Personal Research Database

Full Text: 2007\J Haz Mat143, 478.pdf

Abstract: In the present study biosorption technique, the accumulation of metals by biomass was used for the removal of nickel from aqueous medium. The rice bran in its acid treated (H₃PO₄) form was used as a low cost sorbent. The adsorption characteristics of nickel on protonated rice bran were evaluated as a function of pH, biosorbent size, biosorbent dosage, initial concentration of nickel and time. Within the tested pH range (pH 1–7), the protonated rice bran displayed more resistance to pH variation, retaining up to 102 mg/g of the nickel binding capacity at pH 6. Meanwhile, at lower pH values the uptake capacity decreased. The % age removal of nickel was maximum at 0.25 g of biosorbent dose and 0.25 mm biosorbent size. At the optimal conditions, metal ion uptake was increased as the initial metal ion concentration increased up to 100 mg/L. Kinetic and isotherm experiments were carried out at the optimal pH 6.0 for nickel. The metal removal rate was rapid, with 57% of the total adsorption taking place within 15–30 min. The Freundlich and Langmuir models were used to describe the uptake of nickel on protonated rice bran. The Langmuir and Freundlich model parameters were evaluated. The equilibrium adsorption data was better fitted to Langmuir adsorption isotherm model. The adsorption followed pseudo second-order kinetic model. The thermodynamic assessment of the metal ion-rice bran biomass system indicated the feasibility and spontaneous nature of the process and ΔG° values were evaluated as ranging from −22.82 to −24.04 kJ/mol for nickel sorption. The order of magnitude of the ΔG° values indicated an ion-exchange physiochemical sorption process.

Keywords: Accumulation, Adsorption, Adsorption Isotherm, Adsorption Isotherm Model, Adsorption Isotherms, Age, Aqueous Medium, Assessment, Biomass, Biosorbent, Biosorption, Capacity, Characteristics, Concentration, Cost, Data, Equilibrium, Experiments, Feasibility, Freundlich, Freundlich Model, Function, Ion Exchange, Ion-Exchange, Ionexchange, Isotherm, Isotherm Model, Kinetic, Kinetic Model, Langmuir, Langmuir Adsorption Isotherm, Langmuir and Freundlich Model, Metal, Metals, Model, Models, Nickel, pH, Pseudo Second Order, Pseudo Second-Order, Pseudo-Second-Order, Removal, Resistance, Rice, Rice Bran, Second Order, Second-Order, Size, Sorbent, Sorption, Sorption Process, Thermodynamic, Uptake, Water Treatment

? Preetha, B. and Viruthagiri, T. (2007), Application of response surface methodology for the biosorption of copper using Rhizopus arrhizus. Journal of Hazardous Materials, 143 (1-2), 506-510.

Full Text: 2007\J Haz Mat143, 506.pdf

Abstract: Response surface methodology was used to study the cumulative effect of the various parameters namely, initial copper ion concentration, pH, temperature, biomass loading and to optimize the process conditions for the maximum removal of copper. For obtaining the mutual interaction between the variables and optimizing these variables, a 2⁴ full factorial central composite design using response surface methodology was employed. The analysis of variance (ANOVA) of the quadratic model demonstrates that the model was highly significant. The model was statistically tested and verified by experimentation. A maximum copper removal of 98% was obtained using the biosorption kinetics of copper under optimum conditions.

Keywords: Biosorption, Rhizopus Arrhizus, Design of Experiments, Central Composite Design, Response Surface Methodology

? Estevinho, B.N., Martins, I., Ratola, N., Alves, A. and Santos, L. (2007), Removal of 2,4-dichlorophenol and pentachlorophenol from waters by sorption using coal fly ash from a Portuguese thermal power plant. Journal of Hazardous Materials, 143 (1-2), 535-540.

Full Text: 2007\J Haz Mat143, 535.pdf

Abstract: Chlorophenols are one of the most important groups of priority pollutants, due to their high toxicity, mutagenicity and carcinogenicity. Although activated carbon has been the preferred choice for the removal of such pollutants from wastewaters, the search for cheaper alternative sorbents became common in the last years. Fly ash, a by-product from coal burning power plants, has a surface composition that may enable the sorption of specific organic compounds. Therefore, this feasibility study presents the optimization of the operating parameters of a fixed-bed column containing fly ash particles, percolated by aqueous solutions of 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) with concentrations of 1 and 100 μg/ml. Both chlorophenols were analysed by gas chromatography with electron capture detection (GC-ECD), after solid-phase microextraction (SPME), with limits of detection (LODs) of 7.28 μg/l for 2,4-DCP and 1.76 μg/l for PCP. Removal efficiencies above 99% were obtained for an initial concentration of 10 μg/ml of chlorophenols. Column saturation was achieved after 7 h of continuous operation for 2,4-DCP and 10 h for the PCP for feed levels of 10 μg/ml. Fly ash exhibited more affinity towards the sorption of PCP, in comparison to 2,4-DCP.

Keywords: Coal Fly Ash, Sorption, Pentachlorophenol, Dichlorophenol, Solid-Phase Microextraction, Tapada Do Outeiro Thermal Power Plant

? Huang, J.H., Liu, Y.F., Jin, Q.Z., Wang, X.G. and Yang, J. (2007), Adsorption studies of a water soluble dye, Reactive Red MF-3B, using sonication-surfactant-modified attapulgite clay. Journal of Hazardous Materials, 143 (1-2), 541-548.

Full Text: 2007\J Haz Mat143, 541.pdf

Abstract: The removal of water-soluble Reactive Red MF-3B from aqueous media by sonication-surfactant-modified attapulgite clay was studied in a batch system. The surfactant used was octodecyl trimethyl ammonium chloride (OTMAC). Adsorbent characterizations were investigated using X-ray diffraction, infrared spectroscopy, and surface area analysis. The effects of pH, contact time, initial solute concentration, adsorbent dose, and temperature on the adsorption of Reactive Red MF-3B onto modified clay were investigated. On the basis of kinetic studies, specific rate constants involved in the processes were calculated and second-order adsorption kinetics was observed in the case. Film diffusion was found to be the rate-limiting step. Reactive Red MF-3B adsorption was found to increase with increase temperature. The Reactive Red MF-3B equilibrium adsorption data were fitted to Freundlich and Langmuir isotherm models, the former being found to provide the better fit of the experimental data. Thermodynamic parameters were calculated. From the results it can be concluded that the surfactant-modified clay could be a good adsorbent for treating Reactive Red MF-3B-contaminated waters.

Keywords: Sonicate, Attapulgite, Octodecyl Trimethyl Ammonium Chloride, Adsorption, Reactive Red MF-3B

? Rubio, B., Izquierdo, M.T., Mayoral, M.C., Bona, M.T. and Andres, J.M. (2007), Unburnt carbon from coal fly ashes as a precursor of activated carbon for nitric oxide removal. Journal of Hazardous Materials, 143 (1-2), 561-566.

Full Text: 2007\J Haz Mat143, 561.pdf

Abstract: The aim of this work is to evaluate the characteristics of an activated carbon obtained from unburnt carbon in coal fly ashes to be used in the removal of NO. Carbon-rich fraction was obtained by mechanical sieving of fly ashes. The mineral matter was removed by conventional HCl and HF demineralization procedure. Activation was carried out with steam at 900 °C in order to develop porosity onto the sample. Characterization of samples was performed by several techniques with a main objective: to follow the mineral matter content, composition and distribution on the samples in order to better understand how to remove it from unburnt carbon in fly ashes. To study the use of this unburnt carbon as a precursor for the preparation of activated carbons for gas cleaning, the NO removal by ammonia using activated carbon as a catalyst at low temperature was performed. Results show a good performance of activated carbon in this reaction that is in relationship with BET surface area.

Keywords: Coal Fly Ash, Activated Carbon, NO Removal

? Shi, B.Y., Li, G.H., Wang, D.S., Feng, C.H. and Tang, H.X. (2007), Removal of direct dyes by coagulation: The performance of preformed polymeric aluminum species. Journal of Hazardous Materials, 143 (1-2), 567-574.

Full Text: 2007\J Haz Mat143, 567.pdf

Abstract: Removal of three direct dyes (Direct Black 19, Direct Red 28, and Direct Blue 86) by coagulation with three different Al based coagulants was investigated. The main purpose of this paper is to examine the coagulation features of polymeric aluminum coagulants in treatment of dye-polluted waters and the emphasis was placed on the roles of preformed Al species, particularly Al₁₃. The performance of Al₁₃ in coagulation of dyes was observed through jar tests by comparing traditional Al salt, polyaluminum chloride (PACl), and purified Al₁₃. The results showed that under most cases Al₁₃ had significantly higher efficiency in removal of direct dyes than traditional Al salt and commercial PACl with the exception of Direct Red 28 removal under high pH range. The coagulation of direct dyes could be greatly affected by pH. Reducing pH was favorable for preformed Al species in a broad pH range. For traditional Al coagulant, efficient dye removal only occurred in a relatively narrow pH range of near 6.0. The outstanding coagulation behavior of Al₁₃ could be ascribed to its high charge neutralization ability, relative stability and potential self-assembly tendency.

Keywords: Direct Dye, Coagulation, Al Speciation, Polyaluminum Chloride, Al₁₃

? Stylianou, M.A., Hadjiconstantinou, M.P., Inglezakis, V.J., Moustakas, K.G. and Loizidou, M.D. (2007), Use of natural clinoptilolite for the removal of lead, copper and zinc in fixed bed column. Journal of Hazardous Materials, 143 (1-2), 575-581.

Full Text: 2007\J Haz Mat143, 575.pdf

Abstract: This work deals with the removal of lead, copper and zinc from aqueous solutions by using natural zeolite (clinoptilolite). Fixed bed experiments were performed, using three different volumetric flow rates of 5, 7 and 10 bed volume/h, under a total normality of 0.01N, at initial pH of 4 and ambient temperature (25 °C). The removal efficiency increased when decreasing the flow rate and the following selectivity series was found: Pb²⁺ > Zn²⁺ ≥ Cu²⁺. Conductivity measurements showed that lead removal follows mainly ion exchange mechanism, while copper and zinc removal follows ion exchange and sorption mechanism as well.

Keywords: Ion Exchange, Copper, Lead, Zinc, Clinoptilolite, Fixed Bed

? Kumar, K.S., Ganesan, K. and Rao, P.V.S. (2007), Phycoremediation of heavy metals by the three-color forms of Kappaphycus alvarezii. Journal of Hazardous Materials, 143 (1-2), 590-592.

Full Text: 2007\J Haz Mat143, 590.pdf

Abstract: In the present investigation, three living color forms (brown, green and pale yellow) of Kappaphycus alvarezii were examined for their biosorption ability in the laboratory. The brown color form proved to be an excellent metal biosorbent, i.e. it could adsorb good amount of cadmium 3.064 mg/100 g f.wt. and cobalt 3.365 mg/100 g f.wt. It also removed 2.799 mg/100 g f.wt. of chromium. The green color form absorbed 2.684, 3.43 and 2.692 mg/100 g f.wt. of cadmium, cobalt and chromium, respectively. In contrast, the pale yellow form removed almost equal proportion of cadmium 0.961 mg/100 g f.wt. and chromium 0.942 mg/100 g f.wt. It also removed 1.403 mg/100 g f.wt. cobalt. Thus, the living color forms of this seaweed could form an effective biosorbent material for removal of heavy metals.

Keywords: Biosorption, Color Forms, Heavy Metals, Kappaphycus Alvarezii, Marine

? Kumar, K.V. and Porkodi, K. (2007), Comments on “adsorption of 4-chlorophenol from aqueous solutions by xad-4 resin: Isotherm, kinetic, and thermodynamic analysis”. Journal of Hazardous Materials, 143 (1-2), 598-599.

Full Text: 2007\J Haz Mat143, 598.pdf

Abstract: This letter reports the importance and advantages of the constraints in the Redlich Peterson isotherm exponent.

Keywords: Isotherm, Redlich Peterson, Langmuir, Theory, Constraints

? Sarı, A., Tuzen, M. and Soylak, M. (2007), Adsorption of Pb(II) and Cr(III) from aqueous solution on Celtek clay. Journal of Hazardous Materials, 144 (1-2), 41-46.

Full Text: 2007\J Haz Mat144, 41.pdf

Abstract: This paper presents the adsorption of Pb(II) and Cr(III) from aqueous solution on Celtek clay. Batch experiments were carried out as a function of the adsorbent dosage, solution pH, shaking time, and temperature. The equilibrium data of fitted well with the linear Langmuir and Freundlich models. Dubinin–Radushkevick (D–R) isotherm model was applied to describe the nature of the adsorption of the metals, and found that it occurred physically. Thermodynamic parameters, the change in Gibbs free energy change (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were also calculated. These parameters indicated that the adsorption of Pb(II) and Cr(III) on Celtek clay was feasible, spontaneous and exothermic process in nature. Based on the results, it was concluded that Celtek clay had a significant potential for removing Pb(II) and Cr(III) from wastewater using adsorption method.

Keywords: Lead, Chromium, Celtek Clay, Adsorption Isotherm, Thermodynamic Parameter

? Daneshvar, N., Aber, S., Khani, A. and Khataee, A.R. (2007), Study of imidaclopride removal from aqueous solution by adsorption onto granular activated carbon using an on-line spectrophotometric analysis system. Journal of Hazardous Materials, 144 (1-2), 47-51.

Full Text: 2007\J Haz Mat144, 47.pdf

Abstract: The removal of imidaclopride as a pesticide by granular activated carbon (GAC) and its adsorption kinetics were studied at different pH values and temperatures. In all experiments, the amount of GAC and initial concentration of imidaclopride were 2 g and 25 ppm, respectively. The adsorption process was followed by an on-line spectrophotometric analysis system, which consisted of UV-spectrophotometer, a designed absorption cell, peristaltic pump and special glassy reactor. The effect of pH and temperature on adsorption was studied over 90 min adsorption periods. The obtained data were treated according to various kinetic models. The results showed that second order model was the most suitable one on the overall. The our results also showed that the adsorption rate constants for first order, second order and intraparticle diffusion models followed decreasing order: pH = 7 > 4 > 10 > 1, T = 25 > 35 > 45 > 55 °C.

Keywords: Absorption, Activated Carbon, Adsorption, Adsorption Kinetics, Adsorption Process, Adsorption Rate, Analysis, Aqueous Solution, Atrazine, Carbon, Cloth, Concentration, Constants, Diffusion, Diffusion Models, Effect of pH, Fibers, First Order, GAC, Granular, Granular Activated Carbon, Imidaclopride, Intraparticle Diffusion, Kerolite, Kinetic, Kinetic Models, Kinetics, Model, Models, On-Line Spectrophotometric Analysis System, Order, Pesticide, Pesticides, pH, pH Values, Process, Rate, Rate Constants, Reactor, Removal, Second Order, Temperature, Temperatures, Water, Water Treatment

? Wu, C.H. (2007), Adsorption of reactive dye onto carbon nanotubes: Equilibrium, kinetics and thermodynamics. Journal of Hazardous Materials, 144 (1-2), 93-100.

Full Text: 2007\J Haz Mat144, 93.pdf

Abstract: The adsorption efficiency of carbon nanotubes for Procion Red MX-5B at various pHs and temperatures was examined. The amount adsorbed increased with the CNTs dosage; however, the adsorption capacity initially increased with the CNTs dosage (<0.25 g/l) and then declined as the CNTs dosage increased further (>0.25 g/l). The linear correlation coefficients and standard deviations of Langmuir and Freundlich isotherms were determined and the results revealed that Langmuir isotherm fitted the experimental results well. Kinetic analyses were conducted using pseudo first- and second-order models and the intraparticle diffusion model. The regression results showed that the adsorption kinetics were more accurately represented by a pseudo second-order model. Changes in the free energy of adsorption (ΔG°), enthalpy (ΔH°) and entropy (ΔS°), as well as the activation energy (E_a) were determined. ΔH° and ΔS° were 31.55 kJ/mol and 216.99 J/mol K, respectively, at pH 6.5 and 41.47 kJ/mol and 244.64 J/mol K at pH 10. The activation energy was 33.35 kJ/mol at pH 6.5. ΔH°, ΔG° and E_a all suggested that the adsorption of Procion Red MX-5B onto CNTs was by physisorption.

Keywords: Acid-Blue-193, Activation, Activation Energy, Adsorption, Adsorption Capacity, Adsorption Efficiency, Adsorption Kinetics, Anionic Dyes, Aqueous-Solutions, Capacity, Carbon, Carbon Nanotubes, Ceria Nanoparticles, Correlation, Diffusion, Diffusion Model, Dosage, Dye, Efficiency, Energy, Enthalpy, Entropy, Experimental, Fly-Ash, Free Energy, Free Energy of Adsorption, Freundlich, Freundlich Isotherms, Intraparticle Diffusion, Intraparticle Diffusion Model, Isotherm, Isotherms, Kinetics, Langmuir, Langmuir and Freundlich Isotherms, Langmuir Isotherm, Langmuir-Isotherm, Linear, Methylene-Blue, Model, Models, pH, Photocatalytic Activity, Physisorption, Pseudo Second Order, Pseudo Second-Order, Pseudo Second-Order Model, Pseudo-Second-Order, Reactive Dye, Regression, Removal, Second Order, Sepiolite, Standard, Temperatures, Thermodynamics, Water

? Sayilkan, F., Asiltürk, M., Tatar, P., Kiraz, N., Arpat, E. and Sayilkan, H. (2007), Photocatalytic performance of Sn-doped TiO₂ nanostructured mono and double layer thin films for Malachite Green dye degradation under UV and vis-lights. Journal of Hazardous Materials, 144 (1-2), 140-146.

Full Text: 2007\J Haz Mat144, 140.pdf

Abstract: Nanostructure Sn⁴⁺-doped TiO₂ based mono and double layer thin films, contain 50% solid ratio of TiO₂ in coating have been prepared on glass surfaces by spin-coating technique. Their photocatalytic performances were tested for degradation of Malachite Green dye in solution under UV and vis irradiation. Sn⁴⁺-doped nano-TiO₂ particle a doping ratio of about 5[Sn⁴⁺, Ti(OBun)₄; mol, mol%] has been synthesized by hydrotermal process at 225C. The structure, surface and optical properties of the thin films and, or the particles have been investigated by XRD, BET and UV, vis, NIR techniques. The results showed that the double layer coated glass surfaces have a very high photocatalytic performance than the other one under UV and vis lights. The results also proved that the hydrothermally synthesized nano-TiO₂ particles are fully anatase crystalline form and are easily dispersed in water. The results also reveal that the coated surfaces have hydrophilic property.

Keywords: Anatase, BET, Coated, Coating, Degradation, Dye, Dye Degradation, Glass, Hydrothermal Process, Irradiation, Malachite Green, Malachite-Green, Nano-TiO₂, Optical Properties, Particles, Performance, Photocatalysis, Photocatalytic, Property, Sn-Doping, Sn⁴⁺-Doped TiO₂, Solution, Structure, Surface, Surfaces, Techniques, Thin Film, TiO₂, UV, Water, XRD

? Özer, D., Dursun, G. and Özer, A. (2007), Methylene blue adsorption from aqueous solution by dehydrated peanut hull. Journal of Hazardous Materials, 144 (1-2), 171-179.

Full Text: 2007\J Haz Mat144, 171.pdf

Abstract: Dyes are colour organic compounds which can colorize the other substances. These substances usually presents in the effluent water of many industries, such as textiles, leather, paper, printing and cosmetics. To observe the potential feasibility of removing colour, peanut hull as an agricultural by-product was dehydrated with sulphuric acid (DPH) and used for adsorption of methylene blue (MB) from aqueous solution. The effects of various parameters such as initial methylene blue concentrations, temperatures and particle sizes were examined and optimal experimental conditions were determined. Adsorption data were well described by the Langmuir model, although they could be modelled by the Freundlich model as well. The adsorption process followed the pseudo-second order kinetic model. The mass transfer model as intraparticle diffusion was applied to the experimental data to examine the mechanisms of rate controlling step. It was found that at the higher initial MB concentration, intraparticle diffusion is becoming significant controlling step. The thermodynamic constants of the adsorption process were also evaluated by using the Langmuir constants related to the equilibrium of adsorption at different temperatures. The results in this study indicated that dehydrated peanut hull was a good adsorbent for removing methylene blue.

Keywords: Acid, Activated Carbon, Adsorbent, Adsorption, Adsorption From Aqueous Solution, Adsorption Process, Agricultural, Agricultural By-Product, Aqueous Solution, Basic-Dyes, By-Product, Colour, Concentration, Concentrations, Constants, Copper(II), Dehydrated Peanut Hull (DPH), Diffusion, Effects, Effluent, Equilibrium, Equilibrium, Experimental, Experimental Data, Freundlich, Freundlich Model, Industry Waste-Water, Intraparticle Diffusion, Kinetic, Kinetic Model, Kinetics, Langmuir, Langmuir Constants, Langmuir Model, Leather, Mass Transfer, Mass Transfer Model, Mass-Transfer, MB, Mechanism, Mechanisms, Methylene Blue, Model, Order, Organic, Organic Compounds, Paper, Parameters, Particle, Peanut, Peanut Hull, Process, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-Second Order, Pseudo-Second Order Kinetic Model, Pseudo-Second-Order, Rate, Removal, Sorption, Sulphuric Acid, Temperatures, Textiles, Thermodynamic, Thermodynamic Parameters, Transfer, Water, Wheat Bran

? Liu, H.N., Li, G.T., Qu, J.H. and Liu, H.J. (2007), Degradation of azo dye Acid Orange 7 in water by Fe⁰/granular activated carbon system in the presence of ultrasound. Journal of Hazardous Materials, 144 (1-2), 180-186.

Full Text: 2007\J Haz Mat144, 180.pdf

Abstract: Degradation of azo dye Acid Orange 7 (AO7) was investigated using zero-valent iron/granular activated carbon (Fe⁰/GAC) in the absence and presence of ultrasound (US). The AO7 degradation efficiency by Fe⁰/GAC was dramatically enhanced by ultrasound, ultrasound alone had a little effect on the degradation. Effects of Fe⁰/GAC ratios and initial pH values on AO7 degradation were studied in the US–Fe⁰/GAC system. The degradation followed the pseudo-first-order kinetics model. The pseudo-first-order rate constant of AO7 degradation by Fe⁰/GAC was 8.74×10⁻³ min⁻¹ while that by US–Fe⁰/GAC was 3.91×10⁻² min⁻¹. A significant synergetic effect was observed between US and Fe⁰/GAC. Ultrasound swept the reactive intermediates or products from Fe⁰ surface, and thereby the surface of Fe⁰ was cleaned and reactivated. Granular activated carbon was added as cathode to increase the unit of internal batteries and enhance the current efficiency of the internal electrolysis. The suitable Fe⁰/GAC ratio (v/v) for the degradation of AO7 in the presence of ultrasound was 1:1. The degradation was highly dependent on pH, and a decrease of the initial pH values from 12.0 to 4.0 led to the increase of degradation efficiencies. Sulfanilamide was proved as the main residual degradation product in the solution by the analysis of high-performance liquid chromatograms.

Keywords: Zero-Valent Iron, Synergetic Effect, Ultrasound, Granular Activated Carbon, Acid Orange 7

? Wang, J.P., Feng, H.M. and Yu, H.Q. (2007), Analysis of adsorption characteristics of 2,4-dichlorophenol from aqueous solutions by activated carbon fiber. Journal of Hazardous Materials,