Personal Research Database

Full Text: 2006\J Haz Mat129, 80.pdf

Abstract: In this paper, the technical applicability and treatment performance of physico-chemical techniques (individual and/or combined) for landfill leachate are reviewed. A particular focus is given to coagulation-flocculation, chemical precipitation, ammonium stripping, membrane filtration and adsorption. The advantages and limitations of various techniques are evaluated. Their operating conditions such as pH, dose required, characteristics of leachate in terms of chemical oxygen demand (COD) and NH3-N concentration and treatment efficiency are compared. It is evident from the survey of 118 papers (1983-2005) that none of the individual physico-chemical techniques is universally applicable or highly effective for the removal of recalcitrant compounds from stabilized leachate. Among the treatments reviewed in this article, adsorption, membrane filtration and chemical precipitation are the most frequently applied and studied worldwide. Both activated carbon adsorption and nanofiltration are effective for over 95% COD removal with COD concentrations ranging from 5690 to 17,000mg/L. About 98% removal of NH3-N with an initial concentration ranging from 3260 to 5618 mg/L has been achieved using struvite precipitation. A combination of physico-chemical and biological treatments has demonstrated its effectiveness for the treatment of stabilized leachate. Almost complete removal of COD and NH3-N has been accomplished by a combination of reverse osmosis (RO) and an upflow anaerobic sludge blanket (UASB) with an initial COD concentration of 35,000 mg/L and NH3-N concentration of 1600 mg/L and/or RO and activated sludge with an initial COD concentration of 6440 mg/L and NH3-N concentration of 1153 mg/L. It is important to note that the selection of the most suitable treatment method for landfill leachate depends on the characteristics of landfill leachate, technical applicability and constraints, effluent discharge alternatives, cost-effectiveness, regulatory requirements and environmental impact. (c) 2005 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activated Carbon Adsorption, Activated Sludge, Adsorption, Alternatives, Ammoniacal-Nitrogen, Ammonium, Anaerobic Sludge, Biological, Biological Treatment, Carbon, Characteristics, Chemical, Chemical Oxygen Demand, Chemical Precipitation, Coagulation-Flocculation, Cod, Combined Treatment, Concentration, Contaminants, Cost Effectiveness, Cost-Effectiveness, Demand, Discharge, Effectiveness, Efficiency, Environmental, Environmental Impact, Fed-Batch Operation, Filtration, Heavy-Metal Removal, Impact, Landfill, Landfill Leachate, Landfill Leachate Management, Leachate, Membrane, Membrane Filtration, Municipal Solid Waste (MSW), Nanofiltration, NH₃-N, Non-Biodegradable Compounds, Operating Conditions, Organic-Matter, Osmosis, Oxygen, Papers, Performance, pH, Powdered Activated Carbon, Precipitation, Recalcitrant Compounds, Removal, Reverse Osmosis, Reverse-Osmosis, Rights, Sludge, Stabilized Leachates, Stripping, Survey, Techniques, Treatment, Waste-Water Treatment

? Daneshvar, N., Oladegaragoze, A. and Djafarzadeh, N. (2006), Decolorization of basic dye solutions by electrocoagulation: An investigation of the effect of operational parameters. Journal of Hazardous Materials, 129 (1-3), 116-122.

Full Text: 2006\J Haz Mat129, 116.pdf

Abstract: Electrocoagulation (EC) is one of the most effective techniques to remove color and organic pollutants from wastewater, which reduces the sludge generation. In this paper, electrocoagulation has been used for the removal of color from solutions containing C.I. Basic Red 46 (BR46) and C.I. Basic Blue 3 (BB3). These dyes are used in the wool and blanket factories for fiber dyeing. The effect of operational parameters such as current density, initial pH of the solution, time of electrolysis, initial dye concentration and solution conductivity were studied in an attempt to reach higher removal efficiency. The findings in this study shows that an increase in the current density up to 60-80 A m^-2 enhanced the color removal efficiency, the electrolysis time was 5 min and the range of pH was determined between 5.5 and 8.5 for two mentioned dye solutions. It was found that for, the initial concentration of dye in solutions should not be higher than 80 mg l^-1 in order to achieve a high color removal percentage. The optimum conductivity was found to be 8 mS cm^-1, which was adjusted using proper amount of NaCl with the dye concentration of 50 mg l^-1. Electrical energy consumption in the above conditions for the decolorization of the dye solutions containing BR46 and BB 3 were 4.70 kWh (kg(dye) (removed)) ^-1 and 7.57 kWh (kg(dye) (removed))^-1, respectively. Also, during the EC process under the optimized conditions, the COD decreased by more than 75% and 99% in dye solutions containing BB3 and BR46, respectively. (c) 2005 Elsevier B.V. All rights reserved.

Keywords: Electrocoagulation, Basic Dye, Decolorization, COD Reduction, Dyeing Wastewater, Waste-Water, Textile Wastewaters, Aluminum Electrodes, Coagulation, Degradation, Cr(VI), Iron

? Rao, M.M., Ramesh, A., Rao, G.P.C. and Seshaiah, K. (2006), Removal of copper and cadmium from the aqueous solutions by activated carbon derived from Ceiba pentandra hulls. Journal of Hazardous Materials, 129 (1-3), 123-129.

Full Text: 2006\J Haz Mat129, 123.pdf

Abstract: Activated carbon prepared from Ceiba pentandra hulls, an agricultural solid waste by-product, for the removal of copper and cadmium from aqueous solutions has been studied. Parameters such as equilibrium time, effect of pH and adsorbent dose on removal were studied. The adsorbent exhibited good sorption potential for copper and cadmium at pH 6.0. C=O and S=O functional groups present on the carbon surface were the adsorption sites to remove metal ions from solution. The experimental data was analysed by both Freundlich and Langmuir isotherm models. The maximum adsorption capacity of copper and cadmium was calculated from Langmuir isotherm and found to be 20.8 and 19.5 mg/g, respectively. The sorption kinetics of the copper and cadmium have been analysed by Lagergren pseudo-first-order and pseudo-second-order kinetic models. The desorption studies were carried out using dilute hydrochloric acid solution and the effect of HCl concentration on desorption was also studied. Maximum desorption of 90% for copper and 88% for cadmium occurred with 0.2 M HCl.

Keywords: Acid, Activated Carbon, Adsorbent, Adsorbent Dose, Adsorption, Adsorption, Adsorption Capacity, Agricultural, Agricultural By-Products, Agricultural Solid Waste, Aqueous Solutions, Cadmium, Capacity, Carbon, Cd(II), Ceiba Pentandra Hulls, Concentration, Copper, Data, Desorption, Desorption Studies, Effect of pH, Equilibrium, Equilibrium Time, Experimental, Freundlich, Functional Groups, Groups, Ions, Isotherm, Isotherm Models, Kinetic, Kinetic Models, Kinetics, Lagergren, Langmuir, Langmuir Isotherm, Metal, Metal Ions, Metal-Ions, Models, pH, Pith, Potential, Pseudo First Order, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-First-Order, Pseudo-Second-Order, Removal, Rights, Sludge, Solid Waste, Solution, Solutions, Sorption, Sorption Kinetics, Sorption Potential, Surface, Time, Waste, Waste-Water, Zinc

? Özkaya, B. (2006), Adsorption and desorption of phenol on activated carbon and a comparison of isotherm models. Journal of Hazardous Materials, 129 (1-3), 158-163.

Full Text: 2006\J Haz Mat129, 158.pdf

Abstract: In this study, the potential of activated carbon for phenol adsorption from aqueous solution was studied. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, initial concentration, and desorption characteristics of activated carbon. The equilibrium data in aqueous solutions was represented by the isotherm models. Desorption studies to recover the adsorbed phenol from activated carbon performed with NaOH solution. It is necessary to propose a suitable model to gain a better understanding on the mechanism of phenol desorption. For this purpose, pore diffusion and first-order kinetic models were compared. The diffusivity rate (D/r²) and first-order desorption rate (k_D) constants were determined as 6.77×10⁻⁴ and 3.924×10⁻⁴ s⁻¹, respectively. The two- and three-parameter in the adopted adsorption isotherm models were obtained using a non-linear regression with the help of MATLAB^® package program. It was determined that best-fitted adsorption isotherm models were determined to be in the order: Langmiur > Toth > Redlich–Peterson > Freundlich isotherms.

Keywords: Activated Carbon, Adsorption, Desorption, Kinetic, Phenol

? Ho, Y.S. and Ofomaja, A.E. (2006), Pseudo-second-order model for lead ion sorption from aqueous solutions onto palm kernel fiber. Journal of Hazardous Materials, 129 (1-3), 137-142.

Full Text: 2006\J Haz Mat129, 137.pdf 2005\J Haz Mat-Ho.pdf

Abstract: The sorption of lead ion onto palm kernel fiber was studied by performing batch kinetic sorption experiments. The batch sorption model, based on a pseudo-second-order mechanism, was applied to predict the rate constant of sorption, the equilibrium capacity and the initial sorption rate with the effects of the initial solution pH and fiber dose. Equilibrium concentrations were evaluated with the equilibrium capacity obtained from the pseudo-second-order rate equation. In addition, pseudo-isotherms were also obtained by changing fiber doses using the equilibrium concentration and equilibrium capacity obtained based on the pseudo-second-order constants.

Keywords: Adsorption, Aqueous Solutions, Batch, Biosorption, Capacity, Concentration, Equilibrium, Experiments, Kinetic, Kinetic Sorption, Lead, Mechanism, Model, Palm Kernel Fiber, pH, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Pseudo-Second-Order Rate, Rate Constant, Solution, Solutions, Sorption

? Kumar, K.V. and Sivanesan, S. (2006), Isotherm parameters for basic dyes onto activated carbon: Comparison of linear and non-linear method. Journal of Hazardous Materials, 129 (1-3), 147-150.

Full Text: 2006\J Haz Mat129, 147.pdf

Abstract: Equilibrium sorption experiments were carried out at 305 K with four different basic dyes basic red 9 (BR9), basic violet 3 (BV3), basic brown 1 (BB1) and basic violet 10 (BV10) onto activated carbon. The isotherm parameters were estimated linear and non-linear regression analysis. Non-linear method was found to be more appropriate method for estimating the isotherm parameters. The sorption capacity of activated carbon to uptake cationic dye ions in the increasing order was given by: BR9 (131 mg/g)

Keywords: Adsorption, Isotherms, Least Squares Regression, Coefficient of Determination, Linear Method, Non-Linear Method

? Hsueh, C.L., Huang, Y.H. and Chen, C.Y. (2006), Novel activated alumina-supported iron oxide-composite as a heterogeneous catalyst for photooxidative degradation of reactive black 5. Journal of Hazardous Materials, 129 (1-3), 228-233.

Full Text: 2006\J Haz Mat129, 228.pdf

Abstract: A novel activated alumina-supported iron oxide-composite (denoted as FeAA-500) was prepared by so-called fluidized-bed reactor (FBR) crystallization. X-ray powder diffraction (XRD), N-2 adsorption/desorption, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to characterize the FeAA-500. The photo-catalytic activity of the FeAA-500 was evaluated in the photooxidative degradation of 0.1 mM azo-dye reactive black 5 (RB5) in the presence of H2O2 and UVA light (lambda = 365 nm) in a solution with a pH of 2.5. Complete decolorization of the model pollutant RB5 was achieved; the total organic carbon (TOC) removal ratio was 95%, and a trace amount of leached ferric ion was detected following 75 min of reaction when 2.0 g/L FeAA-500 was used as a catalyst. FeAA-500 has high photo-catalytic activity; it is therefore a promising heterogeneous photocatalysis of the degradation of organic compounds. (c) 2005 Elsevier B.V. All rights reserved.

Keywords: Activity, Azo Dye, Azo-Dye, Biodegradability, Carbon, Catalyst, Crystallization, Decolorization, Degradation, Dye Orange-II, EDX, Electron Microscopy, Energy, Energy Dispersive X-Ray, Fe-Nanocomposite, Ferric, Fluidized Bed Reactor, Fluidized-Bed Reactor, H₂O₂2, Heterogeneous, Heterogeneous Catalyst, Heterogeneous Photocatalysis, Hydrogen-Peroxide, Ion, Iron, Iron Oxide, Light, Microscopy, Mineralization, Model, Organic, Organic Carbon, Organic Compounds, Oxidation, pH, Photo-Fenton Reactions, Photocatalysis, Photocatalytic Activity, Pollutant, Reaction, Reactive Black 5, Reactor, Removal, Scanning Electron Microscopy, SEM, Spectroscopy, TOC, Total Organic Carbon, UVA, Water, XRD

? Özcan, A., Öncü, E.M. and Özcan, A.S. (2006), Adsorption of Acid Blue 193 from aqueous solutions onto DEDMA-sepiolite. Journal of Hazardous Materials, 129 (1-3), 244-252.

Full Text: 2006\J Haz Mat129, 244.pdf

Abstract: The adsorption of Acid Blue 193 (AB193) onto dodecylethyldimethylammonium (DEDMA)-sepiolite was investigated in aqueous solution in a batch system with respect to contact time, pH and temperature. The surface modification of DEDMA-sepiolite was examined by the FT-IR technique. The pseudo-first-order, pseudo-second-order kinetic models and the intraparticle diffusion model were used to describe the kinetic data and the rate constants were evaluated. The experimental data fitted very well with the pseudo-second-order kinetic model and also followed the simple external diffusion model up to initial 10 min and then by intraparticle diffusion model up to 75 min, whereas diffusion is not only the rate-controlling step. The adsorption capacities of natural sepiolite and DEDMA-sepiolite at pH 1.5 and 20 °C were (1.19 and 2.57)×10⁻⁴ mol g⁻¹, respectively. The above results indicate that DEDMA-sepiolite has around two times higher adsorption capacity than natural sepiolite. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and the isotherm constants were also determined. The Freundlich model agrees with experimental data well. The activation energy, change of Gibbs free energy, enthalpy and entropy of adsorption were also evaluated for the adsorption of AB193 onto DEDMA-sepiolite.

Keywords: Acid, Acid Blue, Acid Dye, Acid Dyes, Activated Carbon, Activation, Activation Energy, Adsorption, Adsorption Capacity, Aqueous, Aqueous Solutions, Basic-Dyes, Batch System, Capacity, Dedma-Sepiolite, Diffusion, Dye Adsorption, Elsevier, Entropy, Equilibrium, External Diffusion, Freundlich, FT-IR, FTIR, Intraparticle Diffusion, Isotherm, Isotherms, Kinetic, Kinetic Model, Kinetic Models, Kinetic-Models, Kinetics, Langmuir, Methylene-Blue, Model, Models, Peat, pH, Pseudo Second Order, Pseudo-Second-Order, Removal, Sepiolite, Solutions, Sorption, Surfactant, System, Temperature, Water

? Kumar, U. and Bandyopadhyay, M. (2006), Fixed bed column study for Cd(II) removal from wastewater using treated rice husk. Journal of Hazardous Materials, 129 (1-3), 253-259.

Full Text: 2006\J Haz Mat129, 253.pdf

Abstract: A fixed bed of sodium carbonate treated rice husk was used for the removal of Cd(II) from water environment. The material as adopted was found to be an efficient media for the removal of Cd(II) in continuous mode using fixed bed column. The column having a diameter of 2 cm, with different bed depths such as 10, 20 and 30 cm could treat 2.96, 5.70 and 8.55 l of Cd(II) bearing wastewater with Cd(II) concentration 10 mg/l and flow rate 9.5 ml/min. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. was calculated. Effect of flow rate and initial concentration was studied. Theoretical breakthrough curve was drawn from the batch isotherm data and it was compared with experimental breakthrough curve. An amount of 0.01 mol/l HCl solution was used for desorption of adsorption column. Column regeneration and reuse studies were conducted for two cycles of adsorption–desorption.

Keywords: Cadmium, Sodium Carbonate Treated Rice Husk (NCRH), Adsorption, Column Study, Breakthrough Curve

? Ören, A.H. and Kaya, A. (2006), Factors affecting adsorption characteristics of Zn²⁺ on two natural zeolites. Journal of Hazardous Materials, 131 (1-3), 59-65.

Full Text: 2006\J Haz Mat131, 59.pdf

Abstract: Mining-related and industrial wastes are primary sources of heavy metal contamination in soils and groundwater. The limitation of such waste in drinking water needs to meet government requirements in order to safeguard human health and environment. Zinc, one of the most preponderant pollutants, is difficult to remove from wastewater rather than other heavy metals (i.e. lead, copper and cadmium). This paper investigates Zn²⁺ adsorption characteristics of two natural zeolites found in the regions of Gordes and Bigadic, in western Turkey. The results show that the Zn²⁺ adsorption behavior of both zeolites is highly dependent on the pH. Adsorption dependence on lower pH values (pH < 4) is explained by the dissolution of crystal structure and the competition of the zinc ions with the H⁺. Between pH 4 and 6, the basic mechanism is the ion exchange process. The results also showed that decrease in grain size does not increase the adsorption capacity of zeolite from Gordes, yet it increases that of zeolite from Bigadic about 23%. The results also reveal that an increase in the initial concentration of Zn²⁺ in the system causes an increase in the adsorption capacity to a degree, then it becomes more constant at higher concentrations. With this, the removal efficiency of Gordes zeolite is two times higher than that of Bigadic zeolite. Results show that an increase in slurry concentration results in a lower uptake of Zn²⁺. In the final part of the paper, we compared the experimental data with the Langmuir and Freundlich isotherms. The results show that there is a good fit between the experimental data and empirical isotherms.

Keywords: Zinc, Zeolite, Ion Exchange, Heavy Metal, Adsorption, pH, Slurry Concentration, Metal Ion Concentration

? Karagunduz, A., Kaya, Y., Keskinler, B. and Oncel, S. (2006), Influence of surfactant entrapment to dried alginate beads on sorption and removal of Cu²⁺ ions. Journal of Hazardous Materials, 131 (1-3), 79-83.

Full Text: 2006\J Haz Mat131, 79.pdf

Abstract: The removal of heavy metals has been investigated widely in recent years due to their potential health risk to human beings. In this study, the removals of copper from aqueous phase by alginate and SDBS entrapped alginate was investigated. First, a series of equilibrium sorption experiments were conducted at different initial pH values. Both equilibrium copper concentration and final pH values were observed. Then, a series of kinetic experiments were conducted and a second order rate relationship was fit to the experimental data. Equilibrium sorption experiments showed that the sorption of Cu⁺² ions by 2% of SDBS entrapped alginate beads were greater than the plain and 0.5% of SDBS entrapped alginate beads. More H⁺ ion exchange occurred with the 2% of SDBS entrapped alginate beads, which was attributed to the increased number of the exchange sites on the alginate due to the sorption of surfactant to the beads. Kinetic sorption experiments showed that the equilibrium was reached faster for 2% of SDBS entrapped alginate beads. Results were successfully represented using second order kinetic model. Both equilibrium and kinetic experiments showed that the sorption of Cu⁺² ions increased as the pH of the aqueous solution increased.

Keywords: Alginate, Surfactant, SDBS, Sorption, Sorption Kinetics, Metal Removal

? Entezari, M.H., Ghows, N. and Chamsaz, M. (2006), Ultrasound facilitates and improves removal of Cd(II) from aqueous solution by the discarded tire rubber. Journal of Hazardous Materials, 131 (1-3), 84-89.

Full Text: 2006\J Haz Mat131, 84.pdf

Abstract: Some of the heavy metal ions such as cadmium are toxic and represent as hazardous pollutants due to their persistence in the environment. In this study the ground discarded tire rubber was used for the sorption of cadmium from aqueous solution. The batch sorption tests were conducted to investigate the sorption of Cd(II) by discarded tire rubber in the presence and absence of ultrasound. To assess the capability of sorbent, research parameters such as ultrasonic waves, solution temperature, particle size of ground tire and others were investigated. The experimental data were fitted in Langmuir model better than Freundlich one. Therefore, the former model was applied to the sorption equilibrium in order to determine the maximum metal sorption capacity in the presence and absence of ultrasound. The Langmuir constants were also obtained from the isotherms under different conditions. In the presence of ultrasound the tire rubber was a more efficient sorbent for this pollutant than its absence. According to the results, the internal porous and film diffusions were both effective in the sorption process. The porous and film diffusion coefficients of the ground tire rubber were, respectively, about 1.8 and 2.7 times more in the presence of ultrasound than its absence. The effect of ultrasound on the sorption process could be explained by the thermal and non-thermal properties of ultrasonic field.

Keywords: Ultrasound, Discarded tire Rubber, Cadmium(II), Sorption, Langmuir Model

? Sun, S.L. and Wang, A.Q. (2006), Adsorption kinetics of Cu(II) ions using N,O-carboxymethyl-chitosan. Journal of Hazardous Materials, 131 (1-3), 103-111.

Full Text: 2006\J Haz Mat131, 103.pdf

Abstract: A series of N,O-carboxymethyl-chitosan (N,O-CMC) with different degree of substitution (DS) were prepared by using chitosan (CTS) and monochloroacetic acid under various conditions. The adsorption properties of N,O-CMC were evaluated. The results revealed that N,O-CMC is suitable for adsorbent to removal Cu(II) ion. The parameters for the adsorption of Cu(II) ions by N,O-CMC were also determined. It was shown that the samples of N,O-CMC had given good correlation with Langmuir’s isotherm model and that the adsorption kinetics of Cu(II) could be best described by the pseudo-second-order model. It was also observed that the adsorption capacity seemed to be dependent on pH value in solution, the DS of samples and ionic strength. Furthermore, the maximum adsorption capacity of the monolayer was 162.5 mg of Cu(II) per gram of polymer with DS of 0.96. FTIR and X-ray photoelectron spectroscopy revealed that Cu(II) ions and N,O-CMC formed a chelate complex.

Keywords: Adsorbent, Adsorption, Adsorption Capacity, Adsorption Kinetics, Adsorption Properties, Capacity, Carboxymethyl-Chitosan, Chitosan, Copper Ions, Correlation, Ct, Cu(II), Cu(II) Ion, Cu(II) Ions, FTIR, Ionic Strength, Isotherm, Isotherm Model, Kinetics, Model, Monolayer, N,O-Carboxymethyl-Chitosan, pH, pH Value, Polymer, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Removal, Solution, Spectroscopy, Strength, Substitution, Synthesis, Value, X-Ray

? Kim, J. (2006), Assessment of ethylene removal with Pseudomonas strains. Journal of Hazardous Materials, 131 (1-3), 131-136.

Full Text: 2006\J Haz Mat131, 131.pdf

Abstract: This study investigated the biological removal of ethylene by Pseudomonas strains in a batch test and a biofilter column. In the batch test, no removal of ethylene was found in the absence of inoculated system, whereas more than 50% of the ethylene in the presence of inoculated system was degraded within 17 h, and completely removed after 25 h. The biofilter, packed with activated carbons, was capable of achieving ethylene removal efficiency as much as 100% at a residence time of 14 min and an inlet concentration of 331 mg m⁻³. Under the same conditions, carbon dioxide with a concentration of up to 1097 mg m⁻³ was produced. It was found that carbon dioxide was produced at a rate of 87 mg day⁻¹, which corresponded to a volume of 0.05 L day⁻¹. During operation with an inlet ethylene of 331 mg m⁻³, the maximum elimination capacity of the biofilter was 34 g C₂H₄ m⁻³ day⁻¹. This biological system could reduce the ethylene concentration to levels below the threshold limit for the plant hormonal response (0.01 mg m⁻³), and provide an attractive treatment technology in horticultural storage facilities.

Keywords: Activated Carbon, Biofilter, Elimination Capacity, Ethylene, Pseudomonas

? Tunali, S. and Akar, T. (2006), Zn(II) biosorption properties of Botrytis cinerea biomass. Journal of Hazardous Materials,