Academic literature on the topic 'Process adsorption mechanisms'
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Journal articles on the topic "Process adsorption mechanisms"
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Huang, Fei, Lu Zhang, Ren-Ren Wu, Si-Ming Zhang, and Rong-Bo Xiao. "Adsorption Behavior and Relative Distribution of Cd2+ Adsorption Mechanisms by the Magnetic and Nonmagnetic Biochars Derived from Chicken Manure." International Journal of Environmental Research and Public Health 17, no. 5 (March 2, 2020): 1602. http://dx.doi.org/10.3390/ijerph17051602.
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The present study investigated the adsorption of Cd2+ by nonmagnetic and magnetic biochars (CMB and M-CMB) derived from chicken manure, respectively. The adsorption characteristics were investigated as a function of initial pH, contact time, initial Cd2+ concentration and magnetic separation. Adsorption process of both biochars were better described by Pseudo-second-order kinetic equation and Freundlich isotherm model, which were spontaneous and endothermic in nature. It was found that maximum capacities were 60.69 and 41.07 mg/g obtained at the initial Cd2+ concentration of 180 mg/L for CMB and M-CMB, and the turbidity of adsorption-treated solution was reduced from 244.3 to 11.3 NTU after magnetic separation of 0.5 min. These indicated that M-CMB had lower adsorption capacity of Cd2+ than CMB, though it was successfully separated from the treated solutions. Furthermore, both biochars before and after adsorption were analyzed by SEM-EDS, XRD and FTIR. Adsorption mechanisms mainly included precipitation, ion-exchange, complexation and Cπ-coordination, in which precipitation and ion-exchange dominated the adsorption process by CMB, while in M-CMB, precipitation was always predominant mechanism, followed by ion-exchange. The two other mechanisms of complexation and Cπ-coordination were trivial in both biochars, jointly contributing 7.21% for CMB and 5.05% for M-CMB to total adsorption. The findings deepen our understanding of the mechanisms governing the adsorption process, which are also important for future practical applications in the removal of heavy metals from wastewater by the biochars.
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Asaduzzaman, Abu Md, Slimane Laref, P. A. Deymier, Keith Runge, H. P. Cheng, Krishna Muralidharan, and M. J. Drake. "A first-principles characterization of water adsorption on forsterite grains." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 1994 (July 13, 2013): 20110582. http://dx.doi.org/10.1098/rsta.2011.0582.
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Numerical simulations examining chemical interactions of water molecules with forsterite grains have demonstrated the efficacy of nebular gas adsorption as a viable mechanism for water delivery to the terrestrial planets. Nevertheless, a comprehensive picture detailing the water-adsorption mechanisms on forsterite is not yet available. Towards this end, using accurate first-principles density functional theory, we examine the adsorption mechanisms of water on the (001), (100), (010) and (110) surfaces of forsterite. While dissociative adsorption is found to be the most energetically favourable process, two stable associative adsorption configurations are also identified. In dual-site adsorption, the water molecule interacts strongly with surface magnesium and oxygen atoms, whereas single-site adsorption occurs only through the interaction with a surface Mg atom. This results in dual-site adsorption being more stable than single-site adsorption.
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Tang, Yu Bin, Fang Yu, Fang Yan Chen, and Cheng Chen. "Research on Adsorption of Pb2+ on to Microspheres Prepared by Rectorite and Humic Acid." Advanced Materials Research 233-235 (May 2011): 1972–80. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1972.
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Rectorite (REC), humic acid (HA) and polyvinyl alcohol (PVA) were used to prepare microspheres. Batch adsorption experiments of Pb2+ion on to the microspheres were performed. The results obtained indicate that adsorption time, the microspheres dosage and temperature were the main factors influencing the adsorptive capacities. The adsorption data for Pb2+ion were well described by the Freundlich, Langmuir and Temkin models. The kinetic experimental data properly correlated with the pseudo-first-order model, pseudo-second-order model and Elovich equation. The adsorption process is spontaneous, endothermic and out-of-order. The whole adsorption process is mainly controlled by entropies. The adsorption can be classified as chemical adsorption. The mechanisms for the adsorption of Pb2+ion on to the microspheres involved ion-exchange adsorption of Pb2+or the formation of complex compound. Under the experimental conditions employed, the removal of Pb2+ion attained value of 96.05%.
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Strawn, Daniel G. "Sorption Mechanisms of Chemicals in Soils." Soil Systems 5, no. 1 (February 24, 2021): 13. http://dx.doi.org/10.3390/soilsystems5010013.
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Sorption of chemicals onto soil particle surfaces is an important process controlling their availability for uptake by organisms and loss from soils to ground and surface waters. The mechanisms of chemical sorption are inner- and outer-sphere adsorption and precipitation onto mineral surfaces. Factors that determine the sorption behavior are properties of soil mineral and organic matter surfaces and properties of the sorbing chemicals (including valence, electron configuration, and hydrophobicity). Because soils are complex heterogeneous mixtures, measuring sorption mechanisms is challenging; however, advancements analytical methods have made direct determination of sorption mechanisms possible. In this review, historical and modern research that supports the mechanistic understanding of sorption mechanisms in soils is discussed. Sorption mechanisms covered include cation exchange, outer-sphere adsorption, inner-sphere adsorption, surface precipitation, and ternary adsorption complexes.
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Ketratanakul, A., S. Ohgaki, and K. Yano. "Comparative Study on Adsorption Mechanisms of RNA-F-Specific Coliphages and Poliovirus in Activated Sludge Process." Water Science and Technology 24, no. 2 (July 1, 1991): 407–12. http://dx.doi.org/10.2166/wst.1991.0100.
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The adsorption mechanism of RNA-F-specific coliphages, Qβ, and poliovirus 1 in the activated sludge process was studied experimentally. The mechanisms of Qβ and poliovirus associated with microbial flocs were attributable to the pH change in the system which was caused by either microbial activity during glucose uptake or the added acids/alkalis. The adsorption mechanisms of them seemed to be similar, and the only difference was the pI level of each other. In addition, Qβwas found to be more tolerant of environmental stress than was the case for poliovirus because of Qβ being stable for a week in a batch activated sludge reactor. By contrast, poliovirus was reduced about 0.8 log in three days in the identical reactor.
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Munkhbat, Dolgormaa, Tamiraa Ganbold, Ariunzul Naranbaatar, Koichiro Shiomori, and Ochirkhuyag Bayanjargal. "Pb(II) Adsorption of Composite Alginate Beads Containing Mesoporous Natural Zeolite." Journal of Nanoscience and Nanotechnology 20, no. 8 (August 1, 2020): 5267–75. http://dx.doi.org/10.1166/jnn.2020.18530.
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Natural zeolite beads were prepared by encapsulating mesoporous zeolite into alginate beads via egg box method and its adsorption properties of Pb(II) ions were investigated in aqueous solution. Crystallinity and size reduction of natural zeolite were enhanced by mechanic modification of the ball milling process. FTIR and SEM-EDS analyses confirmed that mechanically modified zeolite particles were incorporated into alginate hydrogel. The highest adsorption amount of zeolite alginate beads was 87.47 mg/g after 20 h adsorption process. SEM-EDS result confirmed that the adsorption process has occurred on the surface of zeolite alginate beads. Adsorption kinetic data were fitted with Langmuir adsorption isotherm which showed that Pb2+ cation adsorbed into monolayers of adsorbent material. Moreover, we observed that calcium ion released after the Pb2+ adsorption process in the feed solution. Therefore, the adsorption mechanism of zeolite alginate beads explained by complex mechanisms including surface sorption and ion exchange of Pb2+ and Ca2+ in beads.
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Jia, Miao, Ji Wei Hu, Jin Luo, Su Ming Duan, Zhi Bin Li, and Chun Liu. "Comparison Study on Adsorption and Removal of Antimony from Acidic Aqueous Solution by Activated Carbons and Machine-Made Charcoal." Advanced Materials Research 779-780 (September 2013): 1600–1606. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1600.
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Adsorption effects of three kinds of activated carbons and a type of machine-made charcoal on the removal of antimony from acidic aqueous solution were investigated and compared. With an initial antimony solution concentration of 1000 μgL-1, the antimony adsorption by selected adsorbents were found to descend in the following order: machine-made charcoal (52.4%) > coconut activated carbon (42.6%) > coal based activated carbon (31.1%) > apricot stone based activated carbon (24.6%). The machine-made charcoal has the best adsorption capacity with a maximum adsorption values of 523.76 μgL-1. Five kinetic models were used for the fitting of the process of antimony adsorption, including Elovich, parabola diffusion, second order, first order and double-constant. Results showed that parabola diffusion and double-constant rate equation were the most suitable models in describing the relationship of antimony adsorption with time in acidic aqueous solution, implying that the adsorption kinetics of the antimony by the selected adsorbents in water might be a surface diffusion. Three adsorptive capacity indicators (iodine number, methylene blue number and phenol number) were determined in this paper. However, machine-made charcoal, which has a relatively high adsorption capacity, is of the lowest levels of the adsorptive capacity indicators. Thus, some complex mechanisms might be involved for the antimony adsorption by the machine-made charcoal, consequently considering the mechanism for the adsorption of antimony by the charcoal has not been verified, a further study still needs to be done.
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Mohanty, Saismrutiranjan, and Sanjoy Kumar Maji. "Adsorption/photodegradation of methylene blue from synthetic wastewater on titanate nanotubes surfaces." Water Science and Technology 82, no. 11 (November 5, 2020): 2562–75. http://dx.doi.org/10.2166/wst.2020.535.
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Abstract Titanate nanotubes (TNTs) were hydrothermally synthesized from commercially available TiO2 powder and were characterized by XRD, SEM/EDX, and TEM. The as-prepared TNTs were used to remove organic dye, Methylene Blue (MB) from aqueous media by batch mode at 25 ± 2 °C, at pH 6.8 ± 0.2. The MB removal process followed two mechanisms of adsorption (absence of UV light) and photodegradation on precursor's surfaces. Photo-illumination study revealed the ∼98% MB removal with the dose of 3 g/L TNT with an initial concentration of 10 mg/L. Adsorptive capacity of TNT was evaluated from the Langmuir isotherm and found to be 151.51 mg/g. Dimensionless equilibrium parameter RL value suggested the favourable but the free energy changes (ΔG°) value (10.752 kJ/mol) suggested the non-spontaneity of the adsorption process. Adsorption followed the pseudo-second order kinetics model best. MB adsorption onto TNT surfaces followed neither pore diffusion nor film diffusion. Studies conducted in the presence of different foreign ions as well as varying pH of the media to understand their effects in the process if any. Turnover studies were also conducted. A probable photodegradation mechanism was proposed. Finally, TNT was used to remove MB from spiked pond water collecting from the KISS University, including pre- and post analysis of water quality.
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Xu, Nan, Hong Wei Yin, Zhi Gang Chen, Ming Chen, and Shou Qing Liu. "Mechanisms of Phosphate Removal by Synthesized Calcite." Materials Science Forum 743-744 (January 2013): 597–602. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.597.
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Calcite was synthesized through different drying processes, and characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). By bath experiments, the mechanisms of phosphate removal by synthesizing calcite were investigated. It showed that synthesis calcite had a strong capability to remove phosphate from solution. The adsorption of phosphate mainly depended on the total concentration of phosphate and pH in solution. Magnesium tended to the phosphate adsorption during pH range of 8-13.5; while it inhibited the adsorption at around pH 7. The experimental results suggested that the synthesized calcite with aged process could effectively remove the phosphate from an alkaline aqueous solution.
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Pinisakul, A., C. Polprasert, P. Parkpian, and J. Satayavivad. "Arsenic removal efficiency and mechanisms by electro-chemical precipitation process." Water Science and Technology 46, no. 9 (November 1, 2002): 247–54. http://dx.doi.org/10.2166/wst.2002.0250.
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This research was conducted to investigate the efficiency and mechanisms of arsenic (As) removal from a contaminated water by using the electro-chemical precipitation (ECP) process, with the operating conditions as follows: initial As concentration of 0.5-5 mg/L, 0.1 M KCl, electrical gradient of 200 V/m and initial pH higher than 3. The laboratory-scale ECP unit was able to reduce As to within the WHO drinking water standard of 0.01 mg/L in 20 min. The ClÐ salt was found to yield better As removal efficiencies than the NO3− salt probably because NO3− ions interfered with the production of OH− and Fe(OH)3, important for As removal. X-ray fluorescence and X-ray diffractometric analysis revealed maghemite (Fe2O3) and angelellite (Fe4As2O11) to be the major compounds present in the precipitated sludge. The percent Fe2O3 and Fe4As2O11 contents of the dried ECP sludge were 98.29% and 0.26%, respectively. From a mass balance analysis, As removal in the ECP process was due to: incorporation in and adsorption on the ECP sludge - 64.9-94.9%, conversion to arsine (AsH3) gas - 10.5-15.6%, adsorption on the electrode plates and reactor walls - 0.03-1.1%, residual in the supernatant - 0.2-0.4%, and unaccounted for - 1.2-19.8%.
Dissertations / Theses on the topic "Process adsorption mechanisms"
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Frazier, Jeffrey A. "Evaluation of the physico-chemical mechanisms by which residual cooking liquor retards kraft delignification." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/7029.
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Ren, Baiming. "Transforming alum sludge into value-added products for various reuse." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2019. http://www.theses.fr/2019EMAC0002.
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La forte augmentation de la population mondiale entraîne une demande croissante en eau potable. La production d'eau potable est accompagnée par la génération de résidus du traitement de l'eau dont la boue d'aluminium qui est donc largement disponible mondialement. Ce travail se concentre sur l'identification des différentes voies de valorisation des boues d'aluminium afin de les réutiliser dans le domaine de l’environnement. Deux sources de boues d'aluminium, collectées en France et en Irlande, ont été étudiées dans divers domaines d’application en fonction de leurs caractéristiques. Tout d'abord, les boues d'aluminium ont été utilisées en remplacement d’une partie de l'argile dans la fabrication des briques, en incorporant différents pourcentages de boues d'aluminium et à différentes températures. Les briques résultantes ont été caractérisées et les résultats ont montré que les briques composées de boues d'aluminium et d'argile sont conformes aux « normes européennes et irlandaises » et démontrent ainsi le potentiel pour une application industrielle des boues d'aluminium dans la fabrication de briques en terre cuite irlandaises. Dans un second temps, les boues d’aluminium ont été utilisées comme adsorbant des polluants présents dans l’agriculture. Le glyphosate est un ingrédient actif dans les pesticides utilisés massivement dans l'agriculture irlandaise et représente une problématique environnementale. La boue d’aluminium et la tourbe irlandaise ont été comparées pour l’élimination du glyphosate lors de tests en pot à l’échelle laboratoire. Les résultats ont montré que la boue d’aluminium permet d’éliminer le glyphosate à plus de 99% et réduire les niveaux de DCO. Cet aspect scientifique a permis d’être dans la sélection des adsorbants possibles pour le traitement des eaux usées agricoles en Irlande. Le co-conditionnement et la déshydratation des boues de station d’épuration avec des boues d’aluminium liquides ont également été étudiés. Pour cela, le Jar test a été effectué sur des boues issues d’une station de traitement des eaux française. Les résultats ont montré que le rapport optimal de mélange des boues est de 1:1 (boues d’épuration : boues d’aluminium). Ainsi, la quantité de polymère utilisée peut être diminuée de 14 fois par rapport aux technologies actuelles. Cette approche a permis de montrer la possible valorisation des boues d’aluminium comme un moyen durable et technique permettant ainsi l’élimination des boues localement pour une même station de traitement des eaux. Une autre voie de valorisation des boues d’aluminium comme adsorbant pour la purification des gaz a été étudiée lors d’expériences d’adsorption de H2S dans un réacteur à lit fixe dans différentes conditions expérimentales. Les données expérimentales d’adsorption du H2S ont été modélisées à l'aide de modèles empiriques basés sur la cinétique des processus d'adsorption. Les résultats ont montré que les boues d'aluminium sont un adsorbant efficace pour l'élimination du H2S (capacité de 374,2 mg H2S / g solide) et que des mécanismes mis en jeu sont l'adsorption dissociative et l'oxydation. Les coefficients de transfert de masse globaux ont également été calculés et pouvant ainsi être utilisés pour la prédiction. Enfin, les gâteaux de boues d'aluminium ont été réutilisés pour la purification simultanée d’H2S et le traitement des eaux usées. Les résultats ont montré la capacité de cet adsorbant pour éliminer tout le H2S présent avec une grande efficacité d’élimination de la DCO, TN et TP. Ainsi, il a été démontré la valorisation des boues d’aluminium en tant qu’adsorbant pour une purification du H2S simultanée avec le traitement des eaux uséesThe production of drinking water always accompanied by the generation of water treatment residues (WTRs). Alum sludge is one of the WTRs, it is an easily, locally and largely available by-product worldwide. This work focuses on the identification of different ways to valorize the alum sludge for environmentally friendly reuse. Two alum sludges collected from France and Ireland have been reused in various fields as a function of their characteristics. Firstly, alum sludge was used as a partial replacement for clay in brick making, by incorporating different percentages of alum sludge and calcined at different temperatures (range from 800 to 1200 °C). The resultant bricks were tested for compression, Loss on Ignition, water absorption, appearance, etc. Results show that alum sludge-clay bricks have met the “European and Irish Standards” and demonstrated the huge industrial application potential for alum sludge in Irish clay brick manufacturing. Glyphosate is an active ingredient in pesticide which is massive employed in agriculture. Alum sludge and Irish peat were compared for glyphosate removal in pot tests, results show that alum sludge present significant glyphosate removal capacity (>99 %) and could reduce the level of Chemical Oxygen Demand (COD). It provided a scientific clue for sorbents selection when considering the agricultural wastewater treatment in Ireland and to maximize their value in practice. The co-conditioning and dewatering of sewerage sludge with liquid alum sludge was also investigated in Jar-test based on the case analysis of a water industry in France. Results show that the optimal sludge mix ratio is 1:1, the use of the alum sludge has been shown to beneficially enhance the dewaterability of the resultant mixed sludge, and highlighting a huge polymer saving (14 times less than the current technologies) and provided a sustainable and technical sludge disposal route for the local water industry. The use of alum sludge as a sorbent for gas purification was studied by H2S adsorption experiments in a fixed-bed reactor with various operating parameters. The experimental breakthrough data were modeled with empirical models based on adsorption kinetics. Results show that alum sludge is an efficient sorbent for H2S removal (capacity of 374.2 mg/g) and the mechanisms including dissociative adsorption and oxidation were proposed. Moreover, the overall mass transfer coefficients were calculated which could be used for the process scaling up. Finally, alum sludge cakes were reused in the novel aerated alum sludge constructed wetland (CW), which were designed for simultaneous H2S purification and wastewater treatment. Results show that H2S was completely removed in the six months’ trials, while the high removal efficiencies of COD, total nitrogen (TN), total phosphates (TP) were achieved. Thus, a novel eco-friendly CW for simultaneous H2S purification and wastewater treatment was developed. In the different approaches and process considered, in particular it was put in investigating and describing the mechanisms involved. Overall, this work demonstrated alum sludge could be a promising by- product for various novel beneficial reuse rather than landfilling and provided a “Circular Economy” approach for WTRs management
Books on the topic "Process adsorption mechanisms"
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Ryabov, Vladimir. Oil and Gas Chemistry. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1017513.
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The textbook provides up-to-date data on the composition and properties of hydrocarbons and other oil and gas compounds, on the physical and chemical methods and methods for separating and identifying oil components (molecular spectroscopy, mass spectrometry, NMR spectroscopy, electron paramagnetic resonance, atomic adsorption spectroscopy, neutron activation analysis). The chemistry and mechanism of thermal and catalytic transformations of oil components in the main processes of oil raw materials processing, as well as the problems of the origin of oil and the transformation of oil in the environment are considered.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
It is intended for training in the course "Chemistry of oil and gas", for the preparation of bachelors, masters and certified specialists in the field of training "Oil and Gas business". It can be used for training in other areas in oil and gas universities and be of interest to specialists working in the field of chemistry and technology of oil refining and in other areas of the oil and gas industry.
Book chapters on the topic "Process adsorption mechanisms"
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Argyropoulos, Vasilike, Stamatis C. Boyatzis, Maria Giannoulaki, Elodie Guilminot, and Aggeliki Zacharopoulou. "Organic Green Corrosion Inhibitors Derived from Natural and/or Biological Sources for Conservation of Metals Cultural Heritage." In Microorganisms in the Deterioration and Preservation of Cultural Heritage, 341–67. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69411-1_15.
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AbstractIn the last decade, there has been an increase in research related to green corrosion inhibitors for conservation of metals cultural heritage to help promote sustainable practices in the field that are safe, environmentally friendly, and ecologically acceptable. The most common are organic substances derived either from natural and/or biological sources: plant extracts and oils, amino acids, microorganisms, and biopolymers. The chapter will provide a review of these substances as corrosion inhibitors for metals conservation, by discussing the state-of-the-art research to date, with a special focus on cysteine. Most of the research has focused on the examination of such inhibitors on metal coupons with or without corrosion products using electrochemical techniques or weight-loss measurements to determine their effectiveness. Some of these studies have also considered the conservation principles for practice, i.e., reversibility of the treatment and the visual aspect of the modification of the treated metal surface. However, before such green inhibitors can be routinely applied by conservators, more research is required on their application to real artefacts/monuments using in situ corrosion measurements. Furthermore, given that the composition of a green inhibitor is highly dependent on its extraction process, research must also involve identifying the specific adsorption models and involved mechanisms to ensure reproducibility of results.
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Boyd, Stephen A., Cliff T. Johnston, David A. Laird, Brian J. Teppen, and Hui Li. "Comprehensive Study of Organic Contaminant Adsorption by Clays: Methodologies, Mechanisms, and Environmental Implications." In Biophysico-Chemical Processes of Anthropogenic Organic Compounds in Environmental Systems, 51–71. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470944479.ch2.
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Gusain, Deepak, Shikha Dubey, Yogesh Chandra Sharma, and Faizal Bux. "Impact of Initial Concentration, Adsorbent Dose, and Ionic Strength on Batch Adsorption of Metals and Anions and Elucidation of the Mechanism." In Batch Adsorption Process of Metals and Anions for Remediation of Contaminated Water, 239–48. First edition. | Boca Raton : CRC Press, 2021.: CRC Press, 2021. http://dx.doi.org/10.1201/9781003006367-7.
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Gusain, Deepak, Shikha Dubey, Yogesh Chandra Sharma, and Faizal Bux. "Remediation of Essential Elements Exerting Toxicity on Excessive Exposure (Mn, Co, Cu, Zn, Se) Via Batch Adsorption in Response to Variable Factors and Elucidation of the Mechanism for the Batch Adsorption Process." In Batch Adsorption Process of Metals and Anions for Remediation of Contaminated Water, 133–82. First edition. | Boca Raton : CRC Press, 2021.: CRC Press, 2021. http://dx.doi.org/10.1201/9781003006367-4.
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Ge, Hui, Mingxing Tang, and Xiao-Dong Wen. "Ni/ZnO Nano Sorbent for Reactive Adsorption Desulfurization of Refinery Oil Streams." In Applying Nanotechnology to the Desulfurization Process in Petroleum Engineering, 216–39. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9545-0.ch007.
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The aim of this chapter is to present the Ni/ZnO nano-sorbent for reactive adsorption desulfurization (RADS) of refinery oil steams. The preparation and modification of nano-sorbent are reviewed. Various characterizations involving in the relation of properties with components, structures and dynamic phase change during RADS, are extensively provided. The mechanisms of desulfurization, sulfur transfer and sulfur adsorption are proposed. The contradictories in literature about active structures and reaction mechanism are discussed and the solutions are suggested. This chapter unfolds the impressive application of RADS of Ni/ZnO nano-sorbent to produce a cleaner gasoline. It also delves into the inadequately engineer areas which require further attention so as to make the RADS process more economic and more efficient. The perspective applications other than gasoline desulfurization are also presented.
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Taofeek Popoola, Lekan, and Alhaji Shehu Grema. "Adsorption of Heavy Metals from Industrial Wastewater using Nanoparticles from Agro Wastes." In Nanopores [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98241.
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Effluents from essential industries have been characterized with heavy metals which are non-biodegradable in nature and also detrimental to health when accumulated in body tissues over long exposure. Adsorption was proved as the best efficient process amongst others to remove these heavy metals from industrial wastewater due to its excellent features. Activated carbons from nanoparticles of agricultural wastes such as pods, shells, husks, peels, shafts and many prepared via calcination process at high temperature can be used as active adsorbent for the industrial wastewater treatment involving heavy metals removal. This chapter discusses heavy metals in industrial wastewater effluents and potential agro wastes from which nanoparticles of activated carbon for industrial wastewater purification could be generated. The transformation of agro wastes nanoparticles into activated carbons via calcination and their applications for heavy metals removal from industrial wastewater via adsorption were examined. Various characterization techniques to study the effects of calcination on structural, morphological and textural properties of activated carbon prepared from agro waste nanoparticles were also discussed. Various isotherm, kinetics, mechanistic and thermodynamics models to investigate the adsorptive nature of the process were presented. Error functions and algorithms for both the linear and non-linear isotherm models regression to affirm their fitness for prediction were presented. Lastly, proposed adsorption mechanisms of heavy metals removal from industrial wastewater using activated carbons from nanoparticles of agro wastes were presented.
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"State-of-the-Art Materials for Adsorptive Heat Energy Conversion." In Technology Development for Adsorptive Heat Energy Converters, 1–24. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4432-7.ch001.
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The chapter is focused on state of the art of materials for adsorptive heat energy conversion basic principles for substantiation of working pair choice. Types of heat storage materials based on heat storage mechanism were compared. Sensible heat mechanism of thermal energy is based on increasing the temperature of the material. Phase-change mechanism of heat energy storage concerns with alternating reversible processes of phase-changing. As a rule, they are mainly melting-crystallization. Thermo-chemical heat energy storage mechanism is based on reversible chemical reactions. Limitations of conventional sensible heat storage are shown to lowest density of heat energy storage determined by sensible heat of materials, which led to large mass storage units and additional needs of large areas and building volumes, calculated according to heat storage density, constant changing the temperature when discharged, the need for a large overheating of heat storage media. The main defects of phase-change materials are instability of properties of heat-accumulating substances in multiple cycles of crystallization – melting, degradation in time, corrosion activity, the need for developed surfaces of heat exchange and environmental danger. Commercilisation of thermal chemical storage materials is strongly limited by high operating temperatures of thermal chemical storage materials, which are unacceptable for systems of district heating and decentralized heat supply due to sanitary regulations, impropriety for multifold cycling because of irreversibility of a wide range of chemical reactions. Perspective of adsorptive heat energy storage and conversion is shown. Interval of operating temperatures and heat storage density of conventional adsorptive materials are shown to be intermediate between phase-change and thermal chemical heat storage materials. Properties of probable adsorptive heat storage materials were analysed according with literary data. Low adsorptive capacity of conventional adsorbents results in low heat of adsorption and heat energy storage density. Salts forming crystalline hydrate occur to exhibit rather high energy storage density of 1.9–2.7 GJ/m3 of crystalline hydrate, but their application is strongly inhibited not only by physical and chemical instability along with the corrosive activity of these salts at high temperatures, but instability in multifold cycling, degradation in time, and an underdeveloped heat exchange surface. As engineering solution, modification of conventional adsorbents with salt can be considered. Composites ‘salt inside porous matrix' is shown to be promising alternative to conventional adsorbents. Main advantages of these materials are low regeneration temperature and high adsorptive capacity. Crucial impediments of industrial introduction of composite adsorbents ‘salt inside porous matrix' is shown to be complex technology of their production based on rather expensive dry and wet impregnation of porous media by crystalline hydrate solutions. As an alternative, sol gel method for obtaining composite adsorbents ‘silica gel – crystalline hydrate' developed by authors is suggested. The adsorption properties of the obtained composite adsorbents ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' are shown to be non-linear combinations of characteristics of silica gel and massive salt. The key distinction of kinetics of adsorption of water vapor with massive salts and composites obtained with sol gel method is shown to be difference limitative stage of process. The adsorption of water with massive crystalline hydrates is shown to be complicated by kinetic limitations. For composite adsorbents limiting stage is water transport through the pore system. Composites ‘slilica gel – crystalline hydrate' are shown to be a promising material for adsorptive heat energy storage and conversion.
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Alaoui, Khaoula, Ashraf Abousalem, Burak Tüzün, and Younes El Kacimi. "Triazepines Compounds as Novel Synthesized Corrosion Inhibitors." In New Challenges and Industrial Applications for Corrosion Prevention and Control, 156–86. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2775-7.ch007.
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This chapter describes some recent good works in the field of metallic corrosion monitoring using Triazepine carboxylate inhibitors in hydrochloric acidic media. The different sections of this chapter cover electrochemical measurements and theoretical investigations. This review reveals Triazepine carboxylate compounds as very good inhibitors for mild steel in hydrochloric medium. The inhibition action of all Triazepine carboxylates compound studied was performed via adsorption on mild steel surface. Comparison between several adsorption isotherms reveal that the adsorption was spontaneous and followed Langmuir isotherm in HCl for all inhibitors and all studied temperatures. Kinetic and thermodynamic parameters for all inhibitors led to suggest the occurrence of chemical mechanism and also the spontaneity of the adsorption process on mild steel surface. The corrosion inhibition mechanism was also compared and discussed with the light of some Triazepine carboxyale compounds constituents.
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Saleh, Tawfik A. "Advanced Desulfurization Technologies and Mechanisms." In Nanocomposites for the Desulfurization of Fuels, 1–24. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2146-5.ch001.
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This chapter describes different desulfurization technologies used for the removal of sulfur from petroleum products or from refined products. These technologies include hydrodesulfurization and non-hydrodesulphurization such as extractive desulphurization, adsorptive desulfurization, precipitative desulphurization, oxidative desulphurization, and desulfurization by membranes. Types of reactors including batch and fixed bed reactors are discussed. The chapter also highlights some of the common mechanism to explain the desulphurization process.
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Nyairo, Wilfrida Nyanduko, Emily Ng'eno, Victor Odhiambo Shikuku, and Patrick Ssebugere. "Application of Metal-Organic Framework Adsorbents for Water Defluoridation." In Emerging Applications and Implementations of Metal-Organic Frameworks, 74–91. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4760-1.ch005.
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Defluoridation of drinking water is a subject of great concern due to the side effects of exposure to fluorine such as fluorosis, damage to vital organs such as the brain, liver, and kidney, among others. Fluorine finds itself in water resources both by geological and anthropogenic processes. Adsorption still remains the popular method of defluoridation and water treatment in general due to its inherent advantages such as simplicity and low-cost. This chapter discusses at length the up-to-date data on the preparation and adsorption capacities of metal-organic framework (MOF) materials as emerging adsorbents for sequestration of fluoride from water. Their synthesis, efficiency, and suggested adsorption mechanisms are examined. It is demonstrated that MOFs are low-cost, efficient, and environmentally benign alternative adsorbents for the removal of fluoride from aqueous solution.
Conference papers on the topic "Process adsorption mechanisms"
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Yu, Huili, Kaili Zhang, and Carole Rossi. "Theoretical Investigation on Nano TiO2 Photocatalytic Oxidation of VOCs." In 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21406.
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Controlling mechanisms for photocatalytic degradation of volatile organic compounds by nano TiO2 catalyst are found to be mass transfer, diffusion, adsorption and photochemistry. A mathematical model for the degradation process is developed by incorporating these mechanisms in a plane plate air purification physical model. Finite difference method is employed to solve the governing equation and boundary conditions. The computation results are validated using the data from experiments. The model is then used to investigate the effects of some key factors on the degradation of formaldehyde including UV light intensity, UV light attenuation coefficient, adsorption, catalyst thickness, and flow rate.
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Seniūnaitė, Jurgita, Rasa Vaiškūnaitė, and Kristina Bazienė. "Mathematical Modelling for Copper and Lead Adsorption on Coffee Grounds." In Environmental Engineering. VGTU Technika, 2017. http://dx.doi.org/10.3846/enviro.2017.007.
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Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.
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Adegoke, Samuel Oluwafikayo, Olugbenga Adebanjo Falode, and Princess Christiana Nwankwo. "Understanding Oilfield Scale Deposition and Inhibition Mechanisms for Optimum Management: A Review." In SPE Nigeria Annual International Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/207133-ms.
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Abstract Oilfield scales are crystalline minerals made up of Na, K, Mg, Ca, Ba, Sr, Fe, Cl from produced water that can precipitate out in the reservoir, well, pipelines and process during the production and transportation of oil and gas. These precipitates can deposit as a result of thermodynamic and/or chemical changes and pose costly flow assurance issues to the oil industry. Several factors have been identified to be responsible including temperature, pressure, ionic strength, pH, evaporation, bicarbonate anion, super-saturation and contact time and water chemistry. Attempts to solve this problem in the past have focused mainly on the use of chemical inhibitors and the most accepted mechanism of scale inhibition is squeeze injection method. While adsorption and retention of scale inhibitors on rock formations needs more research, there had been improvement to better ways of ensuring adsorption and precipitation through nanotechnology including the use of nano-carbon enhanced squeeze treatment (NCEST). The uses of these conventional inhibitors have been found to be toxic to the flora and fauna in biotic communities during water disposal. In order to reduce the environmental burden caused by these conventional solutions and still manage the problem effectively, greener solutions have been proposed. This review x-rays the mechanisms of scale precipitation and deposition, evaluate the solutions that have been provided in literature based on efficiency, economics and environmental impact and propose guidelines to field operators in selecting optimum solutions.
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Uddin, Ghulam Moeen, Bing Sun, Katherine Ziemer, Abe Zeid, and Sagar Kamarthi. "Monte Carlo Study of the Molecular Beam Epitaxy Process for Manufacturing Iron Oxide Nano Scale Films and Similarities With Magnesium Oxide Films." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65570.
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Functional properties of thin film metal oxides depend upon their stoichiometric and structural uniformity. Controlling the film deposition process can help tune the functionality of these films by ensuring the control over chemistry and structure of the films. The high volume manufacturing of functional devices will benefit from the development of reliable control models developed from research efforts in designing robust manufacturing processes. The use of neural networks as computer models to simulate the molecular beam epitaxy (MBE) of iron oxide thin films is presented in this work. Monte Carlo experiments are used to study the sensitivities and significances of process control variables to the stoichiometric performance indicators. Moreover, we also explore the relationship between growth dynamics of iron oxide (Fe2O3, Fe3O4, and mixed FexOy) and magnesium oxide (MgO) thin films. The common metal adsorption controlled growth mechanism of two films with different structural and stoichiometric complexities were observed and the similarities among the trends of analogous stoichiometric indicators at comparable metal arrival rates of the two films are presented. The dependence of undesirable bonding states of iron and magnesium metals with the film thicknesses was also observed in both processes. The commonalities suggest the potential to use of neural network assisted Monte Carlo analysis to link common atomic-level mechanisms to processing variables in one nano-scale system and use them to predict some level of behavior in other nanoscale processes with similar atomic-level mechanisms.
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Sousa, Gustavo Gomes de, and José Roberto dos Santos Politi. "ASPECTOS ENERGÉTICOS E ELETRÔNICOS DA ZEÓLITA H-ZSM-5 NA AÇÃO CATALÍTICA DA REAÇÃO DE DESIDRATAÇÃO DE ÁLCOOIS." In VIII Simpósio de Estrutura Eletrônica e Dinâmica Molecular. Universidade de Brasília, 2020. http://dx.doi.org/10.21826/viiiseedmol202087.
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Due to the growth of ecological concerns and the need to reduce dependence on fossil fuels, the dehydration of alcohols by acid catalysis has been used for the production of various hydrocarbons. Inside this theme, the H-ZSM-5 zeolite has been widely used as a catalyst for this reaction because its high efficiency. Thus, in order to understand the catalyzed reaction mechanism of the alcohol dehydration reaction, this work used the computational methodology ONIOM to study the catalytic behavior of the H-ZSM-5. It was modeled the dehydration reaction process for several alcohols (ethanol, propanol, isopropanol, butanol and 2-butanol) by modeling these alcohols within the zeolite cavity. The study was divided into 3 stages: the adsorption and protonation of alcohols by zeolite, the description of the hydroxyl outlet, and the formation of the double bond. The analysis of the results indicates that the first stage of the reaction occurs with the contact of alcohol with the zeolite cavity, where acid hydrogen promotes the protonation of alcohols, occurring differently for each alcohol. The dehydration process occurs, preferably, via E2 type elimination mechanisms. However, the profile of the energy curves indicates that for larger alcohols, the mechanism is intermediate between the elimination mechanisms E2 with some features of E1 (E2[E1]). Therefore, the zeolite converts alcohols to hydrocarbons in a specific way. Primary, lower-chain alcohols follow E2 mechanism, while secondary and longer-chain alcohols react by a slightly different mechanism, namely E2[E1].
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Jang, Changsoo, and Seungbae Park. "On Water Behavior Inside and Around a Void at Polymer Interface." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-16255.
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As the use of polymeric materials is increasing in microelectronics industry, the failure issues related to moisture are getting more popular. Moisture absorbed into the electronic package causes interfacial delamination through the synergetic effects of hygro-thermo-mechanical stresses and degradation of adhesion strength. It also results in catastrophic crack propagation during reflow process, called pop-coming. Vapor pressure inside preexisting voids at material interfaces is known to be a dominant driving force of this phenomenon. In order to explain vapor pressure generation at high reflow temperature, researchers so far have been presuming two mechanisms: liquid water boiling and quick moisture diffusion. In spite of the importance as a basis of the failure analysis, there has been little focus on the mechanism of liquid water accumulation, more exactly, high vapor pressure generation inside voids. In this study various known mechanisms of liquid water formation inside a void at polymer interface are reviewed. They include condensation, adsorption, capillary, and microfogging. As an alternative possibility, moisture diffusion around the void for a short reflow period is also assessed through numerical analysis.
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Li, Shidong, and Ole Torsæter. "The Impact of Nanoparticles Adsorption and Transport on Wettability Alteration of Intermediate Wet Berea Sandstone." In SPE Middle East Unconventional Resources Conference and Exhibition. SPE, 2015. http://dx.doi.org/10.2118/spe-172943-ms.
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AbstractNanoparticles as part of nanotechnology have drawn the attention for its great potential of increasing oil recovery. From authors' previous studies (Li et al., 2013a), wettability alteration was proposed as one of the main Enhanced Oil Recovery (EOR) mechanisms for nanoparticles fluid, as adsorption of nanoparticles on pore walls leads to wettability alteration of reservoir. We conducted a series of wettability measurement experiments for aged intermediate-wet Berea sandstone, where the core plugs were treated by different concentration and type of nanoparticles fluid. Nanoparticles transport experiments also were performed for core plugs with injection of varying concentration and type of nanoparticles fluid. Pressure drop across the core plug during injection was recorded to evaluate nanoparticles adsorption and retention inside core, as well as desorption during brine postflush. Both hydrophilic silica nano-structure particles and hydrophilic silica colloidal nanoparticles were utilized in above two experiments.The results of wettability alteration experiments indicated that hydrophilic nanoparticles have ability of making intermediate-wet Berea sandstone to be more water wet, and basically the higher concentration the more water wet will be. And different type of nanoparticles has different effect on the wettability alteration process. For nanoparticles transport experiments, the results showed that the nanoparticles undergo both adsorption and desorption as well as retention during injection. Pressure drop curves showed that absorption and retention of nano-structure particles inside core was significant while colloidal nanoparticles did not adsorb much. Permeability impairment was observed during nano-structure particles fluid injection, but on the contrary colloidal nanoparticles dispersion injection made core more permeable.
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Egan, B. Z., D. E. Fain, G. E. Roettger, and D. E. White. "Separating Hydrogen From Coal Gasification Gases With Alumina Membranes." In ASME 1991 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/91-gt-132.
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Synthesis gas produced in coal gasification processes contains hydrogen, along with carbon monoxide, carbon dioxide, hydrogen sulfide, water, nitrogen, and other gases, depending on the particular gasification process. Development of membrane technology to separate the hydrogen from the raw gas at the high operating temperatures and pressures near exit gas conditions would improve the efficiency of the process. Tubular porous alumina membranes with mean pore radii ranging from about 9 to 22 A have been fabricated and characterized. Based on the results of hydrostatic tests, the burst strength of the membranes ranged from 800 to 1600 psig, with a mean value of about 1300 psig. These membranes were evaluated for separating hydrogen and other gases. Tests of membrane permeabilities were made with helium, nitrogen, and carbon dioxide. Measurements were made at room temperature in the pressure range of 15 to 589 psi. In general, the relative gas permeabilities correlated qualitatively with a Knudsen flow mechanism; however, other gas transport mechanisms such as surface adsorption may also be involved. Efforts are under way to fabricate membranes having still smaller pores. At smaller pore sizes, higher separation factors are expected from molecular sieving effects.
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Al Ezzi, Amged, and Hongbin Ma. "Equilibrium Adsorption Isotherm Mechanism of Water Vapor on Zeolites 3A, 4A, X, and Y." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72601.
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Many researchers have analyzed the equilibrium adsorption isotherm mechanism of water vapor molecules on 4A, 3A, Y and X zeolites for decades. The demand for moisture removal continues to increase along with the increasing stringency of requirements for product quality control and production energy efficiency. Due to the negative charge of the zeolite framework, exchangeable compensation cations such as Na+, Li+, K+, Ba2+, Mg2+, and Ca2+ might be added. These cations are located at different sites within the framework and with different concentrations. Each cation shows a strong affinity to bond with water molecules. Adsorption sites must show a characteristic energy signature corresponding to the adsorbed amount. The values of enthalpies and entropies at each site are different since the bonding strength between the moisture molecules and cations of the site is also different. These exchangeable cations have a very important contribution in determining the zeolites adsorptive properties and selectivity. This investigation of the water vapor adsorption mechanism reveals that size, location, and type of exchangeable compensation cations have a concrete relationship to the adsorption process and zeolite cage capacity.
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Yang, Xiaofan, and Z. Charlie Zheng. "Continuum/Nano-Scale Simulation of Surface Diffusion Process in Flow." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62960.
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Fluid transport with diffusion through micro-/nano-channels is found in many natural phenomena and industrial processes, including fluid transport or diffusion through nano-materials, molecular/atomistic transfer across nuclear pores or in the MEMS devices among other applications. Those nano-pores can be treated as nano-channels in the thin layers of the membranes. The transport phenomena of fluid in such small confined channels, usually in the size of ten molecular diameters or less, differs significantly from its bulk behaviors and cannot be described with continuum theory. In this case, molecular dynamics (MD) simulation, rather than continuum methods, is better suited to study the phenomena. The surface diffusion, related to both the fluid and solid material properties and the flow rate, can be used as a parameter for estimating the adsorbing capacity of a porous nano-material. The transport of fluids through porous materials occurs mainly by diffusion. In this study, a molecular-continuum hybrid scheme is used for the study of the diffusion in a representative Couette flow problem. By varying the velocity of the moving-solid wall, we investigated the effect of the shearing condition on the mass flux going through the pores. The relationship of the physical mechanisms and the transport phenomena (e.g. Fick’s law) were then linked among the different length scales. Activated carbon with its high surface area has been emerging as a promising candidate for an adsorbent due to not only its stable thermodynamic and mechanical properties but also its homogenous and isotropic porous distribution and relatively even pore size. In this study, we focus on the characteristics of the permeation and the adsorption process between different gases and the carbon substrate under various shearing conditions. The investigation of the diffusion process of fluids through the pores of the nano-materials has become an interesting topic in recent decades. This investigation has been divided into two major areas: 1) the diffusivity estimation and 2) the transient diffusion rate. We apply a continuum/MD hybrid scheme to a model problem of various gases transport through a carbon substrate with several pores in a channel flow under different shear rates. Instead of inserting and deleting particles from the control volumes used in the DCV-GCMD method, we keep the number of particles in the simulation system constant. The interactions between fluid/fluid, fluid/solid and solid/solid are all assumed to be under Lennard-Jones potentials. In the modeled Couette flow, the two solid walls are constructed with nano-pores that allow fluids to go through the substrate to study the transient diffusion rate (flux). Before simulating the fluid transport through the nano-pores, we need to validate the natural diffusion properties of the bulk fluid. To do this, a system (as a cube) consisting of pure liquid argon molecules is used to perform the pure MD simulation. The radial distribution function (RDF) is used as the parameter to verify the natural diffusion of the liquid argon fluid in the bulk flow, which is a structural correlation. It describes the spherically averaged local organization around any given molecule. Figure 1 shows a good comparison of the radial distribution functions between the MD prediction and the experimental measurement of Eisenstein and Gingrich (1942). By comparing our calculation to Wu et al. (2008) under similar circumstances, we found that the average (from 8 pores) and corrected mass flux J · (RTh) is linearly proportional to the average pressure gradient along the pore. And the slope of this relationship is the transport diffusivity, which is 4.6 × 10−7m2/s under 273K and 4.9 × 10−7m2/s under 300K. This indicates that the current simulation follows the Fick’s law exactly. Similarly, for other gases, the same linear relationships can also be obtained. These calculations are listed in Table 1 that shows the transport diffusivity increases with temperature. The mass fluxes of three gases at various pore widths are calculated as shown in Fig. 2. Generally, with larger pores, the mass fluxes increase. However, among three gases, the increase of H2 is much faster than the other two gases because of hydrogen’s smaller molecular size. In another word, smaller molecules as H2 have faster diffusion rates during the adsorption process.
Reports on the topic "Process adsorption mechanisms"
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Netus, B. Adsorption of radionuclides on minerals studies illustrating the effect of solid phase selectivity and of mechanisms controlling sorption processes. Office of Scientific and Technical Information (OSTI), February 1996. http://dx.doi.org/10.2172/184259.
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