puupohjaista jätebiomassaa ja turvetta hyödynnetään fysikaalisesti ja kemiallisesti aktivoidun aktiivihiilen valmistuksessa. Fysikaalinen höyryaktivointi ja kemiallinen aktivointi lisäävät aktiivihiilen huokoisuutta hiilestyksen jälkeen. Aktiivihiilen halutut ominaisuudet (huokoskokojakauma, pinnan toiminnalliset ryhmät) määräytyvät käyttökohteen mukaan. Tutkimuksen ensimmäisessä vaiheessa keskityttiin hidas pyrolyysilaitteiston ja aktivointilaitteiston rakentamiseen sekä hiilestyksen ja aktivoinnin kannalta keskeisimpien muuttujien tutkimiseen. Prosessimuuttujien vaikutusten tarkastelussa ja optimoinnissa hyödynnettiin koesuunnitteluohjelmaa. Tulosten perusteella todettiin, että fysikaalisessa aktivoinnissa olennaisimmat muuttujat olivat lämpötila, pitoaika sekä höyrysyöttö. Tämän pohjalta esitettiin malli aktiivihiilen mikro- ja mesohuokoisuuden muokkaamiseksi ja saannon maksimoimiseksi. Tutkimuksen toisessa vaiheessa tutkittiin kemiallista aktivointia hyödyntämällä sinkkikloridia aktivointikemikaalina. Tavoitteena oli selvittää eri aktivointimuuttujien vaikutusta saantoon ja aktiivihiilen laatuun. Tutkimuksen viimeisessä vaiheessa tutkittiin valmistettujen aktiivihiilien käyttöä adsorbenttina. Erityisesti tutkittiin koivupurusta valmistetun aktiivihiilen soveltuvuutta väriaineiden, metallien ja anionien sidontaan. Tutkimuksen keskeisenä tuloksena voitiin osoittaa merkittävä ero yksi- ja kaksivaiheisen hiilestyksen ja aktivoinnin välillä, ja ehdotettiin yksivaiheista prosessia hiililaadun optimoimiseksi
Sommario La biomassa è il materiale rinnovabile più abbondante presente sulla Terra ed è stata intensamente usata e.g. nella produzione di energia. Recentemente sono state sviluppate nuove applicazioni per la biomassa, ad esempio come materiale di base per sintetizzare nuovi prodotti chimici. Lo scopo di questa ricerca è produrre carbone attivo (CA) attraverso attivazione fisica e chimica da materiali legnosi di scarto come segatura, cippato e torba. L’attivazione fisica e l’attivazione chimica, creano la porosità nel CA dopo la carbonizzazione. Il prodotto finale può essere usato in differenti applicazioni in base a diversi fattori tra cui la distribuzione della porosità e la tipologia dei gruppi funzionali presenti sulla superficie. La prima fase della ricerca è stata dedicata alla progettazione e installazione dell’hardware necessario per l’attivazione e nell’individuazione dei parametri di processo più importanti. I parametri di processo sono stati ottimizzati attraverso il design of experiments (DOE) e sono state considerate le differenti variabili che interagiscono nella formazione del CA. I risultati hanno mostrato che i parametri di processo più importanti che influiscono sulle caratteristiche del CA sono il tempo, la temperatura di attivazione e la quantità di vapore iniettato nel reattore. È stato proposto un modello per progettare CA microporoso o mesoporoso con massa finale massimizzata. La seconda parte della ricerca è stata incentrata sull’attivazione chimica con cloruro di zinco. Lo scopo é stato studiare l’effetto delle variabili di attivazione su massa finale e proprietà del carbone attivo. Infine, è stata studiato il CA come adsorbente. In particolare è stata considerata l’applicabilità del CA da segatura di betulla per la rimozione di coloranti, zinco metallico, ioni di nitrato, fosfato e solfato. In base a questi risultati, una differenza é stata evidenziata tra il processo di carbonizzazione e attivazione a uno o due stadi, ed il processo a singolo stadio è stato proposto per massimizzare la qualità del CA
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Contreras, Osmary C. "A comparative study of tailored activated carbon from waste tires against commercial activated carbon (F400) for the removal of Methylene Blue." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1383812437.
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Valente, Inês Alexandra Manata Antunes. "Adsorption equilibria of flue gas components on activated carbon." Master's thesis, Faculdade de Ciências e Tecnologia, 2014. http://hdl.handle.net/10362/12168.
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Almasoudi, Afaf. "Templated and activated porous carbon and carbon nitride materials for gas storage applications." Thesis, University of Nottingham, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659191.
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This Thesis details the synthesis, characterisation, and appl ications of micro/mesoporous carbon materials with tunable porosity prepared via template carbonisation. The main focus is the development of carbonaceous porous materials via for energy related gas storage applications. The Thesis investigates three synthesis strategies, namely; (i) nanocasting via liquid impregnation using zeolitic imidazolate framework (ZIF-8) as template, (ii) combination of liquid impregnation and chemical vapour deposition (CVD) using ZIF -8 as template and (iii) use of zeolite 13X and Y as templates for porous N-doped (carbon nitride type) materials. All the templated carbon materials were additionally activated to enhance their porosity and evaluated for gas (hydrogen and C02) storage.
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Huggahalli, Madhusudhan. "Steam regeneration of activated carbon beds : mechanisms and models /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Gibson, John Alastair Arran. "Development of functionalised porous carbon materials for the separation of carbon dioxide from gas mixtures." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25488.
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This work concerns the functionalisation of a variety of carbon materials for the selective adsorption of carbon dioxide. A key challenge in post-combustion capture from gas fired power plants is related to the low CO2 concentration in the flue gas (4- 8%). Therefore highly selective adsorbents have the potential to improve the efficiency of the separation of carbon dioxide from gas mixtures. The study was performed in conjunction with the EPSRC funded project ‘Adsorption Materials and Processes for Carbon Capture from Gas-Fired Power Plants – AMPGas’. The carbon materials investigated included multi-walled carbon nanotubes, a microporous activated carbon, two types of mesoporous activated carbon and multi-walled carbon nanotube/polyvinyl alcohol composite aerogels. The uptake of carbon dioxide by these materials was enhanced through the addition of basic amine groups to the materials. The adsorption properties of the samples were tested by the zero-length column technique, thermal gravimetric analysis and breakthrough experiments. The materials were generally tested at conditions representative of those found in the flue gas of a fossil fuel power plant: 0.1 bar partial pressure of CO2. Two approaches were adopted for the chemical functionalization of the solid carbon supports. First, amine groups were covalently grafted directly to the surface and secondly amine molecules were physically adsorbed within the porous structure of the material by wet impregnation. It was seen that wet impregnation enabled the incorporation of a greater number of amine groups and the CO2 capacity of the materials was investigated with respect to the carbon support structure, the type of amine and the amount of amine loading. Larger pore volume mesoporous carbon materials were seen to provide a more efficient support for the amine to interact with the CO2. A greater than 12-fold increase in the CO2 capacity was observed when the amine impregnated carbon material was compared to the raw starting material. The extended zero-length column was introduced and fully characterized as a novel breakthrough experiment. It requires a small sample mass (~50 mg) and it allows binary selectivities to be calculated. It was shown, through multiple experiments and simulations that the breakthrough experiments were conducted under close to isothermal conditions which greatly simplifies the analysis of the breakthrough curves. In addition, a new zero-length column model was proposed to account for the reaction between the amine and the CO2 in the adsorbed phase and fitted to experimental data. An interesting double curvature was observed in the concentration profile during the desorption step which was attributed to the kinetics of the amine-CO2 reaction. A brief investigation was carried out into the binary separation of biogas (45% CO2: 55% CH4) by zeolite 13X, activated carbon and an amine impregnated activated carbon. Finally, initial investigations into the properties of low density carbon nanotube aerogels which have a large accessible pore volume, were carried out. Their potential as highly efficient supports for amine impregnation was investigated. It was found that amine functionalized carbons strongly interact with carbon dioxide and have the potential to be integrated as an adsorbent in a rapid temperature swing process that separates carbon dioxide from dilute gas streams.
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Solbra, Susan Tanja. "Development of a device for monitoring metal pollutants in seawater." Thesis, University of Brighton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369713.
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Teirlinck, Peter Albert Maria. "The adsorption of gold from iodide solutions." Thesis, Cape Technikon, 1996. http://hdl.handle.net/20.500.11838/885.
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Thesis (Masters Degree (Chemical Engineering)) - Cape Technikon, Cape Town, 1996With the increasing awareness ofpreserving the environment, the need for other lixiviants in leaching processes has escalated. The investigation for lixiviants, especially for gold, has entailed mostly the halogen group. From halogens, iodine forms the most stable gold complex. The aim ofthis study was to investigate the adsorption characteristics of gold-iodide onto a coconut shell based activated carbon. In the first part of this study, the factors influencing the adsorption kinetics and equilibrium were investigated. Mixing experiments and interruption tests indicated clearly that the principal adsorption mechanism is by first order film diffusion. When the initial gold concentration was changed, the adsorption kinetics and equilibrium decrease viith an increase in gold concentration. This is due to the shielding effect by the adsorbed gold as it is partly reduced on the carbon surface. The concentration of iodide increased the adsorption kinetics and equilibrium. The increase in concentration of iodine leads to an increase in concentration ofthe principal oxidising agent, tri-iodide, thereby decreasing the adsorption parameters as the gold gets redissolved from the carbon surface. Furthermore, iodine and trio-iodide adsorbs competitively, thereby decreasing the rate ofadsorption ofthe gold complex. This is further iterated by experiments where the carbon was pre-treated v.ith a iodine/iodide solution. In acidic solutions, none, or a minimal amount ofthe gold is red11ced on the carbon surface, adsorption is only in the complex form, while in a alkaline solution, the gold is partly adsorbed and partly reduced. In the second section, the adsorption is approached from a basic electrochemical perspective. Here, depending on the pH ofthe solution, it is shown that the potential ofthe solution dictates the species of iodine and gold-iodide complex in solution, it affects the adsorption characteristics ofthe activated carbon.
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Morley, Matthew Christopher. "Enhanced desorption : a method for off-line bioregeneration of granular activated carbon loaded with high explosives /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Yeung, Kit Ying. "Production and characterization of activated carbon from waste tyre char by steam activation /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CBME%202009%20YEUNG.
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Graham, Brian Robert. "Comparison of powdered activated carbon and activated sludge treatment of a kraft pulp mill wastewater." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/10257.
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The Powdered Activated Carbon Treatment$\rm\sp{TM}$ (PACT$\rm\sp{TM})$ process consists of powdered activated carbon addition to the activated sludge treatment process. Objectives were (1) to compare treatment of kraft pulp mill wastewater using activated sludge versus PACT$\rm\sp{TM},$ by measuring toxicity, organic load, adsorbable organic halides (AOX) and metals and (2) to assess how three operating conditions: (1) carbon dose; (2) hydraulic retention time; (3) solids retention time, affected performance. Findings were: (1) Lengthy hydraulic retention times are unnecessary. Short hydraulic retention times (4 h) provide adequate treatment. (2) Activated sludge treatment alone removes most biochemical oxygen demand, PACT$\rm\sp{TM}$ offers no improvement. PACT$\rm\sp{TM}$ improves removal of soluble chemical oxygen demand. PACT$\rm\sp{TM}$ improves removal of AOX. Powdered activated carbon dose is the sole determinant of this increased removal. (3) Activated sludge treatment alone removes Microtox$\rm\sp{TM}$ toxicity. PACT$\rm\sp{TM}$ slightly improves treatment of highly toxic wastewaters. Significant chronic toxicity towards Ceriodaphnia remains in effluents from both activated sludge and PACT$\rm\sp{TM}.$ Both treatments remove toxicity to Ceriodaphnia, but PACT$\rm\sp{TM}$ effluents are more toxic. Powdered activated carbon alone exhibits toxicity to Ceriodaphnia. (4) The effect of PACT$\rm\sp{TM}$ on removal of metals is inconclusive. (5) PACT$\rm\sp{TM}$ treatment of kraft mill wastewater would be very expensive. (6) PACT$\rm\sp{TM}$ has limited benefits over activated sludge for the treatment of kraft mill wastewater, therefore PACT$\rm\sp{TM}$ is not recommended for treatment of kraft mill wastewater.
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Peredo, Mancilla Joselin Deneb. "Adsorption and Separation of Carbon Dioxide for Biomethane Production : The Use of Activated Carbons." Thesis, Pau, 2019. http://www.theses.fr/2019PAUU3012/document.
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Le biométhane est une source d'énergie verte qui, de part son coût et son faible impact environnemental, peut être considéré comme une alternative au gaz naturel et au diesel. La production d'énergie primaire par l'Union Européenne, à partir du biométhane, a été multipliée par 23 en cinq ans (2011-2016), ce qui rend nécessaire et urgent la recherche de nouvelles solutions performantes pour l’épuration du biogaz, notamment la séparation du dioxyde de carbone (CO2) du méthane (CH4).Dans ce contexte, l’objectif de ce travail doctoral porte sur la détermination des indicateurs de performances (capacité d’adsoprtion, sélectivité) de charbons actifs (CAs) dans le contexte de la séparation méthane/dioxyde de carbone pour la production de biométhane. A cette fin, les isothermes d'adsorption de CH4 et CO2 ont été déterminées à partir d’un dispositif manométrique d’adsorption. Les mesures ont été effectuées à des températures de 303 et 323 K pour des pressions variant de 0.1 à 3 MPa. Dans un premier temps, l’étude a porté sur 5 échantillons commerciaux de CA différents. Les résultats montrent une corrélation entre la surface spécifique et la quantité de dioxyde de carbone adsorbée. En outre, le volume microporeux a un impact significatif lors des processus d'adsorption du CO2 tandis que le volume des mésopores n'a pas d’effet direct.Par ailleurs, l'étude complémentaire d'isothermes d'adsorption du CH4 et du CO2 purs à l’aide de trois charbons actifs, issus de noyaux d’olive, activés par différentes méthodes de synthèse, révèle que la méthode d'activation est déterminante pour modifier les propriétés chimiques et structurales des charbons actifs et donc accroitre leurs propriétés d'adsorption.En outre, la sélectivité des CAs commerciaux pour la séparation CH4/ CO2 a été calculée à partir des isothermes d'adsorption du mélange équimolaire CH4/ CO2 à une température de 303 K et pour des pressions jusqu'à une pression de 3 MPa. Les résultats obtenus montrent qu’une surface spécifique élevée (< 1500 m2 g-1) facilite l'adsorption du CO2 mais réduit le facteur de sélectivité. En parallèle, une forte porosité conduit à une séparation moins efficace des deux gaz alors que la présence de groupes basiques en surface favorise les phénomènes d’adsorption du CO2.L'ensemble des résultats montre que les charbons actifs, étudiés dans ce travail de recherche, possèdent des propriétés d'adsorption comparables à celles des charbons actifs commerciaux et sont des matériaux compétitifs pour l'épuration du biogazBiomethane is a proven source of clean energy, it is one of the most cost-effective and environment-friendly substitute for natural gas and diesel. The European Union primary energy production from biomethane has folded by ~23 times in a 5 years time period (2011-2016) making necessary to find new and improved solutions for the separation of methane (CH4) and carbon dioxide (CO2), main components of biogas. In this context, the objective of this doctoral thesis is the determination of performance indicators such as the adsorption capacity and selectivity of activated carbons (ACs) for the CH4/ CO2 separation. This work focuses on the adsorption properties of activated carbons for the methane/carbon dioxide separation. To this end, CH4 and CO2 pure gas experimental adsorption isotherms of activated carbons were obtained on a pressure range of 0.1 to 3 MPa) and temperatures ranging from 303 to 323 K. The first part of this thesis project consisted in the analysis of the CH4 and CO2 pure gas adsorption properties of 5 commercial activated carbons Using a set of five commercial activated carbons a linear relationship between the adsorbent surface area and the CO2 adsorption capacity was determined. The micropore volume also showed a direct influence on the adsorption capacity. The second part of this work consisted in the study of the carbon dioxide and methane adsorption behavior of biomass-based activated carbons. Using a series of 3 ACs that had been obtained from olive stones by different activation methods, the activation technique proved to be of mayor importance as it determines the textural and chemical properties of the adsorbent and thus its gas adsorption capacity.Lastly, the CH4/CO2 adsorption selectivity of the 5 commercial activated carbons was calculated from the equimolar mixture adsorption isotherms. The selectivity factor was proven to be dependent on the sum of textural and chemical properties of the samples. Although, activated carbons with high average pore sizes and surface areas depicted higher adsorbed quantities it was on detriment of their selectivity. The selectivity was found to be better for the activated carbon showing an intermediate surface area and a narrow pore size distribution. In addition, the presence of sulfur functionalities was also found to improve the adsorption selectivity. Overall, this work shows that activated carbons are competitive materials for the upgrading of biogas, displaying adsorption properties comparable to those of other commercially available materials
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Liang, Ying. "Formation of continuous activated carbon fibers for barrier fabrics." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/8599.
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Valente, Nabais Joao, and Peter Carrott. "Chemical Characterisation Of Activated Carbon Fibres And Activated Carbons." Bachelor's thesis, 2006. http://hdl.handle.net/10174/3863.
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The objective of this laboratory is the chemical characterization
of carbon materials using several methods to obtain
information without using expensive instruments.
During this lab the students determine the potential of zero
charge (pzc) by mass titrations and quantify the acidic and
basic sites by acid–base titrations.
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Boor, Richard L. "Adsorption and activated carbon." 1992. http://catalog.hathitrust.org/api/volumes/oclc/32290194.html.
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Ya, Yu-chiang, and 葉雲強. "Study on Adsorption of Acetaldehyde onto Impregnated Activated Carbon and Activated Carbon Cloth." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/51160936931561120750.
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碩士雲林科技大學
化學工程與材料工程研究所
96
The aim of this thesis is to investigate adsorption capacity of acetaldehyde on activated carbon (AC) and activated carbon cloth (ACC) before and after modification. Both coconut shell based AC and phenolic resin based ACC were studied. Both AC and ACC were modified by different nitrate solutions included magnesium nitrate and cobalt nitrate. The impregnated AC and ACC were thermally treated at different temperature for different period. A nitrogen adsorption apparatus was used to measure the specific surface area, pore size distribution, and pore volume of the AC and the ACC. A scanning electron microscopy (SEM) was employed to observe surface morphology of the adsorbents. A Fourier transform infrared spectroscopic (FTIR) was employed to determine the functional groups on the surface of the adsorbents. An X-ray diffraction instrument was employed to determine crystallization of loaded metal oxide compound. A static volumetric method was applied to determine adsorption isotherms of acetaldehyde on the ACs and the ACCs. Experimental results showed that the pore volume of the untreated-ACC is larger than that of the untreated-AC. The adsorption capacity of acetaldehyde on the untreated-ACC is therefore larger than that on the untreated-AC. The adsorption capacities of both ACC and AC modified by magnesium oxide and cobalt oxide are larger than those of both untreated ACC and AC, respectively. Both Freundlich and Langmuir equations were used to simulate experimental isotherm data. The pseudo-first-order and the pseudo-second-order models were applied to fit experimental kinetics data. It was found that the Langmuir isotherm and the pseudo-second-order kinetic model fitted the experimental data very well.
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JIAN, DA-WEI, and 簡大濰. "Adsorption Characteristic Study of Areca Catechu Trunk Activated Carbons and a Commercial Activated Carbon." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/97074943572834768556.
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碩士國立聯合大學
環境與安全衛生工程學系碩士班
104
Activated carbons were prepared from Areca catechu trunks via ZnCl2 and KOH chemical activation methods. The adsorption characteristics of activated carbons were studied and compared with a commercial activated carbon F300. In the acid activation method, Areca catechu trunk chips were immersed in ZnCl2 aqueous solutions (ZnCl2/ Areca catechu trunk chip= 1、1.5、2、2.5 by weight) and dried. Then the chips were activated at different temperature (450, 500 and 550℃) for 20 minutes and were treated with hydrochloric acid. In the base activation method, Areca catechu trunk chips were carbonized at 450℃ for 1.5 hr. The carbonized chars were steeped in KOH aqueous solutions (KOH/ char= 2、3、4 by weight) and were activated at 780℃ for 1 hr. The physical and chemical properties were measured by BET specific surface area analyzer and elemental analysis. Three simplified models including the Intraparticle diffusion mode, Pseudo-second-order, and Elovich equation were used to investigated the adsorption kinetics of activated carbon for dyes (MG, MB, BB1, AB74) and phenols (4-CP, 4-cresol, phenol, 2,4-DCP, 4-BP). The adsorption kinetics was best fitted with the Pseudo-second-order model. Langmuirand and Freundlich isotherm equilibriums were used to analyzed the adsorptions of dyes and phenols.