Personal Research Database

Full Text: J\J Haz Mat48, 171.pdf

Abstract: Inactivated copper-sensitive and copper-tolerant strains of Mucor rouxii cultured at high copper concentration were tested for their potential to adsorb Cu(II) ions from solution. We performed batch experiments to determine the pH profile for Cu(II) binding, binding capacity, and the possibility of removing the Cu(II) that had been adsorbed. The biomasses studied showed a high affinity for Cu(II) ions as the pH increased from 2 to 5. The copper-tolerant strain exhibited a higher copper adsorption than the copper-sensitive strain. Most of the Cu(II) adsorbed by the inactivated cells was desorbed by treatment with 0.1 M HCl. We investigated one of the mechanisms involved in Cu(II) binding through chemically modifying the possible carboxyl groups present on the inactivated cells of Mucor rouxii by esterification with methanol. Cu(II) binding decreased approximately 25% after the carboxyl groups were esterified. The Cu(II) binding ability of the esterified carboxyl groups was regained after base hydrolysis. These preliminary findings suggest that the carboxyl groups could be one of the mechanisms responsible for Cu(II) binding. This phenomenon can have useful applications for metal removal from contaminated water.

Keywords: Mucor Rouxii, Fungi, Copper, Metal Binding, Metal-Contaminated Water, Rhizopus-arrhizus Biomass, Fungal Biomass, Heavy-Metals, Sorption

Gardea-Torresdey, J.L., Tiemann, K.J., Gonzalez, J.H., Henning, J.A. and Townsend, M.S. (1996), Ability of silica-immobilized Medicago sativa (alfalfa) to remove copper ions from solution. Journal of Hazardous Materials, 48 (1-3), 181-190.

Full Text: J\J Haz Mat48, 181.pdf

Abstract: Preliminary screening laboratory batch experiments to determine the binding ability of seven different populations of Medicago sativa (alfalfa) showed good copper binding characteristics of the biomasses studied. All seven populations examined had similar trends for binding copper as a function of pH. The copper binding by the different alfalfa populations occurred within 5 min. All the alfalfa biomasses showed high copper binding, but the capacities varied according to the alfalfa sample studied. The pH dependence of the copper ion binding to the alfalfa biomasses suggested that it might be possible to recycle the system much like an ion-exchange resin. However, the alfalfa cells cannot be packed into a column because the cells clump together and restrict the flow. We immobilized the cells of Malone alfalfa shoots in a silica matrix. Column experiments for copper binding by the silica immobilized alfalfa demonstrated that the alfalfa tissues were capable of removing considerable amounts of copper ions under flow conditions. After every copper binding cycle most of the copper was desorbed with a few bed volumes of 0.1 M HCl. Our work indicates that the Malone-silica preparations are highly durable. We subjected the biomaterial to as many as 10 cycles of binding and elution without observing any significant decrease in copper binding capacity.

Keywords: Biofiltration, Phytoremediation, Medicago Sativa, Alfalfa, Copper, Removal, Recovery, Cadmium, Binding, Water, Poly(Gamma-Glutamylcysteinyl)Glycine, Adsorption, Biomass, Metals, Roots, Zinc

Gardea-Torresdey, J.L., Tang, L. and Salvador, J.M. (1996), Copper adsorption by esterified and unesterified fractions of sphagnum peat moss and its different humic substances. Journal of Hazardous Materials, 48 (1-3), 191-206.

Full Text: J\J Haz Mat48, 191.pdf

Abstract: The Cu(II) binding properties of Canadian Sphagnum peat moss, humic acid and humin extracted from the peat moss were investigated. Batch pH profile experiments indicated that the adsorption of Cu(II) is pH dependent. At pH 4.0 and 5.0 about 99% of Cu(II) was bound by all three biomasses. Time-dependent experiments showed that the binding of Cu(II) is very rapid. The Cu(II) binding capacities at pH 4.0 were 16.1 mgper gram peat moss, 28.2 mgper gram humic acid and 17.9 mgper gram humin. More than 90% of Cu(II) bound to the biomasses was recovered by treatment with 0.1 M HCl. We showed that carboxyl groups on these humic substances are responsible for some of the Cu(II) binding by esterifying them with methanol in the presence of trimethoxymethane (trimethyl orthoformate) and observing a decrease in Cu(II) binding. Infrared analysis confirmed the esterification and base hydrolysis of the esterified biomasses corroborated that esterification (and not degradation) had occurred since the metal-binding ability was regained. Our results provide important information on the interaction of Cu(II) ions with Sphagnum peat moss and its humic fractions. This may have practical applications for the removal of hazardous copper ions from contaminated water supplies. Reprinted by permission of the Publisher.

Keywords: Humic Substances, Sphagnum, Peat Moss, Humic Acids, Humin, Copper(II) Binding, Esterification

Chitra, S., Sekaran, G. and Chandrakasan, G. (1996), Adsorption of a mutant strain of Pseudomonas pictorum on rice bran based activated carbon. Journal of Hazardous Materials, 48 (1-3), 239-250.

Full Text: J\J Haz Mat48, 239.pdf

Abstract: Microbial cultures immobilised on various matrices are used to protect the microbes from confronting shock loads of concentrated organic pollutants during wastewater treatment. Activated carbon is generally used as carrier material in comparison to other matrices. In this study a mutant strain of Pseudomonas pictorum (MU 174) was immobilised on rice bran based activated carbon. The effect of contact time, pH, mass of activated carbon, temperature and ionic strenth on adsorption of µ174 on to activated carbon has been investigated. The optimum temperature and pH for adsorption of µ174 on to activated carbon were 31C and 7, respectively. The adsorption kinetic parameters K_p, K_ad and H have been determined. The rate constant values and the intraparticle diffusion of 174 on to activated carbon obtained were 510^-3-17.510^-3 min^-1 and 0.75-2.9 min^0.5, respectively and the enthalpy of adsorption was observed to be-47.9 kJ/Avogadro number of cells.

Keywords: Rice Bran Based Activated Carbon, Mutant Strain of P-Pictorum, Adsorption Isotherm, Intraparticle Diffusion, Degradation, Phenol, Microorganisms, Surfaces, Bed

? Aminabhavi, T.M., Phayde, H.T.S., Ortego, J.D. and Rudzinski, W.E. (1996), Molecular migration of hazardous liquids into thermoplastic ethylene-propylene random copolymer and isotactic polypropylene membranes. Journal of Hazardous Materials, 49 (2-3), 125-141.

Full Text: 1996\J Haz Mat49, 125.pdf

Abstract: The molecular migration of hazardous organic halocarbons into thermoplastic polymer blend membranes has been studied using a gravimetric technique. From the sorption results, the diffusion and permeation of liquids have been calculated. Molecular migration depends on the nature of the halocarbons, membrane-solvent interactions, temperature, and availability of free volume within the membrane matrix. The size and the polarity of liquids do not show any systematic effect on sorption and desorption phenomena. The liquid migration results have been analyzed using a Fickian mechanism of sorption and diffusion. A numerical method based on the finite difference approach has been used to compute the liquid concentration profiles in the membrane materials. The estimated Arrhenius activation energy for diffusion and the heat of sorption are indicative of the nature of the liquids and their interactions with the membrane. The rate of evaporation of liquids has been calculated for sorption and desorption runs, and these results depend on the volatility of the halocarbons.

Keywords: Absorption, Activation, Activation Energy, Aliphatic Alkanes, Desorption, Difference, Diffusion, Diffusion Coefficient, Evaporation, Fickian, Hazardous Liquid, Interactions, Mechanism, Membrane, Membranes, Migration, Penetrant Transport, Permeation, Polymer, Polymer Membranes, Polystyrene, Profile, Rubber, Santoprene, Sorption, Technique, Temperature

? Joshi, M.M. and Lee, S. (1996), Coal agloflotation: a remediation technique for cleaning of town gas soils. Journal of Hazardous Materials, 49 (2-3), 155-163.

Full Text: 1996\J Haz Mat49, 155.pdf

Abstract: The use of a “clean” fuel and the treatment of contaminated soils are two factors that can greatly improve the environment. Coal, which occurs in great abundance in the USA, is widely used both in the small-scale domestic and in the large-scale industrial market. Apart from high sulfur content, a high ash content of coal is undesirable. Soils contaminated with polycyclic aromatic hydrocarbons (PAHs) are a potential threat to health and the environment and need to be treated. The present study investigates the use of a hydrophobic coal surface for the adsorption and removal of oily/tarry contaminants such as PAHs from town gas soils. The agloflotation process uses a coal-soil-water mixture to achieve simultaneous removal of mineral matter from coal. The cobeneficiation achieves 90% and higher decontamination for soil and 40% and higher ash removal from coal.

Keywords: Adsorption, Agloflotation, Clean Soil Process, Coal Beneficiation, Contaminants, Environment, Factors, Fuel, Health, Hydrocarbons, Hydrophobic, Market, Need, PAHs, Polycyclic Aromatic Hydrocarbon, Polycyclic Aromatic Hydrocarbons, Process, Remediation, Removal, Soil, Soils, Sulfur, Surface, Technique, Treatment, USA

Lu, Y. and Wilkins, E. (1996), Heavy metal removal by caustic-treated yeast immobilized in alginate. Journal of Hazardous Materials, 49 (2-3), 165-179.

Full Text: J\J Haz Mat49, 165.pdf

Abstract: Saccharomyces cerevisiae yeast biomass was heated in 0.75 M NaOH at 70-90°C for 10-15 min to increase its biosorption for heavy metals, and then immobilized in alginate gel. Biosorption for Cu²⁺, Cd²⁺ and Zn²⁺ on alginate gel, native yeast, native yeast immobilized in alginate gel, and caustic-treated yeast immobilized in alginate gel, were all compared. Immobilized yeasts (native yeast and caustic-treated yeast) could be reactivated and reused in a manner similar to ion-exchange resins. Immobilized caustic-treated yeast has high heavy metal biosorption capacity and high metal removal efficiency over a rather wide pH region. The biosorption isotherm of immobilized caustic-treated yeast was studied and empirical equations were obtained. The initial pH of polluted water affected the metal removal efficiency in extreme pH regions, and the biosorption capacity almost remained constant over a wide pH range. The equilibrium biosorption appeared to be temperature independent in the range from 7°C to 45°C at low initial metal concentration. (C) 1996 Elsevier Science Ltd. All rights reserved.

Keywords: Alginate, Biosorption, Caustic-Treated, Heavy Metal, Immobilization, Removal, Yeast

Gardea-Torresdey, J.L., Tiemann, K.J., Gonzalez, J.H., Cano-Aguilera, I., Henning, J.A. and Townsend, M.S. (1996), Removal of nickel ions from aqueous solution by biomass and silica-immobilized biomass of Medicago sativa (alfalfa). Journal of Hazardous Materials, 49 (2-3), 205-216.

Full Text: J\J Haz Mat49, 205.pdf

Abstract: The characteristics of the roots and shoots from seven different populations of Medicago sativa (alfalfa) were examined for their ability to bind nickel ions from aqueous solution. Batch laboratory experiments were performed to determine the optimal pH for nickel binding to the alfalfa plant tissues which was between pH 5 and 6. From these experiments, pH profiles were performed to gain information about the chemical functional groups in the alfalfa plant tissues responsible for the nickel binding. Binding time dependency studies determined that approximately 80% of the nickel ions bound to the alfalfa plant tissues in less than 5 min. Binding capacity experiments showed that nickel binding was as much as 4.1 mg of nickel per gram of alfalfa biomass. Nickel recovery experiments showed that more than 90% of the bound nickel was removed from the alfalfa biomass. Column experiments were conducted to examine the binding of nickel to silica immobilized alfalfa plant tissues under flow conditions. Results from these experiments showed that more than 90% of the retained nickel was recovered after four bed volumes of 0.1 M HCl solution were passed through the column. After 12 cycles on the same column, the efficiency for nickel removal and recovery from solution was stable. (C) 1996 Elsevier Science Ltd. All rights reserved.

Keywords: Biofiltration, Phytoremediation, Alfalfa, Medicago sativa, Nickel, Binding, Recovery

Abuzaid, N.S. and Nakhla, G.F. (1996), Effect of solution pH on the kinetics of phenolics uptake on granular activated carbon. Journal of Hazardous Materials, 49 (2-3), 217-230.

Full Text: J\J Haz Mat49, 217.pdf

Abstract: The impact of solution pH on the kinetics of adsorption and adsorption-reaction combination of phenol and o-cresol on Granular Activated Carbon (GAC) was evaluated at room temperature (21°C). Batch experiments were performed under oxic and anoxic conditions at pH values of 3, 7, and 11. The results showed that the equilibration time for physical adsorption increased with the increase in pH and occurred in the time range of (7.5-11) days for the adsorption-reaction combination (oxic cases). The polymerization reactions lagged by about 10 h under all of the pH values. Diffusivity coefficients in the oxic cases increased inversely with pH while the highest difference between oxic and anoxic diffusivities was observed at neutral pH. The homogeneous surface diffusion model (HSDM) predicted accurately the anoxic batches and deviated from the oxic data under all pH conditions. Under controlled dissolved oxygen and pH conditions, the isotherm and batch equilibrium capacities matched with maximum deviation of 4%. The effect of solution pH on the rate of the DO-induced enhancement was found to follow a simplified form of self retardant reaction model. The aforementioned model showed strong predictive capability for the formation of polymers with time. (C) 1996 Elsevier Science Ltd. All rights reserved.

Keywords: Activated Carbon, Kinetics, pH, Phenolic, Dissolved Oxygen, Polymer, Modeling

? Campagnolo, J.F. and Akgerman, A. (1996), A prediction method for gas-phase VOC isotherms onto soils and soil constituents. Journal of Hazardous Materials, 49 (2-3), 231-245.

Full Text: 1996\J Haz Mat49, 231.pdf

Abstract: Similarities in the adsorption isotherms of various non-polar volatile organic chemicals (VOCs) on dry soils and clay minerals are used to develop an empirical predictive method to estimate the isotherm parameters of the BDDT (three-parameter BET) model. Single-component adsorption data of nine VOCs on both soils and clay minerals and also nitrogen adsorption are examined. The familiar practice of reducing isotherms by the BET monolayer coverage is applied, and it is shown that isotherms of different VOCs on the same adsorbent collapse into a single isotherm. A simple prediction method based on this observation is presented.

Keywords: Adsorbent, Adsorption, Adsorption Isotherm, Adsorption Isotherms, Clay, Clay Minerals, Coverage, Gas Phase, Gas-Phase, Isotherm, Isotherms, Model, Monolayer, Nitrogen, Observation, Organic Vapors, Practice, Prediction, Prediction Method, Soil, Soils, Sorption, Surface, VOC, VOCs, Volatile Organic Chemical, Water

? McFarland, M.J., Beck, M., Harper, S. and Deshmuck, K. (1996), Anoxic treatment of trifluralin-contaminated soil. Journal of Hazardous Materials, 50 (2-3), 129-141.

Full Text: 1996\J Haz Mat50, 129.pdf

Abstract: Amending anoxic soils with stoichiometric amounts of sodium acetate led to the complete transformation of trifluralin within the 45 day treatment period, Under these conditions, a maximum trifluralin transformation rate of 4.9 mg kg^-1 of soil per day was estimated, which corresponded to a chemical half life of 11.9 days. Regression analyses indicated that the zero order rate model provided the best fit to the experimental data, suggesting that the trifluralin transformation rate is independent of concentration during acetate addition. Using radiolabeled trifluralin, it was determined that the principal contaminant transformation mechanisms were degradation and bound residue formation (i.e., irreversible adsorption). Volatilization and mineralization of trifluralin were found to be negligible over the 45 day treatment period. Using poisoned controls, it was determined that trifluralin transformation under acetate-amended conditions was biologically mediated, Amending trifluralin contaminated soils with stoichiometric amounts of iron sulfide resulted in complete trifluralin transformation within 24 hours of treatment. A maximum trifluralin transformation rate of 380 mg kg^-1 of soil per day was estimated for this system, which corresponded to a chemical half life of 4.4 h. The rates of trifluralin transformation followed the first-order kinetic model during iron sulfide addition. Using radiolabeled trifluralin, it was found that chemical degradation was the principal removal mechanism. Neither volatilization nor mineralization was found to be a significant contaminant removal mechanism during iron sulfide treatment. Poisoned controls indicated that trifluralin transformation was mediated primarily by an abiotic chemical reaction mechanism. Additional study is required to clarify the rate limiting steps so that full scale soil treatment systems may be properly designed.

Keywords: Acetate, Adsorption, Anoxic, Chemical Reaction, Contaminant, Day Treatment, Degradation, First-Order Kinetic Model, Iron, Iron Sulfide, Irreversible Adsorption, Kinetic, Kinetic Model, Life, Mechanism, Mechanisms, Mineralization, Model, Removal, Removal Mechanism, Scale, Soil, Soil Treatment, Soils, Systems, Transformation, Treatment, Trifluralin, Volatilization

? Arocha, M.A., Mccoy, B.J. and Jackman, A.P. (1996), VOC immobilization in soil by adsorption, absorption and encapsulation. Journal of Hazardous Materials, 51 (1-3), 131-149.

Full Text: 1996\J Haz Mat51, 131.pdf

Abstract: Immobilization of volative organic compounds (VOCs) in contaminated soils by solidification/stabilization (S/S) processes is an attractive potential remediation process. The objectives of this study were as follows: to evaluate S/S procedures, including a new process with a VOC absorbent and silica coatings; to apply a straightforward and inexpensive analytical technique for characterizing VOC behavior during processing; and to propose the expanded use of waste materials such as contaminated soil, rice hulls, and shredded-tire particles. We investigated how the adsorbents, absorbents and encapsulating agents can be combined to retard volatilization and resist acidic aqueous leaching of toluene. The toluene released at each step of the S/S process was determined by an accurate headspace analysis method. Results showed that combining shredded-tire particles for absorption and sodium silicate for encapsulation is a promising method for immobilization of toluene in soil.

Keywords: Adsorbents, Adsorption, Adsorption and Absorption, Analysis, Behavior, Contaminated Soil, Encapsulation, Headspace Analysis, Immobilization, Leaching, Organic Compounds, Organic-Compounds, Process, Remediation, Scrap Tires, Silica, Soil, Soil Remediation, Soils, Solidification, Solidification, Stabilization, Stabilization, Technique, Toluene, VOC, VOC Immobilization, VOCs, Volatilization, Waste Materials

? Fleming, E.C., Pennington, J.C., Wachob, B.G., Howe, R.A. and Hill, D.O. (1996), Removal of N-nitrosodimethylamine from waters using physical-chemical techniques. Journal of Hazardous Materials, 51 (1-3), 151-164.

Full Text: 1996\J Haz Mat51, 151.pdf

Abstract: During the 1950s and 1960s, the Rocky Mountain Arsenal (RMA) was leased by the US Air Force for the purpose of producing rocket fuel, namely Aerozine 50, by blending hydrazine and unsymmetrical dimethyl hydrazine (UDMH). A product of the decomposition of UDMH is N-nitrosodimethylamine (NMDA). Bituminous coal granular activated carbon (GAC) systems located at the boundaries of the RMA are not highly effective at removal of NDMA. Modifications to the existing systems by adding additional adsorbents specific to NDMA removal vs construction of new facilities were evaluated. This paper summarizes the results of investigations into alternative adsorption technologies which might be more effective at removal of NDMA than bituminous coal GAC. The results were well described by the Freundlich adsorption isotherm model. Bench-scale isotherm and column studies revealed that a coconut shell GAC and carbonaceous resin were more effective at removal of NDMA than bituminous coal GAC.

Keywords: Activated Carbon, Adsorbents, Adsorption, Adsorption Isotherm, Adsorption Isotherm Model, Boundaries, Carbon, Coconut Shell, Column, Column Studies, Freundlich, Freundlich Adsorption Isotherm, Fuel, GAC, Granular Activated Carbon, Groundwater, Isotherm, Model, N-Nitrosodimethylamine, NDMA, Removal, Resin, Shell, Systems, Us, Waters

? Watts, R.J. and Dilly, S.E. (1996), Evaluation of iron catalysts for the Fenton-like remediation of diesel-contaminated soils. Journal of Hazardous Materials, 51 (1-3), 209-224.

Full Text: 1996\J Haz Mat51, 209.pdf

Abstract: The treatment of a diesel-contaminated soil with hydrogen peroxide catalyzed by six iron compounds and by naturally-occurring minerals in which the hydrogen peroxide is stabilized by phosphate was investigated using central composite rotatable experimental designs. Iron(III) perchlorate and iron(III) nitrate with 1.5 M hydrogen peroxide promoted > 99% oxidation of 1000 mg kg^-1 diesel in a Palouse loess soil. Other iron catalysts (iron(III) sulfate, iron(II) sulfate, iron(II) perchlorate) provided 70-80% diesel oxidation under similar reaction conditions. The oxidation reactions were complete within one hour and minimal desorption occurred over 90 h, suggesting that the diesel was oxidized, at least in part, in the sorbed phase. Iron(II) compounds were less effective catalysts than iron(III) species owing to the initial loss of hydrogen peroxide in oxidizing iron(II) to iron(III). The effectiveness of the iron catalysts also correlated with the lowest rates at which their anionic component quenches hydroxyl radicals. Monobasic potassium phosphate was also investigated as a mechanism to enhance the mineral-catalyzed Fenton-like remediation of diesel in the Palouse loess, but resulted in only 40% diesel loss. A central composite design used to investigate the effect of hydrogen peroxide volume on the Fenton-like remediation of the diesel-contaminated Palouse loess showed that a solution sufficient to saturate the soil (3.5 ml (5 g soil)^-1)) provided the optimum volume. Based on these optimization results, the estimated chemical cost for the remediation of 1000 mg kg^-1 diesel in the Palouse loess was $52 (907 kg)^-1 (ton).

Keywords: 2,4-D, Advanced Oxidation Process, Central Composite Design, Chemical Oxidation, Composite, Cost, Degradation, Design, Desorption, Effectiveness, Fenton Like, Fenton’s Reagent, Fenton-Like, Hydrogen Peroxide, Hydrogen-Peroxide, Hydroxyl Radicals, Iron, Loess Soil, Loss, Mechanism, Nitrate, Optimization, Oxidation, Perchlorate, Petroleum Contaminated Soil, Phosphate, Polychlorinated-Biphenyls, Potassium, Reagent, Remediation, Soil, Soil Remediation, Soils, Sorption, Sulfate, Treatment

Dural, N.H. and Chen, C.H. (1997), Analysis of vapor phase adsorption equilibrium of 1,1,1-trichloroethane on dry soils. Journal of Hazardous Materials, 53 (1-3), 75-92.

Full Text: J\J Haz Mat53, 75.pdf

Abstract: The migration and fate of volatile organic pollutants in soils are highly dependent on their vapor-phase sorptive behavior. The objective of the research presented in this paper was to investigate the vapor-phase adsorption/desorption equilibrium of 1,1,1-trichloroethane (TCA) on dry soils. A gravimetric adsorption apparatus was developed and used to generate adsorption/desorption isotherms of TCA at 288, 293 and 298 K on two soil samples, obtained from Visalia-California and Times Beach-Missouri, with different physical/chemical characteristics. The influences of temperature and soil properties were investigated, Isosteric heats of adsorption were calculated and heat curves were established. The experimental data were correlated by well-known vapor phase isotherm models including the Polanyi Potential, the BET, and the GAB models, Equilibrium isotherms of TCA on both soils were Type II, characterizing vapor condensation to form multilayers, and they exhibited hysteresis upon desorption, A positive correlation between the soil’s specific surface area and its sorption capacity was observed, Clay content and pore size were also dominating factors, Thermal data showed that the adsorption of TCA vapor on soil was primarily due to physical forces and both samples exhibited energetically heterogeneous surfaces. Results followed the Potential Theory satisfactorily and led to a single temperature-independent characteristic curve for each soil-TCA pair, The BET model gave an accurate data fit for up to 40% of the saturation pressure, while the GAB model provided a superior fit of the data for the entire relative pressure range. (C) 1997 Published by Elsevier Science B, V.

Keywords: Adsorption, Vapor, 1,1,1-Trichloroethane, Soil, Volatile Organic Pollutant, Organic-Compounds, Sorption, Moisture, Matter, Water

? Santharam, S.K., Erickson, L.E. and Fan, L.T. (1997), Modelling the role of surfactant and biodegradation in the remediation of aquifers with non-aqueous phase contaminants. Journal of Hazardous Materials,