Personal Research Database

Full Text: 2002\J Haz Mat94, 191.pdf

Abstract: Soils, subsoils, and aquifer materials can be modified with hydrophobic cationic surfactants to increase their sorption capabilities for organic contaminants. The objective of this study was to examine in detail the sorptive characteristics of the natural loess soil and the resultant organo-modified soils for aqueous-phase neutral organic compounds (NOCs) in an attempt to define the operative sorptive mechanisms. Under the laboratory conditions, a series of modified loess soils in this study were prepared by replacing the cations of loess soil with both cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) and anionic surfactant sodium dodethylbenzene sulfonate (SDBS). Toluene was selected as an indicator to study the sorption behavior of the NOCs in loess soils. The sorption isotherms of toluene in soil samples obtained using the batch equilibration method. The results indicated that natural loess had a poor sorption capability for NOCs, and sorption isotherms of toluene appeared likely nonlinear and fit the Freundlich equation very well. When the soils were coated with large alkyl surfactants such as HDTMA-Br, sorption isotherms correspondingly became linear and the sorptive capability was prominently dependent on the quantity of hexadecyltrimethylammonium (HDTMA) and SDBS added into the soils. The study could provide an essential basis on attenuation of organic contaminants in the subsurface environment. (C) 2002 Elsevier Science B.V. All rights reserved.

Keywords: Adsorption, Anionic Surfactant, Batch, Behavior, Bromide, Cationic Surfactant, Clay, Contaminants, Environment, Freundlich, Freundlich Equation, HDTMA, Hexadecyltrimethylammonium, Hydrophobic, Isotherms, Loess Soil, Mobility, Modified, Natural, Organic Compounds, Organic Contaminants, Organo-Modified, Organobentonites, p-nitrophenol, Partition, Peat Soil, Rights, Samples, SDBS, Soil, Soils, Sorption, Sorption Isotherms, Sorptive Characteristics, Surfactant, Surfactants, Tetrachloromethane Sorption, Toluene, Water

? Wu, J., West, L.J. and Stewart, D.I. (2002), Effect of humic substances on Cu(II) solubility in kaolin-sand soil. Journal of Hazardous Materials, 94 (3), 223-238.

Full Text: 2002\J Haz Mat94, 223.pdf

Abstract: The type and amount of organic matter present in industrially contaminated soils will influence the risk they pose. Previous studies have shown the importance of humic and fulvic acids (FAs) (important components of soil organic matter) in increasing the solubility of toxic metals but were not carried out using toxic metal levels and the pH range typical of industrially contaminated soils. This study investigated the influence of three humic substances (HSs: humates, fulvates and humins) on the solubility of copper(II) ions in kaolinitic soil spiked with Cu at levels representative of industrially contaminated soil. Humates, fulvates and humin were extracted from Irish moss peat, and controlled pH batch leaching tests were conducted on an artificial kaolin-sand soil that was spiked with each. Further leaching tests were conducted on soil spiked with each HS and copper nitrate. Dissolved organic contents were determined by titration and total and free aqueous copper concentrations in the leachate were measured using AAS and ion selective electrode (ISE) potentiometry respectively (dissolved complexed copper levels were determined by difference). It was found that humates and fulvates are partially sorbed by the soil, probably by chemisorption on positively charged gibbsite (Al-hydroxide) sites in the kaolinite. The addition of 340 mg/kg Cu(II) ions did not significantly affect the amount of humate or fulvate sorbed. Dissolved humates and fulvates form soluble complexes with copper over the pH range 3-11. However, in the presence of kaolinite, soluble copper humates and fulvates are unable to compete with the kaolinite for Cu ions at pH 6-7. Above pH 8, humate and fulvate complexes are the only forms of dissolved Cu. Humin is largely insoluble and has little effect on Cu mobility between pH 2 and 12. The implication of this study is that measurement of total soil organic content and water leaching tests should be a standard part of contaminated site investigation. (C) 2002 Elsevier Science B.V. All rights reserved.

Keywords: AA, AAS, Acid, Adsorption, Affect, Batch, Chemisorption, Contaminated Soil, Copper, Copper(II), Copper(II) Ions, Cu, Cu(II), Cu(II) Ions, Difference, Fulvate, Gibbsite, Humate, Humic Substances, Humin, Influence, Ions, Kaolinite, Leachate, Leaching, Leaching Tests, Measurement, Metal, Metals, Mobility, Nitrate, Organic Matter, Peat, pH, Presence, Rights, Risk, Soil, Soil Organic Matter, Sorption, Toxic Metals, Water

? Yang, C.L. and Dluhy, R. (2002), Electrochemical generation of aluminum sorbent for fluoride adsorption. Journal of Hazardous Materials, 94 (3), 239-252.

Full Text: 2002\J Haz Mat94, 239.pdf

Abstract: Aluminum sorbent (Al-sorbent) was produced in a parallel-plate electrochemical reactor by anodic dissolution of aluminum electrodes in a dilute sodium chloride (NaCl) aqueous solution. The NaCl in the solution effectively reduced the power consumption and promoted the sorbent generation by depasivating the aluminum-water electrochemical system. The freshly generated Al-sorbent was able to reduce fluoride concentration from 16 to 2 mg/l in 2 min. The final concentration was further reduced to 0.1 mg/l by partial neutralization of the mixture to pH 6.3. The sorbent generation and fluoride adsorption was integrated into a single electrochemical reactor. The system was able to reduce the fluoride concentration from 16 to 6 mg/l in 2 min of treatment and to about 2 mg/l in 4 min. The effluent from the electrochemical system needs pH adjustment to bring the fluoride concentration down to less than 1 mg/l. (C) 2002 Elsevier Science B.V. All rights reserved.

Keywords: Adjustment, Adsorption, Aluminum, Aluminum Sorbent, Anodic Dissolution, Aqueous Solution, Consumption, Dissolution, Effluent, Electrochemical Reactor, Exchange, Fluoride, Fluoride Adsorption, Fluoride Removal, Generation, Hydrolysis, Hydroxide, Kinetics, Needs, pH, Power, Removal, Rights, Sodium Chloride, Sorbent, Speciation, Treatment, Waste-Waters

? Piña, J., Merino, J., Errazu, A.F. and Bucalá, V. (2002), Thermal treatment of soils contaminated with gas oil: influence of soil composition and treatment temperature. Journal of Hazardous Materials, 94 (3), 273-290.

Full Text: 2002\J Haz Mat94, 273.pdf

Abstract: Samples of two soils containing different organic matter contents, neat or contaminated with gas oil (diesel fuel oil) at 2.5 wt.% were heated from room temperature to different final temperatures (200-900°C). The experiments, performed in an anaerobic media, simulate conditions pertinent to ex situ thermal desorptive and thermal destructive treatments. The products generated during the heating were collected and light gases were analyzed by gas chromatography. The results indicate that the chemical composition of the soil is a key factor since it strongly influences the quantity and composition of the off-gases. According to the liquid and light gas yields, the gas oil does not affect appreciably the generation of pyrolysis products of the own soil constituents and the gas oil does not suffer significant chemical transformations even at high operating temperatures (e.g. 900°C). With surface areas of 16 000 cm²/g (Soil A) and 85 000 cm²/g (Soil B) based on the monolayer adsorbed model, 4 and 20%, respectively, of the original gas oil can be adsorbed. These values are in good agreement with experimental data. Even for high temperatures, the employed thermal treatment is capable to practically remove the gas oil from the soil bed without changing appreciably the original chemical composition of the contaminant, (C) 2002 Elsevier Science B.V. All rights reserved.

Keywords: Adsorption, Affect, Agreement, Anaerobic, Analytical Pyrolysis, Chemical Characterization, Composition, Decontamination, Desorption Technologies, Experiments, Fuel, Fuel Oil, Gas Chromatography, Gas Oil Contamination, Generation, Humic Substances, Hydrocarbons, Incineration, Influence, Influences, Ionization Mass-Spectrometry, Key, Media, Monolayer, Oil, Organic Matter, Organic-Compounds, Pyrolysis, Rights, Soil, Soil Cleanup, Soils, Surface, Temperature, Thermal Desorption, Thermal Destruction, Thermal Treatment, Treatment, Values

Mathialagan, T. and Viraraghavan, T. (2002), Adsorption of cadmium from aqueous solutions by perlite. Journal of Hazardous Materials, 94 (3), 291-303.

Full Text: J\J Haz Mat94, 291.pdf

Abstract: The present study examined the use of perlite for the removal of cadmium from aqueous solutions. The effects of pH and contact time on the adsorption process were examined. The optimum pH for adsorptionwas found to be 6.0. Residual cadmium concentration reached equilibrium in 6 h and the rate of cadmium adsorption by perlitewas rapid in the first hour of the reaction time. Ho’s pseudo-second order model best described the kinetics of the reaction. Batch adsorption experiments conducted at room temperature (22±1°C) showed that the adsorption pattern followed the Freundlich isotherm model. The maximum removal of cadmium obtained from batch studies was 55%. Thomas model was used to describe the adsorption data from column studies. The results generally showed that perlite could be considered as a potential adsorbent for cadmium removal from aqueous solutions. © 2002 Elsevier Science B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption Kinetics Isotherms, Adsorption Process, Aqueous Solutions, Batch, Batch Adsorption, Batch Studies, Cadmium, Cadmium Adsorption, Column, Column Studies, Concentration, Contact, Data, Effects, Equilibrium, Experiments, First, Fly-Ash, Freundlich, Freundlich Isotherm, Freundlich Isotherm Model, Isotherm, Isotherm Model, Kinetics, Model, Oxide-Water Interface, Pattern, Peat, Perlite, pH, Potential, Process, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Removal, Rights, Room Temperature, Solutions, Temperature, Thomas Model

Chakir, A., Bessiere, J., El Kacemi, K. and Marouf, B. (2002), A comparative study of the removal of trivalent chromium from aqueous solutions by bentonite and expanded perlite. Journal of Hazardous Materials, 95 (1-2), 29-46.

Full Text: J\J Haz Mat95, 29.pdf

Abstract: Local bentonite and expanded perlite (Morocco) have been characterised and used for the removal of trivalent chromium from aqueous solutions. The kinetic study had showed that the uptake of Cr(III) by bentonite is very rapid compared to expanded perlite. To calculate the sorption capacities of the two sorbents, at different pH, the experimental data points have been fitted to the Freundlich and Langmuir models, respectively, for bentonite and expanded perlite. For both sorbents the sorption capacity increases with increasing the pH of the suspensions. The removal efficiency has been calculated for both sorbents resulting that bentonite (96% of Cr(III) was removed) is more effective in removing trivalent chromium from aqueous solution than expanded perlite (40% of Cr(III) was removed). In the absence of Cr(III) ions, both bentonite and expanded perlite samples yield negative zeta potential in the pH range of 2–11. The changes of expanded perlite charge, from negative to positive, observed after contact with trivalent Chromium(III) solutions was related to Cr(III) sorption on the surface of the solid. Thus, it was concluded that surface complexation plays an important role in the sorption of Cr(III) species on expanded perlite. In the case of bentonite, cation-exchange is the predominate mechanism for sorption of trivalent chromium ions, wherefore no net changes of zeta potential was observed after Cr(III) sorption. X-ray photoelectron spectroscopy measurements, at different pH values, were also made to corroborate the zeta potential results.

Keywords: Chromium(III) Sorption, Bentonite, Expanded Perlite, Zeta Potential, X-Ray Photoelectron Spectroscopy

? Kastner, J.R., Das, K.C. and Melear, N.D. (2002), Catalytic oxidation of gaseous reduced sulfur compounds using coal fly ash. Journal of Hazardous Materials, 95 (1-2), 81-90.

Full Text: 2002\J Haz Mat95, 81.pdf

Abstract: Activated carbon has been shown to oxidize reduced sulfur compounds, but in many cases it is too costly for large-scale environmental remediation applications. Alternatively, we theorized that coal fly ash, given its high metal content and the presence of carbon could act as an inexpensive catalytic oxidizer of reduced sulfur compounds for “odor” removal. Initial results indicate that coal fly ash can catalyze the oxidization of H2S and ethanethiol, but not dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) at room temperature. In batch reactor systems, initial concentrations of 100-500 ppmv H₂S or ethanethiol were reduced to 0-2 ppmv within 1-2 and 6-8 min, respectively. This was contrary to control systems without ash in which concentrations remained constant. Diethyl disulfide was formed from ethanethiol substantiating the claim that catalytic oxidation occurred. The presence of water increased the rate of adsorption/reaction of both H₂S and ethanethiol for the room temperature reactions (23-25°C). Additionally, in a continuous flow packed bed reactor, a gaseous stream containing an inlet H₂S concentration of 400-500 ppmv was reduced to 200 ppmv at a 4.6 s residence time. The removal efficiency remained at 50% for approximately 4.6 h or 3500 reactor volumes. These results demonstrate the potential of using coal fly ash in reactors for removal of H₂S and other reduced sulfur compounds. (C) 2002 Elsevier Science B.V. All rights reserved.

Keywords: Activated Carbon, Activated Carbon-Fiber, Air, Applications, Batch, Carbon, Catalytic Oxidation, Coal Fly Ash, Control, Dmds, Dms, Efficiency, Environmental, Fly Ash, H₂S, Hydrogen-Sulfide, Mechanism, Metal, Odor, Oxidation, Packed Bed, Packed Bed Reactor, Packed-Bed, Presence, Reactor, Remediation, Removal, Removal Efficiency, Rights, Sulfur, Systems, Temperature, Water

Shukla, A., Zhang, Y.H., Dubey, P., Margrave, J.L. and Shukla, S.S. (2002), The role of sawdust in the removal of unwanted materials from water. Journal of Hazardous Materials, 95 (1-2), 137-152.

Full Text: J\J Haz Mat95, 137.pdf

Abstract: Sawdust, a relatively abundant and inexpensive material is currently being investigated as an adsorbent to remove contaminants from water. Chemical substances including dyes, oil, toxic salts and heavy metals can be removed very effectively with the organic material. This article presents a brief review on the role of sawdust in the removal of contaminants. Studies on the adsorption of various pollutants by different sawdust materials are reviewed and the adsorption mechanism, influencing factors, favorable conditions, etc. discussed in this paper. Some valuable guidelines can be drawn for either scientific research or industrial design.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption, Adsorption Mechanism, Aqueous-Solutions, Contaminants, Copper, Design, Dyes, Elsevier Science, Equilibrium, Factors, Guidelines, Heavy Metals, Heavy-Metals, Industrial, Influencing Factors, Kinetics, Mechanism, Metals, NOV, Organic, Pollutants, Polyacrylamide-Grafted Sawdust, Removal, Research, Review, Role, Salts, Sawdust, Science, Scientific Research, Sorbent, Toxic, Waste Treatment, Wastes, Water

Bayat, B. (2002), Comparative study of adsorption properties of Turkish fly ashes: I. The case of nickel(II), copper(II) and zinc(II). Journal of Hazardous Materials, 95 (3), 251-273.

Full Text: J\J Haz Mat95, 251.pdf

Abstract: The objective of this study was to compare two different Turkish fly ashes (Afsin-Elbistan and Seyitomer) for their ability to remove nickel [Ni(II)], copper [Cu(II)] and zinc [Zn(II)] from an aqueous solution. The effect of contact time, pH, initial metal concentration and fly ash origin on the adsorption process at 20±2 °C were studied. Batch kinetic studies showed that an equilibrium time of 2 h was required for the adsorption of Ni(II), Cu(II) and Zn(II) on both the fly ashes. The maximum metal removal was found to be dependent on solution pH (7.0–8.0 for Ni(II), 5.0–6.0 for Cu(II) and 6.0–7.0 for Zn(II)) for each type of fly ash. With an increase in the concentrations of these metals, the adsorption of Ni(II) and Zn(II) increased while the Cu(II) adsorption decreased on both the fly ashes. Adsorption densities for the metal ions were Zn(II)>Cu(II)>Ni(II) for both the fly ashes. The effectiveness of fly ash as an adsorbent improved with increasing calcium (CaO) content. Adsorption data in the range of pH values (3.0–8.0) using Ni(II) and Cu(II) concentrations of 25±2 mg/l and Zn(II) concentration of 30±2 mg/l in solution were correlated using the linear forms of the Langmuir and Freundlich equations. The adsorption data were better fitted to the Langmuir isotherm since the correlation coefficients for the Langmuir isotherm were higher than that for the Freundlich isotherm. The fly ash with high calcium content (Afsin-Elbistan) was found to be a metal adsorbent as effective as activated carbon and, therefore, there are good prospects for the adsorptions of these metals on fly ash with high calcium content in practical applications in Turkey.

Keywords: Ability, Activated Carbon, Adsorbent, Adsorption, Adsorption Process, Adsorption Properties, Aqueous Solution, Aqueous-Solutions, Calcium, Carbon, Concentration, Contact, Content, Copper, Copper(II), Correlation, Cu(II), Cu²⁺, Data, Effectiveness, Elsevier Science, Equilibrium, Equilibrium Time, Fly Ash, Fly-Ash, Forms, Freundlich, Freundlich Isotherm, Freundlich’s Model, Heavy-Metals, Ions, Isotherm, Kinetic, Kinetic Studies, Langmuir, Langmuir Isotherm, Langmuir’s Model, Metal, Metal Ions, Metal Removal, Metal Sorption, Metals, Ni(II), Nickel, Nickel(II), Objective, Origin, pH, Process, Removal, Rights, Science, Solution, Time, Turkey, Turkish, Values, Water, Zinc, Zinc(II), Zn(II), Zn²⁺

Bayat, B. (2002), Comparative study of adsorption properties of Turkish fly ashes: II. The case of chromium(VI) and cadmium(II). Journal of Hazardous Materials, 95 (3), 275-290.

Full Text: J\J Haz Mat95, 275.pdf

Abstract: The purpose of the study described in this paper was to compare the removal of Cr(VI) and Cd(II) from an aqueous solution using two different Turkish fly ashes; Afsin-Elbistan and Seyitomer as adsorbents. The influence of four parameters (contact time, solution pH, initial metal concentration in solution and ash quality) on the removal at 20±2°C was studied. Fly ashes were found to have a higher adsorption capacity for the adsorption of Cd(II) as compared to Cr(VI) and both Cr(VI) and Cd(II) required an equilibrium time of 2 h. The adsorption of Cr(VI) was higher at pH 4.0 for Afsin-Elbistan fly ash (25.46%) and pH 3.0 for Seyitomer fly ash (30.91%) while Cd(II) was adsorbed to a greater extent (98.43% for Afsin-Elbistan fly ash and 65.24% for Seyitomer fly ash) at pH 7.0. The adsorption of Cd(II) increased with an increase in the concentrations of these metals in solution while Cr(VI) adsorption decreased by both fly ashes. The lime (crystalline CaO) content in fly ash seemed to be a significant factor in influencing Cr(VI) and Cd(II) ions removal. The linear forms of the Langmuir and Freundlich equations were utilised for experiments with metal concentrations of 55±2 mg/l for Cr(VI) and 6±0.2 mg/l for Cd(II) as functions of solution pH (3.0–8.0). The adsorption of Cr(VI) on both fly ashes was not described by both the Langmuir and Freundlich isotherms while Cd(II) adsorption on both fly ashes satisfied only the Langmuir isotherm model. The adsorption capacities of both fly ashes were nearly three times less than that of activated carbon for the removal of Cr(VI) while Afsin-Elbistan fly ash with high-calcium content was as effective as activated carbon for the removal of Cd(II). Therefore, there are possibilities for use the adsorption of Cd(II) ions onto fly ash with high-calcium content in practical applications in Turkey.

Keywords: Adsorption, Chromium, Cadmium, Fly Ash, Langmuir’s Model, Freundlich’s Model

? Yeh, C.K.J., Wu, H.M. and Chen, T.C. (2003), Chemical oxidation of chlorinated non-aqueous phase liquid by hydrogen peroxide in natural sand systems. Journal of Hazardous Materials, 96 (1), 29-51.

Full Text: 2003\J Haz Mat96, 29.pdf

Abstract: This study explored the Fenton-like oxidation of trichloroethylene (TCE) existing as dense non-aqueous phase liquid (DNAPL) in natural silica sand (iron = 0.04 g/kg) and the sand from an aquifer (iron = 2.01 g/kg). Glass bead containing no iron mineral was used as the control. Batch oxidation experiments were conducted to assess interactions between oxidant and TCE DNAPL. Column experiments were performed to evaluate dynamics of TCE and H₂O₂ during oxidation. The pH was not altered. In the batch system, a single application of 3% H₂O₂ to the aquifer sand oxidized 40% of the added TCE DNAPL in 1 h, which was four times of that by dissolution with the gas purge procedure. This demonstrated the ability of mineral-catalyzed Fenton-like reaction to directly oxidize TCE in non-aqueous liquid. In the column experiments, after passing 7 pore volumes (PVs) of 1.5 and 3% H₂O₂ solution, the residual TCE in aquifer sand column was 12.0 and 2.6% of the initial added, respectively. On the other hand, 28.4% of the added TCE still remained in the silica sand column by 7 PVs of 3% H₂O₂. The distribution of TCE in column and effluent indicated the occurring of direct oxidation of TCE DNAPL and the increased solubilization, which probably due to size reduction of DNAPL droplets, followed by water-phased TCE oxidation. (C) 2002 Elsevier Science B.V All rights reserved.

Keywords: Ability, Batch, Chemical Oxidation, Column, Column Experiments, Contaminated Soils, Control, Degradation, Distribution, Dnapl, Dynamics, Effluent, Experiments, Fenton Like, Fenton-Like, Fentons Reagent, Groundwater Remediation, H₂O₂, Hydrogen Peroxide, Interactions, Iron, Natural, Oxidation, pH, Reduction, Remediation, Rights, Sand, Silica, Solubilization, Sorption, Systems, TCE, Trichloroethylene

? Moutsatsou, A., Chalarakis, E. and Zarangas, G. (2003), Influence of raw materials and distillation equipment on-the heavy metal content of waste from an alcoholic anis-type beverage. Journal of Hazardous Materials, 96 (1), 53-64.

Full Text: 2003\J Haz Mat96, 53.pdf

Abstract: This study focused on the heavy metal content waste resulting from the production of an anis-type beverage. Although natural ingredients were used in the production process, the waste contains heavy metals and is considered hazardous. Several metals were found in the waste (Fe, Cu, Ni, Zn, Cr and Cd), with concentrations of Fe to 157.5, Cu to 82.5, Zn to 31 and Ni to 8.5 mg/l. To collect information on the source of these metals, the residues of the herbs used for flavoring were examined for processes employing metallic and non-metallic pot stills. Herbs distillation residues were found to contain metals in non-metallic stills, e.g. aniseed residues from glass stills contained Cu up to 1.02 and Ni up to 0.9 mg/l. Fennel residues contained Ni up to 1.2 and Zn up to 6.6 mg/l. The main source for the metals was the bronze pot stills. The metals were in complexed form in the solution. The existence of metals in the amorphous phase as shown by a SEM micrograph indicates forming of metal-organic complexes, also verified by HPLC. Complexation data can be used for selecting the proper wash treatment method. The formation of large molecules favors precipitation and chemi-sorption treatment methods. (C) 2002 Elsevier Science B.V All rights reserved.

Keywords: Anis-Type Beverage, Aqueous Waste, Cd, Chemisorption, Complexation, Complexes Formation In Residues, Cu, Fertilizers, Heavy Metal, Heavy Metals, Heavy-Metal, HPLC, Information, Metal, Metal-Organic Complexes, Metals, Methods, Natural, Pot Stills Corrosion, Precipitation, Process, Production, Rights, SEM, Soils, Treatment, Zn

Clark, II, C.J., Rao, P.S.C. and Annable, M.D. (2003), Degradation of perchloroethylene in cosolvent solutions by zero-valent iron. Journal of Hazardous Materials,