Personal Research Database

Full Text: 2006\J Haz Mat135, 100.pdf

Abstract: The removal of azinphosmethyl from aqueous solution onto pyrolyzed ocean peat moss (Sphagnum sp.), as a residue, from the Rhode Island coast (USA), has been investigated at different temperatures and initial concentrations. The ocean peat moss had been pyrolyzed at 600 °C in nitrogen atmosphere before the adsorption process. The kinetic data obtained from batch studies have been analyzed using pseudo-first order kinetic model. The rate constants were evaluated at different temperatures.

The thermodynamic parameters (ΔG°, ΔH°, ΔS°) for the adsorption process were calculated and the results suggest that the nature of adsorption is endothermic and the process is spontaneous and favorable. The activation energy for adsorption process was estimated, about 18.3 kJ mol⁻¹. According to this value the adsorption of azinphosmethyl onto pyrolyzed ocean peat moss is in the range of physical adsorption.

The experimental data have been modeled using Langmuir, Freundlich and Temkin isotherms. It was found that Langmuir and Freundlich isotherms give the best correlation with the experimental data.

Keywords: Adsorption, Azinphosmethyl, Freundlich Isotherm, Langmuir Isotherm, Temkin Isotherm, Peat Moss,Pyrolysis

? Lin, S.H., Hsiao, R.C. and Juang, R.S. (2006), Removal of soluble organics from water by a hybrid process of clay adsorption and membrane filtration. Journal of Hazardous Materials, 135 (1-3), 134-140.

Full Text: 2006\J Haz Mat135, 134.pdf

Abstract: The removal of phenol and o-cresol from water by a hybrid process of clay adsorption and ultrafiltration (clay-UF) was studied. Batch adsorption equilibrium experiments showed that the amount of adsorption for phenol and o-cresol decreased in the order kaolin > montmorillonite at an equilibrium pH (pH_e) of 9.1. The clay-UF experiments were performed as a function of clay dose, solution pH, and transmembrane pressure. The role of pH in clay-UF process mainly depended on the acid–base nature of phenols and clays, and the charge of UF membrane. The rejection of phenol increased with increasing pH, and had a maximum at pH_e = 8.2 with kaolin but at pH_e = 9.1 with montmorillonite. The rejection of o-cresol also increased with increasing pH, and had a maximum at pH_e = 9.2 with kaolin but at pH_e = 10.2 with montmorillonite. Such differences between solute rejections depended on the pK_a of the solutes, zeta potential of the clays, and surface charge of the membrane. The amount of soluble organics adsorbed onto the surface of membrane was negligible and the flux slightly decreased with increasing transmembrane pressure.

Keywords: Phenol, Cresol, Clay, Adsorption, Nanofiltration, Ultrafiltration

? Tunali, S., Özcan, A.S., Özcan, A. and Gedikbey, T. (2006), Kinetics and equilibrium studies for the adsorption of Acid Red 57 from aqueous solutions onto calcined-alunite. Journal of Hazardous Materials, 135 (1-3), 141-148.

Full Text: 2006\J Haz Mat135, 141.pdf

Abstract: The adsorption of Acid Red 57 (AR57) onto calcined-alunite was examined in aqueous solution in a batch system with respect to contact time, pH and temperature. The first-order, pseudo-second-order kinetic and the intraparticle diffusion models were used to describe the kinetic data and the rate constants were evaluated. The experimental data fitted very well the pseudo-second-order kinetic model and also followed the intraparticle diffusion model up to 90 min. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and the isotherm constants were also determined. The equilibrium data are successfully fitted to the Langmuir adsorption isotherm. The Langmuir isotherm constant, KL, was used to evaluate the changes of free energy, enthalpy and entropy of adsorption for the adsorption of AR57 onto calcined-alunite. The results indicate that calcined-alunite could be employed as low-cost material for the removal of acid dyes from textile effluents.

Keywords: Acid Dye, Acid Dyes, Adsorption, Adsorption Isotherm, Alunite, Aqueous Solution, Aqueous Solutions, Batch, Batch System, Changes, Data, Diffusion, Diffusion Model, Dyes, Effluents, Energy, Enthalpy, Entropy, Equilibrium, Equilibrium Studies, Experimental, First Order, Freundlich, Intraparticle Diffusion, Intraparticle Diffusion Model, Isotherm, Isotherms, Kinetic, Kinetic Model, Kinetics, Langmuir, Langmuir Adsorption Isotherm, Langmuir Isotherm, Low-Cost Material, Model, Models, pH, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Rate Constants, Removal, Solution, Solutions, Temperature, Textile Effluents

? Can, M.Y. and Yildiz, E. (2006), Phosphate removal from water by fly ash: Factorial experimental design. Journal of Hazardous Materials, 135 (1-3), 165-170.

Full Text: 2006\J Haz Mat135, 165.pdf

Abstract: The influence of three variables (phophate concentration, initial pH of solution (pH₀) and the fly ash dosage) on the removal efficiency of phosphate (% E) and equilibrium pH of solution (pH_eq) by using fly ash was studied by means of 2³ full factorial experimental designs. The parameters coded as x₁, x₂ and x₃, consecutively_, were used. The parameters were investigated at two levels (−1 and 1). The effects of these factors on dependent variables, namely, % E and pH_eq were investigated. To determine the significance of effects, the analysis of variance with 95% confidence limits was used. It was shown that % E and pH_eq obtained in this study were found to be 99.6% and 11.16, corresponding to the operating condition of 25 mg l⁻¹, 2 g l⁻¹ and 5.5 for the phosphate concentration, fly ash dosage and pH₀, respectively.

Keywords: Phosphate Removal, Fly Ash, Experimental Design, Factorial Design

? Arami, M., Limaee, N.Y., Mahmoodi, N.M. and Tabrizi, N.S. (2006), Equilibrium and kinetics studies for the adsorption of direct and acid dyes from aqueous solution by soy meal hull. Journal of Hazardous Materials, 135 (1-3), 171-179.

Full Text: 2006\J Haz Mat135, 171.pdf

Abstract: This paper deals with the application of Soy Meal Hull (SMH), an agricultural by-product, for the removal of direct and acid dyes from aqueous solutions. Four textile dyes, C.I.Direct red 80 (DR80), C.I.Direct red 81 (DR81), C.I.Acid blue 92 (AB92) and C.I.Acid red 14 (AR14) were used as model compounds. Physical characteristics of SMH such as surface area, Fourier transform infra-red (FTIR) and scanning electron microscopy (SEM) were obtained. The surface area of SMH was found to be 0.7623 m²/g and the presence of functional groups such as hydroxyl, amine and carbonyl groups were detected. The effect of initial dye concentration, pH, contact time and SMH doses were elucidated at 20±1 °C. Results show that the pH value of 2 is favorable for the adsorption of all four dyes. The data evaluated for compliance with the Langmuir, Freundlich and BET isotherm models. It was found that data for DR80 and DR81 fitted well with Langmuir isotherm, for AB92, BET isotherm is preferred, while for AR14, the Freundlich isotherm is the most applicable. The adsorption capacities of SMH for DR80, DR81, AB92 and AR14 were, 178.57, 120.48, 114.94 and 109.89 mg/g of adsorbent, respectively. Also, adsorption kinetics of dyes was studied and the rates of sorption were found to conform to pseudo-second order kinetics with good correlation (R² ≥ 0.9977). Maximum desorption of ≥99.8% was achieved for DR80, DR81 and AB92 and 86% for AR14 in aqueous solution at pH 10. Based on the data of present investigation, one could conclude that the SMH being a natural, eco-friendly and low-cost adsorbent with relatively large adsorption capacity might be a suitable local alternative for elimination of dyes from colored aqueous solutions.

Keywords: Acid Dyes, Adsorbent, Adsorption, Adsorption Capacities, Adsorption Capacity, Adsorption Kinetics, Agricultural, Agricultural By-Product, Alternative, Application, Aqueous Solution, Aqueous Solutions, BET, Capacity, Characteristics, Compliance, Concentration, Correlation, Data, Desorption, Dye, Dye Removal, Dyes, Electron Microscopy, Equilibrium, Freundlich, Freundlich Isotherm, FTIR, Functional Groups, Investigation, Isotherm, Isotherms, Kinetics, Langmuir, Langmuir Isotherm, Local, Low Cost Adsorbent, Low-Cost Adsorbent, Model, Models, Natural Adsorbent, pH, pH Value, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second Order, Pseudo-Second Order Kinetics, Pseudo-Second-Order, Rates, Removal, Scanning Electron Microscopy, SEM, SMH, Solution, Solutions, Sorption, Surface, Surface Area, Value

? Hajjaji, M., Alami, A. and El Bouadili, A. (2006), Removal of methylene blue from aqueous solution by fibrous clay minerals. Journal of Hazardous Materials, 135 (1-3), 188-192.

Full Text: 2006\J Haz Mat135, 188.pdf

Abstract: Kinetics and equilibrium processes of the methylene blue (MB) retention from aqueous solution by a mixture of fibrous clay minerals, which was isolated from a naturally occurring clay, were investigated. For these purposes, the effects of contact time, initial adsorbate concentration, adsorbent content, pH and ionic strength were determined. The results show that the MB retention obeys a pseudo-first order equation and the process is a diffusion controlled solid-state reaction. Moreover, the isotherm data fitted the Langmuir equation and the MB binding process became more energetic with the increase of the adsorbent concentration. In addition, the augmentation of the clay content or the initial MB concentration reduced the adsorption capacity, presumably because of the clay particles microaggregation and/or the occurrence of MB deriving species. On the other hand, it is observed that the MB uptake limit is reduced in low acid pH, particularly below the PZC, as well as in ionic strengthen solutions. These facts are linked to the silanol group protonation and to the reduction of the electrostatic forces induced by the clay particles, respectively.

Keywords: Methylene Blue, Fibrous Clay Minerals, Retention, Kinetics, Isotherms

? Pehlivan, E., Cetin, S. and Yanık, B.H. (2006), Equilibrium studies for the sorption of zinc and copper from aqueous solutions using sugar beet pulp and fly ash. Journal of Hazardous Materials, 135 (1-3), 193-199.

Full Text: 2006\J Haz Mat135, 193.pdf

Abstract: In the present work, the abilities of native sugar beet pulp (SBP) and fly ash (FA) to remove copper (Cu²⁺) and zinc (Zn²⁺) ions from aqueous solutions were compared. The SBP and FA, an industrial by-product and solid waste of sugar industry, were used for the removal of copper and zinc from aqueous water. Batch adsorption experiments were performed in order to evaluate the removal efficiency of SBP and lignite-based FA. The effect of various operating variables, i.e. initial pH, adsorbent dose, initial metal ion concentration, and time on adsorption of copper and zinc onto the SBP and FA, has been studied. The sorption process was relatively fast and equilibrium was reached after about 60 min of contact. As much as 60–97% removal of copper and zinc for SBP and FA are possible in about 60 min, respectively, under the batch test conditions. Uptake showed a pH-dependent profile. The overall uptake for the SBP is at a maximum at pH 5.5 and gives up to 30.9 mg g⁻¹ for copper and at pH 6.0 and gives 35.6 mg g⁻¹ for zinc for SBP, which seems to be removed exclusively by ion exchange and physical sorption. Maximum adsorption of copper and zinc occurred 7.0 and 7.84 mg g⁻¹ at a pH value of 5.0 and 4.0 for FA, respectively. A dose of 8 g l⁻¹ of SBP and 8 g l⁻¹ FA were sufficient for the optimum removal of both the metal ions. The sorption data were represented by the Freundlich for SBP and the Langmuir and Freundlich for FA. The sorption data were better represented by the Langmuir isotherm than by the Freundlich one for FA in the adsorption of zinc ion, suggesting that the monolayer sorption, mainly due to ion exchange. The presence of low ionic strength or low concentration of Na and Cl ions does not have a significant effect on the adsorption of these metals by SBP and FA. The SBP and FA are shown to be effective metal adsorbents for these two metals.

Keywords: Adsorption, Sugar Beet Pulp, Fly Ash, Copper and Zinc, Sorption Isotherms

? Hung, H.W. and Lin, T.F. (2006), Adsorption of MTBE from contaminated water by carbonaceous resins and mordenite zeolite. Journal of Hazardous Materials, 135 (1-3), 210-217.

Full Text: 2006\J Haz Mat135, 210.pdf

Abstract: Equilibrium and kinetic adsorption of methyl tert-butyl ether (MTBE) onto two carbonaceous resins and one zeolite was elucidated in this study. The Freundlich isotherm is adequate for describing the adsorption equilibrium of MTBE onto all the tested adsorbents in deionized water and natural waters. The resins of Ambersorb 563 and 572 have the highest adsorption capacity and almost twice the capacity of mordenite in deionized water. A different extent of NOM competition with MTBE was found for the carbonaceous resins in natural waters. For mordenite, no competitive adsorption was observed in natural water. The ideal adsorbed solution theory combined with equivalent background compound (IAST-EBC) model successfully described and predicted the adsorption of MTBE onto the carbonaceous resins in natural waters. The pore diffusion and micropore diffusion model fit the experimental data fairly well and successfully predicted the transport of MTBE within the adsorbent under different operating conditions. The small tortuosity factor between 1.2 and 2.3 of the resins for the diffusion of MTBE was observed, indicating a superior transport property for the carbonaceous resins in natural waters. The intracrystalline diffusivity of MTBE in natural water was much slower than that in deionized water, only 1/10 in STL and 1/3 in FS natural water, since the aperture entrances of mordenite was appreciably hindered by NOM.

Keywords: Adsorption, MTBE, NOM, Resin, Zeolite

? Demirbas, A., Sari, A. and Isildak, O. (2006), Adsorption thermodynamics of stearic acid onto bentonite. Journal of Hazardous Materials, 135 (1-3), 226-231.

Full Text: 2006\J Haz Mat135, 226.pdf

Abstract: Adsorption equilibrium of stearic acid onto natural bentonite with Turkish origin was studied at the temperatures of 298, 308 and 318 K. SEM and XRD analysis show that the bentonite used as adsorbent is composed of microcrystal and porous structure. The specific surface area was determined by BET method as 38.6 m²/g. The adsorption of stearic acid onto bentonite was conformed to the Langmiur and Freundlich isotherms. The equilibrium parameter, RL revealed that the bentonite is a good adsorbent for stearic acid. The sorption capacity of bentonite studied decreases with increasing temperature. However, it is concluded that the adsorption capacity of bentonite for the stearic acid under the same experimental conditions is in comparable level in terms of that of the rice husk ash given in literature. Thermodynamic parameters, G_ads, was calculated to be between −21.8 and −22.8 kJ mol⁻¹. H_ads and S_ads were found to be −9.2 kJ mol⁻¹ and 42.4 J mol⁻¹ K⁻¹, respectively. These parameters obtained as a function of temperature indicate that the adsorption of stearic acid onto bentonite was a spontaneous and an exothermic process. An FT-IR study on the adsorbed material was used to verify the interaction of the stearic molecule with bentonite after adsorption process.

Keywords: Adsorption, Bentonite, Stearic Acid, Thermodynamic Parameters

? Başar, C.A. (2006), Applicability of the various adsorption models of three dyes adsorption onto activated carbon prepared waste apricot. Journal of Hazardous Materials, 135 (1-3), 232-241.

Full Text: 2006\J Haz Mat135, 232.pdf

Abstract: In this study, activated carbon (WA11Zn5) was prepared from waste apricot, which is waste in apricot plants in Malatya, by chemical activation with ZnCl₂. BET surface area of activated carbon is determined as 1060 m²/g. Activated carbon includes both micro and mesopores. Percentages of micropores and mesopores area are determined 36% and 74%, percentage of micropores and mesopores volume is 19% and 81%, respectively. The ability of WA11Zn5, to remove three dyes, methylene blue (MB), malachite green (MG), and crystal violet (CV), from effluent solutions by adsorption has been studied. The adsorption capacities of WA11Zn5 decreases in the order malachite green (MG) > methylene blue (MB) > crystal violet (CV). Equilibrium isotherms for the adsorption of three dyes on activated carbon were measured experimentally. Results were analyzed by the Langmiur, Freundlich, Dubinin–Redushkevich (D–R), Temkin, Frumkin, Harkins–Jura, Halsey and Henderson equation using linearized correlation coefficient at different temperature. The characteristic parameters for each isotherm have been determined. Models and the isotherm constant were evaluated depending on temperature. Langmiur and Frumkin equation is found to best represent the equilibrium data for three dye-WA11Zn5 systems.

Keywords: Activated Carbon, Activation, Adsorption, Adsorption Capacities, BET, BET Surface Area, Carbon, Chemical, Chemical Activation, Correlation, Correlation Coefficient, Crystal Violet, CV, Data, Dye, Dyes, Equilibrium, Equilibrium Isotherms, Freundlich, Isotherm, Isotherms, Malachite Green, MB, Methylene Blue, MG, Models, Plants, Solutions, Surface, Surface Area, Systems, Temperature, Volume, Waste, ZnCl₂

? Ajmal, M., Rao, R.A.K., Ahmad, R. and Khan, M.A. (2006), Adsorption studies on Parthenium hysterophorous weed: Removal and recovery of Cd(II) from wastewater. Journal of Hazardous Materials, 135 (1-3), 242-248.

Full Text: 2006\J Haz Mat135, 242.pdf

Abstract: The efficiency of parthenium weed as an adsorbent for removing Cd(II) from water has been studied. Parthenium is found to exhibit substantial adsorption capacity over a wide range of initial Cd(II) ions concentration. Effect of time, temperature, pH and concentration on the adsorption of Cd(II) was investigated by batch process. Pseudo-first-order and Pseudo-second-order models were evaluated. The kinetics data for the adsorption process obeyed second-order rate equation. The equilibrium data could be described well by the Langmuir and Freundlich isotherms. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were calculated. The adsorption process was found to be endothermic and spontaneous. The maximum adsorption of Cd(II) ions (99.7%) in the pH range 3–4 indicated that material could be effectively utilized for the removal of Cd(II) ions from wastewater. The desorption studies showed 82% recovery of Cd(II) when 0.1 M HCl solution was used as effluent.

Keywords: Adsorbent, Adsorption, Adsorption Capacity, Adsorption Dynamics, Adsorption Kinetics, Batch, Batch Process, Breakthrough Capacity, Capacity, Cd(II), Cd(II) Ions, Concentration, Data, Desorption, Desorption Studies, Efficiency, Endothermic, Equilibrium, Freundlich, Freundlich Isotherm, Isotherms, Kinetics, Langmuir, Langmuir and Freundlich Isotherms, Langmuir Isotherm, Models, Parthenium, pH, Pseudo-First-Order, Pseudo-Second-Order, Recovery, Removal, Second Order, Second-Order, Solution, Temperature, Thermodynamic, Thermodynamic Parameters, Wastewater, Water, Weed

? Hamdaoui, O. (2006), Batch study of liquid-phase adsorption of methylene blue using cedar sawdust and crushed brick. Journal of Hazardous Materials, 135 (1-3), 264-273.

Full Text: 2006\J Haz Mat135, 264.pdf

Abstract: This paper presents a study on the batch adsorption of basic dye, methylene blue, from aqueous solution (40 mg L⁻¹) onto cedar sawdust and crushed brick in order to explore their potential use as low-cost adsorbents for wastewater dye removal. Adsorption isotherms were determined at 20°C and the experimental data obtained were modelled with the Langmuir, Freundlich, Elovich and Temkin isotherm equations. Adsorption kinetic data determined at a temperature of 20°C were modelled using the pseudo-first and pseudo-second-order kinetic equations, liquid-film mass transfer and intra-particle diffusion models. By considering the experimental results and adsorption models applied in this study, it can be concluded that equilibrium data were represented well by a Langmuir isotherm equation with maximum adsorption capacities of 142.36 and 96.61 mg g⁻¹ for cedar sawdust and crushed brick, respectively. The second-order model best describes adsorption kinetic data. Analysis of adsorption kinetic results indicated that both film- and particle-diffusion are effective adsorption mechanisms. The Influence of temperature and pH of the solution on adsorption process were also studied. The extent of the dye removal decreased with increasing the solution temperature and optimum pH value for dye adsorption was observed at pH 7 for both adsorbents. The results indicate that cedar sawdust and crushed brick can be attractive options for dye removal from dilute industrial effluents.

Keywords: Adsorbents, Adsorption, Adsorption Capacities, Adsorption Isotherms, Adsorption Kinetic, Aqueous Solution, Basic Dye, Batch, Batch Adsorption, Batch Study, Cedar Sawdust, Crushed Brick, Data, Diffusion, Dye, Dye Adsorption, Dye Removal, Effluents, Elovich, Equilibrium, Experimental, Freundlich, Intra-Particle Diffusion, Intraparticle Diffusion, Isotherm, Isotherm Equations, Isotherms, Kinetic, Kinetic Equations, Kinetics, Langmuir, Langmuir Isotherm, Liquid-Phase Adsorption, Low Cost Adsorbents, Low-Cost Adsorbents, Mass Transfer, Mechanisms, Methylene Blue, Model, Models, Options, Particle Diffusion, pH, pH Value, Potential, Pseudo Second Order, Pseudo-First and, Pseudo-Second-Order, Removal, Sawdust, Second Order, Second-Order, Second-Order Model, Solution, Temkin Isotherm, Temperature, Value, Wastewater

? Mohan, D., Singh, K.P. and Singh, V.K. (2006), Trivalent chromium removal from wastewater using low cost activated carbon derived from agricultural waste material and activated carbon fabric cloth. Journal of Hazardous Materials, 135 (1-3), 280-295.

Full Text: 2006\J Haz Mat135, 280.pdf

Abstract: An efficient adsorption process is developed for the decontamination of trivalent chromium from tannery effluents. A low cost activated carbon (ATFAC) was prepared from coconut shell fibers (an agricultural waste), characterized and utilized for Cr(III) removal from water/wastewater. A commercially available activated carbon fabric cloth (ACF) was also studied for comparative evaluation. All the equilibrium and kinetic studies were conducted at different temperatures, particle size, pHs, and adsorbent doses in batch mode. The Langmuir and Freundlich isotherm models were applied. The Langmuir model best fit the equilibrium isotherm data. The maximum adsorption capacities of ATFAC and ACF at 25 °C are 12.2 and 39.56 mg/g, respectively. Cr(III) adsorption increased with an increase in temperature (10 °C: ATFAC—10.97 mg/g, ACF—36.05 mg/g; 40 °C: ATFAC—16.10 mg/g, ACF—40.29 mg/g). The kinetic studies were conducted to delineate the effect of temperature, initial adsorbate concentration, particle size of the adsorbent, and solid to liquid ratio. The adsorption of Cr(III) follows the pseudo-second-order rate kinetics. From kinetic studies various rate and thermodynamic parameters such as effective diffusion coefficient, activation energy and entropy of activation were evaluated. The sorption capacity of activated carbon (ATFAC) and activated carbon fabric cloth is comparable to many other adsorbents/carbons/biosorbents utilized for the removal of trivalent chromium from water/wastewater.

Keywords: ACF, Activated Carbon, Activated Carbons, Activation, Activation Energy, Adsorbent, Adsorption, Adsorption Capacities, Agricultural, Agricultural Waste, Batch, Batch Mode, Capacity, Carbon, Chromium, Chromium Removal, Coconut Shell, Concentration, Cost, Cr(III), Cr(III) Adsorption, Data, Decontamination, Diffusion, Diffusion Coefficient, Effluents, Energy, Entropy, Equilibrium, Equilibrium and Kinetic Studies, Equilibrium Isotherm, Evaluation, Fibers, Freundlich, Freundlich Isotherm, Isotherm, Kinetic, Kinetic Studies, Kinetics, Langmuir, Langmuir Model, Low Cost Adsorbents, Mode, Model, Models, Particle Size, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Rate, Rate Kinetics, Removal, Size, Sorption, Sorption Capacity, Tannery Wastewater, Temperature, Thermodynamic, Thermodynamic Parameters, Trivalent Chromium, Utilization of Agricultural Waste Materials, Waste, Wastewater, Wastewater Treatment

? Malkoc, E. and Nuhoglu, Y. (2006), Removal of Ni(II) ions from aqueous solutions using waste of tea factory: Adsorption on a fixed-bed column. Journal of Hazardous Materials,