Yes / We present here a quantification of the sorption process and molecular conformation involved in the attachment of bacterial cell wall lipopolysaccharides (LPSs), extracted from Escherichia coli, to silica (SiO2) and alumina (Al2O3) particles. We propose that interfacial forces govern the physicochemical interactions of the bacterial cell wall with minerals in the natural environment, and the molecular conformation of LPS cell wall components depends on both the local charge at the point of binding and hydrogen bonding potential. This has an effect on bacterial adaptation to the host environment through adhesion, growth, function, and ability to form biofilms. Photophysical techniques were used to investigate adsorption of fluorescently labeled LPS onto mineral surfaces as model systems for bacterial attachment. Adsorption of macromolecules in dilute solutions was studied as a function of pH and ionic strength in the presence of alumina and silica via fluorescence, potentiometric, and mass spectrometry techniques. The effect of silica and alumina particles on bacterial growth as a function of pH was also investigated using spectrophotometry. The alumina and silica particles were used to mimic active sites on the surface of clay and soil particles, which serve as a point of attachment of bacteria in natural systems. It was found that LPS had a high adsorption affinity for Al2O3 while adsorbing weakly to SiO2 surfaces. Strong adsorption was observed at low pH for both minerals and varied with both pH and mineral concentration, likely in part due to conformational rearrangement of the LPS macromolecules. Bacterial growth was also enhanced in the presence of the particles at low pH values. This demonstrates that at a molecular level, bacterial cell wall components are able to adapt their conformation, depending on the solution pH, in order to maximize attachment to substrates and guarantee community survival. / The authors thank the Libyan Ministry of Education for financial support during the experimental study. We thank the EPSRC funded consortium “Hard-soft matter interfaces: from understanding to engineering” (EP/I001514/1) for financial support. Emily Caseley, who assisted in the preparation and characterization of AmNS-LPS particles as an MRC Confidence in Concept funded postdoctoral researcher at the University of Bradford, (MC_PC_16038).

Investigations of soil parameters, infiltration testing, and storm observations are used to determine the infiltration characteristics for three Central Florida stormwater holding basins. Basic soil parameters are investigated and a value for available soil water storage is computed from these data. In-situ permeability and infiltration tests are used to obtain field permeability and infiltration rates. Infiltration test results may be applied to infiltration theory. Data from infiltration tests may be verified using available soil water storage computed from soil parameters. The effect of soil cover conditions is noted and investigated using the drum infiltrometer. Storm observations are used to confirm infiltration models. Infrequency of rainfall activity limited the number and reliability of observations. The effects of precipitation frequency and input intensity to the pond also noted in storm observations. A design procedure incorporating infiltration in stormwater retention basins is presented. This design procedure is based on infiltration theory and observed pond operation.

During the 1990s, shellfish hatcheries operating on the Eastern Shore of Virginia noticed an increase in mortalities of their clam larvae; it was suspected that this was a result of the deteriorating quality of the estuarine water used by aquaculture hatcheries. Many hatcheries obtain their facility process water directly from nearby streams and estuaries. During the same time period, there was also an increase in the use of plastic mulch on some of the vegetable fields on the Eastern Shore. The increased runoff commonly associated with these plastic-covered fields often contains copper-based bactericides that are used on the crops. The plasticulture fields were often located adjacent to the same estuaries from which the shellfish hatcheries draw their water. High levels of copper were measured in multiple surface water locations near these fields. Runoff associated with the plasticulture fields contained up to 238 ug/L dissolved copper, well in excess of the copper concentration of 16.4 ug/L dissolved copper known to affect the mortality of larval clams. Surface water samples collected from nearby unimpacted water bodies contained less than 4 ug/L dissolved copper. Sorption studies conducted with synthetic estuary water quantified the dissolved copper sorption capacities of eight sorbents, including GACs, zeolites, a greensand, and an ion exchange resin, Amberlite IRC-718. These isotherm studies showed that all sorbents removed soluble copper, and that increased salinity and a greater contact time were shown to increase sorption. Utilizing the Freundlich isotherm, the capacity of the eight sorbents studies ranged from 25 to 221 ug/g with a 24-hour contact time. Column studies with an influent concentration of 300 ug/L dissolved copper showed that using 10 grams of a GAC sorbent, a flow rate of 5 mL/min maintained the target effluent concentration of less than 16.4 ug/L for approximately 100 hours. A similar column using 10 g of resin sorbent at a flow rate of 12.5 mL/min maintained the target effluent concentration for approximately 300 hours. The high removal capacity of the resin makes it a desirable treatment for controlling copper in estuarine water used for aquaculture. Utilizing the sorbent capacities obtained from the Freundlich isotherm and a batch treatment, a typical 500 gallon tank used for clam aquaculture would require approximately four pounds of a GAC sorbent, or two pounds of the resin sorbent to reduce a source water that contains 300 ug/L of dissolved copper to below the larval clam toxicity level. Both sorbents would require a 24-hour contact time. / Master of Science

In many experiments, surfactant adsorption and desorption at solid-liquid interfaces is found to be quite slow, considering that surfactants are small molecules. Attenuated total reflectance Fourier transform infrared spectroscopy was used to study the adsorption, desorption, and exchange of tetradecyltrimethylammonium bromide (C₁₄TABr) at the silicon oxide surface. The exchange of surfactant was monitored using protonated and perdeuterated C₁₄TABr. The data show that exchange of C₁₄TABr between the surface and the bulk solution is very fast, complete exchange occurs in less than 10 seconds. A simple exchange model suggests that the disassociation rate constant of a single monomer is no less than 1 s^-1, which is ~ 10⁴ times slower than monomer exchange in bulk solutions. The actual exchange rate may be greater than observed in the present work due to transport phenomena. The rates of exchange are similar at concentrations above and below the critical micellar concentration. Adsorption is similarly rapid, but under some circumstances there is a small residue of surfactant that is slow to desorb. Desorption experiments utilizing KBr solutions of high and low ionic strength show that two thirds of each adsorbed micelle is held by hydrophobic association, and the other third is electrostatically bound. Adsorption, desorption, and exchange experiments at temperatures of 11°C above and 8°C below the Krafft temperature (14.4°C) show similar kinetics. / Master of Science

Les vapeurs organiques émises des solvants utilisés dans le produit chimique / la nourriture / les processus pharmaceutiques, ou des stations d'entreposage de combustible d'hydrocarbure aux terminus de pétrole, peuvent être efficacement capturées par l'adsorption sur les lits de charbon actif. L'objectif général du programme de recherche est les études expérimentales et les études de simulation de l'adsorption et des pas de régénération en cas de l'enlèvement COV qui estime dans les émissions industrielles par l'Adsorption (TSA – Température Swing Adsorption et VTSA -Vacuum Température Swing Adsorption). C'est accompli par les points suivants : établir les données d'équilibre d'isotherme pour 5 COV et 8 carbones activés à 293, 313, 333 et 353 K (complètement 120 expériences d'isotherme) et les utiliser ensuite dans le modèle de simulation; développer une simulation pose pour le processus de régénération et l'adsorption; concevoir et optimiser l' expérimentale de TSA qui a été établi dans Ecole des les Mines de Nantes; concevoir et optimiser l'expérimentale de VTSA qui a été établi dans GRL ARKEMA; la validation de simulation de résultats expérimentaux de le processus TSA et VTSA. Une fois après l'achèvement de tous les objectifs, le but est de se développer et le lancement un utile de simulation complet pour l'adsorption et les pas de régénération de COV avec la coopération de la Société PROSIM. / Organic vapors emitted from solvents used in chemical / food / pharmaceutical processes, or from hydrocarbon fuel storage stations at oil terminals, can be efficiently captured by adsorption onto activated carbon beds. The overall objective of the research program is the experimental and simulation studies of the adsorption and regeneration steps in the case of VOC removal which accounts into industrial emissions by Temperature Swing Adsorption (TSA) and Vacuum Temperature Swing Adsorption (VTSA) processes. This is achieved by the following steps : to establish the isotherm equilibrium data for 5 VOCs and 8 activated carbons at 293, 313, 333, and 353 K (totally 120 isotherm experiments) and then use them in the simulation model; to develop a simulation model for adsorption and regeneration process; to design and optimize the experimental setup of Thermal Swing Adsorption (TSA) which has been established in Ecole des Mines de Nantes; to design and optimize the experimental setup of Vacuum Temperature Swing Adsorption processes (VTSA) which has been established in GRL ARKEMA unit ; simulation validation of experimental results of TSA and VTSA process. Once after the completion of all the objectives, the goal is to develop and launch a complete simulation package for adsorption and regeneration steps of VOCs with the co-operation from PROSIM Corporation.

Adsorption/desorption behaviors of three volatile organic compounds (VOCs) emitted from the optoelectronics industry by Y-type and ZSM-5 zeolites were studied in this work. Target VOCs include acetone, isopropyl alcohol (IPA), and propylene glycol monomethyl ether acetate (PGMEA). Adsorption/desorption experiments were conducted in a fixed-bed column using various operating conditions to mimic the commercial ones. Also studied include the adsorption kinetics for single-component, two-component, and three-component cases. Experimental results of the single-adsorbate case by both model zeolites have shown that the amount of VOC adsorbed follows the order of PGMEA > IPA > Acetone. This is ascribed to the greatest molecular weight of PGMEA among three VOCs tested. The adsorption capacity of each zeolite for each target VOC was found to increase with its increasing initial concentration. Freundlich isotherm and Langmuir isotherm were found to be suitable for describing the adsorption behaviors for the single-adsorbate case. Results of the desorption experiments also showed that most of the target VOCs could be desorbed at 180¢J in 100 minutes. The adsorption capacities of the regenerated model zeolites were found to be decreasing as the regeneration times increased. As compared with the fresh ones, the regenerated zeolites had reduced specific surface areas, but increased pore sizes. In addition, the Yoon and Nelson equation was employed to study the kinetic behaviors of adsorbing the target VOCs by the model zeolites. A good agreement of the experimental results and predictions by the Yoon & Nelson model was obtained for the single-adsorbate case. However, the Yoon and Nelson model was found to be incompetent to simulate and predict all the multi-adsorbate cases including two-component adsorption and three-component adsorption in this work. Again, it is speculated that the displacement of lower-molecular-weight adsorbates (i.e., acetone and IPA) by PGMEA (an adsorbate of a much greater molecular weight) would be responsible for this finding. For the two-adsorbate case, nevertheless, the Yoon and Nelson equation was found to be capable of describing the adsorption behavior under the circumstance of C/C0 < 1.

M. Tech. Chemical Engineering. / Discusses the reactive properties of oxalate molecules on the surface of activated carbons (ACs) so that they can bind selectively with base metals. Therefore, the experimental plan covered three main axes of study: Chemical modification of AC adsorbent and characterization, adsorption studies in batch and continuous modes, and adsorption modelling.

In this work the magnesium, zinc, nickel and cobalt MOFs of the MOF-74 isostructural family are used to probe metal-dependent adsorbate interactions with water and with carbon monoxide because of their ability to generate open metal sites upon activation. An isostructural family is used so that the only variable from one MOF to another is the metal incorporated into the framework. For water adsorption isotherms with humidities up to 90%, the observed trend at 298K and 1 bar is Mg-MOF-74 > Zn-MOF-74 > Co-MOF-74 > Ni-MOF-74. This observed trend is due to Lewis acid-base interactions. When the weight effect is removed, differences are still observed, especially below 40% relative humidity, thereby confirming that there is a metal effect. These studies revealed that PXRD alone cannot indicate the level of structural decomposition and that none of the four isostructures fully retain their structural integrity on exposure to humidified air because of microstrain and/or the presence of oxygen; more studies examining the extent of structural decomposition need to be undertaken. For carbon monoxide adsorption the general observed trend for P < 4 bar and temperatures of 298, 313 and 333K is Co-MOF-74 > Ni-MOF-74 > Zn-MOF-74 > Mg-MOF-74. This trend is based on π-backbonding interactions. Here again, differences remain after removal of the weight effect, confirming the metal dependence. Notably, Co-MOF-74 has the highest CO loading at 298K and 1 bar reported so far. Both the Toth and Virial Isotherms were used to fit the CO adsorption data followed by the use of the Clausius-Clapeyron equation to find the isosteric heats of adsorption, qst. The results from the Toth isotherm are more reliable and showed that qst remains constant as loading increases for Mg-MOF-74, decreases for Zn-MOF-74 and increases with loading for Co-MOF-74 and Ni-MOF-74; Ni-MOF-74 had the highest heat of adsorption at all loadings. It appears that using the Clausius-Clapeyron equation to calculate qst is an inappropriate method for Ni-MOF-74 so other methods such as calorimetry are recommended. It is also recommended to model the data of all the MOFs with other isotherm models such as Sips equation and to investigate the possibility of chemisorption for the cobalt and nickel isostructures. Finally, Henry’s constant results reveal that Ni-MOF-74 has the highest affinity for CO at low coverages.

Os resíduos sólidos da indústria coureira são produzidos em diferentes etapas de limpeza, classificação e ajuste da espessura do couro, e são classificados como perigosos quando gerados nas etapas posteriores ao curtimento com cromo. Os resíduos que já passaram pela etapa de curtimento apresentam elevada estabilidade, não sendo facilmente degradados. Além disso, nas etapas do acabamento molhado do couro, em especial no tingimento, corantes são utilizados para conferir cor aos artigos. Devido à necessidade de utilização de água e corantes em excesso, são gerados, nessas etapas, efluentes coloridos. Esses efluentes possuem quantidades elevadas de substâncias solúveis e coloridas que, devido ao seu potencial recalcitrante, não são facilmente removidas em sistemas convencionais de tratamento de efluentes. Neste trabalho, é apresentada uma nova proposta para o uso dos resíduos sólidos da indústria coureira antes de seu destino final, possibilitando assim uma sobrevida a esses resíduos como adsorventes alternativos de substâncias presentes em efluentes industriais do processamento do couro, em especial, os corantes oriundos das operações de acabamento molhado, com perspectivas ao reuso dos efluentes. Os efluentes oriundos da etapa de acabamento molhado de couro em escala piloto foram caracterizados. Assim, soluções aquosas sintéticas no intervalo de concentrações de corantes de efluentes foram preparadas e foi avaliada a capacidade de adsorção de dois tipos de resíduos de couro (curtido ao cromo e vegetal) em diferentes valores de pH. As isotermas de adsorção e cinética dos corantes Amarelo Ácido 194, Vermelho Ácido 357 e Preto Ácido 210 foram obtidos para os resíduos de couro curtido ao cromo no pH ideal de adsorção (entre 2 e 3). Além disso, a remoção do corante presente em efluente de tingimento (obtido em escala piloto) foi otimizada utilizando técnicas sequenciais de planejamento de experimentos. As isotermas apresentaram diferentes comportamentos, sendo do tipo C1, H2 e H3/L3 para os corantes Amarelo 194, Vermelho 357 e Preto 210, respectivamente. Os estudos dos mecanismos de transferência de massa demonstraram que a adsorção do corante Amarelo 194 é controlada pela transferência de massa na camada limite, enquanto que para os corantes Vermelho 357 e Preto 210 também foi observada a difusão no interior da partícula. Para esses dois últimos corantes, as difusividades foram da ordem de 10-9 e 10-11 m2 min-1. Os dados termodinâmicos, associados a análises instrumentais, confirmaram a natureza de adsorção por interações entre os grupos SO3 - e NO2 - dos corantes com os grupos NH(n) + do couro. Para a remoção do corante Vermelho 357 de efluentes de tingimento, uma região de ótimo foi observada para capacidade de adsorção no equilíbrio, correspondente ao pH 3,0 e temperatura entre 16 e 18 °C, sendo obsevado aproximadamente 74 mg g-1 para a concentração de 6,0 g L-1 de adsorvente. Entretanto, na região de estudo não foi observado região de ótimo para a remoção, sendo que para isso seria necessário um deslocamento no planejamento para pH inferiores a 3 e temperaturas superiores a 35 °C, o que de certa forma é inviável. Observouse que a máxima remoção em pH 3 e 35 °C foi de 75 %. O processo de remoção do corante por adsorção foi capaz ainda de reduzir a toxicidade do efluente em cerca de 90 %. / The solid wastes from the tannery industry are produced in different steps of cleaning, sorting and adjusting the thickness of the leather, and they are classified as hazardous waste when they are produced after chrome tanning. The tanned leather wastes present high stability and are not easily degraded. Moreover, in the wet leather finish, particularly during the dyeing process, dyes are used to color the items. Due to the need of using water and dye in excess, colored effluents are generated in these steps. These effluents have high amounts of soluble and colored substances that, due to their recalcitrant potential, are not easily treated in conventional eflluent treatment systems. In this research, a new proposal for the use of solid waste in the leather industry before its final destination is presented, which enables the reuse of these wastes as alternative adsorbents of substances in industrial effluents from the leather processing, particularly dyes derived from wet finishing operations, with the aim of reusing the wastewater. The effluents from the wet leather finish steps in a pilot scale were characterized. Thus, aqueous synthetic solutions in the concentration range of effluent dyes were prepared and the adsorption capacity of two types of leather waste (chrome tanned and vegetable leather) was evaluated at different pH values. Adsorption isotherms and kinetics of Acid Yellow 194, Acid Red 357 and Acid Black 210 dyes were obtained for chrome tanned leather waste in optimal adsorption pH (between 2 and 3). Furthermore, the removal of the dyes in deing wastewater (obtained in a pilot scale) was optimized by using sequential experimental design techniques. The isotherms presented different results: C1, H2 and H3/L3 types for the Yellow 194, Red 357 and Black 210 dyes, respectively. Studies on the mechanisms of mass transfer have shown that the adsorption of the Yellow 194 dye is controlled by mass transfer in the boundary layer, whereas in Red 357 and Black 210 dyes a diffusion was also observed inside the particle. For these last two dyes, diffusivities were 10-9 and 10-11 m2 min-1. The thermodynamic data, associated with instrumental analysis, confirmed the nature of adsorption by interactions between the NO2 - and SO3 - groups of the dyes with the NHn + groups of the leather. For removing the Red 357 dye in dyeing effluents, an optimum region was observed for the adsorption capacity in equilibrium, which corresponds to pH 3.0 to 3.2 and temperature between 16 and 18 °C, with about 74 mg g-1 for the concentration of 6.0 g L-1 adsorbent. However, in the study region an optimum region for the removal was not observed, and this would require a shift in planning for pH below 3 and temperatures above 35 °C, which is somewhat impractical. It was observed that the maximum removal at pH 3 and 35 °C was 75 %. The removing process the dye by adsorption was also able to reduce the toxicity of the effluent by about 90 %.

Os resíduos sólidos da indústria coureira são produzidos em diferentes etapas de limpeza, classificação e ajuste da espessura do couro, e são classificados como perigosos quando gerados nas etapas posteriores ao curtimento com cromo. Os resíduos que já passaram pela etapa de curtimento apresentam elevada estabilidade, não sendo facilmente degradados. Além disso, nas etapas do acabamento molhado do couro, em especial no tingimento, corantes são utilizados para conferir cor aos artigos. Devido à necessidade de utilização de água e corantes em excesso, são gerados, nessas etapas, efluentes coloridos. Esses efluentes possuem quantidades elevadas de substâncias solúveis e coloridas que, devido ao seu potencial recalcitrante, não são facilmente removidas em sistemas convencionais de tratamento de efluentes. Neste trabalho, é apresentada uma nova proposta para o uso dos resíduos sólidos da indústria coureira antes de seu destino final, possibilitando assim uma sobrevida a esses resíduos como adsorventes alternativos de substâncias presentes em efluentes industriais do processamento do couro, em especial, os corantes oriundos das operações de acabamento molhado, com perspectivas ao reuso dos efluentes. Os efluentes oriundos da etapa de acabamento molhado de couro em escala piloto foram caracterizados. Assim, soluções aquosas sintéticas no intervalo de concentrações de corantes de efluentes foram preparadas e foi avaliada a capacidade de adsorção de dois tipos de resíduos de couro (curtido ao cromo e vegetal) em diferentes valores de pH. As isotermas de adsorção e cinética dos corantes Amarelo Ácido 194, Vermelho Ácido 357 e Preto Ácido 210 foram obtidos para os resíduos de couro curtido ao cromo no pH ideal de adsorção (entre 2 e 3). Além disso, a remoção do corante presente em efluente de tingimento (obtido em escala piloto) foi otimizada utilizando técnicas sequenciais de planejamento de experimentos. As isotermas apresentaram diferentes comportamentos, sendo do tipo C1, H2 e H3/L3 para os corantes Amarelo 194, Vermelho 357 e Preto 210, respectivamente. Os estudos dos mecanismos de transferência de massa demonstraram que a adsorção do corante Amarelo 194 é controlada pela transferência de massa na camada limite, enquanto que para os corantes Vermelho 357 e Preto 210 também foi observada a difusão no interior da partícula. Para esses dois últimos corantes, as difusividades foram da ordem de 10-9 e 10-11 m2 min-1. Os dados termodinâmicos, associados a análises instrumentais, confirmaram a natureza de adsorção por interações entre os grupos SO3 - e NO2 - dos corantes com os grupos NH(n) + do couro. Para a remoção do corante Vermelho 357 de efluentes de tingimento, uma região de ótimo foi observada para capacidade de adsorção no equilíbrio, correspondente ao pH 3,0 e temperatura entre 16 e 18 °C, sendo obsevado aproximadamente 74 mg g-1 para a concentração de 6,0 g L-1 de adsorvente. Entretanto, na região de estudo não foi observado região de ótimo para a remoção, sendo que para isso seria necessário um deslocamento no planejamento para pH inferiores a 3 e temperaturas superiores a 35 °C, o que de certa forma é inviável. Observouse que a máxima remoção em pH 3 e 35 °C foi de 75 %. O processo de remoção do corante por adsorção foi capaz ainda de reduzir a toxicidade do efluente em cerca de 90 %. / The solid wastes from the tannery industry are produced in different steps of cleaning, sorting and adjusting the thickness of the leather, and they are classified as hazardous waste when they are produced after chrome tanning. The tanned leather wastes present high stability and are not easily degraded. Moreover, in the wet leather finish, particularly during the dyeing process, dyes are used to color the items. Due to the need of using water and dye in excess, colored effluents are generated in these steps. These effluents have high amounts of soluble and colored substances that, due to their recalcitrant potential, are not easily treated in conventional eflluent treatment systems. In this research, a new proposal for the use of solid waste in the leather industry before its final destination is presented, which enables the reuse of these wastes as alternative adsorbents of substances in industrial effluents from the leather processing, particularly dyes derived from wet finishing operations, with the aim of reusing the wastewater. The effluents from the wet leather finish steps in a pilot scale were characterized. Thus, aqueous synthetic solutions in the concentration range of effluent dyes were prepared and the adsorption capacity of two types of leather waste (chrome tanned and vegetable leather) was evaluated at different pH values. Adsorption isotherms and kinetics of Acid Yellow 194, Acid Red 357 and Acid Black 210 dyes were obtained for chrome tanned leather waste in optimal adsorption pH (between 2 and 3). Furthermore, the removal of the dyes in deing wastewater (obtained in a pilot scale) was optimized by using sequential experimental design techniques. The isotherms presented different results: C1, H2 and H3/L3 types for the Yellow 194, Red 357 and Black 210 dyes, respectively. Studies on the mechanisms of mass transfer have shown that the adsorption of the Yellow 194 dye is controlled by mass transfer in the boundary layer, whereas in Red 357 and Black 210 dyes a diffusion was also observed inside the particle. For these last two dyes, diffusivities were 10-9 and 10-11 m2 min-1. The thermodynamic data, associated with instrumental analysis, confirmed the nature of adsorption by interactions between the NO2 - and SO3 - groups of the dyes with the NHn + groups of the leather. For removing the Red 357 dye in dyeing effluents, an optimum region was observed for the adsorption capacity in equilibrium, which corresponds to pH 3.0 to 3.2 and temperature between 16 and 18 °C, with about 74 mg g-1 for the concentration of 6.0 g L-1 adsorbent. However, in the study region an optimum region for the removal was not observed, and this would require a shift in planning for pH below 3 and temperatures above 35 °C, which is somewhat impractical. It was observed that the maximum removal at pH 3 and 35 °C was 75 %. The removing process the dye by adsorption was also able to reduce the toxicity of the effluent by about 90 %.