Personal Research Database

Full Text: J\J Haz Mat122, 161.pdf

Abstract: The removal of Cd(II), Pb(II), Hg(II), Cu(II), Ni(II), Mn(II) and Zn(II) by carbon aerogel has been found to be concentration, pH, contact time, adsorbent dose and temperature dependent. The adsorption parameters were determined using both Langmuir and Freundlich isotherm models. Surface complexation and ion exchange are the major removal mechanisms involved. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on carbon aerogel satisfies not only the Langmuir assumptions but also the Freundlich assumptions, i.e. multilayer formation on the surface of the adsorbent with an exponential distribution of site energy.

The applicability of the Lagergren kinetic model has also been investigated. Thermodynamic constant (K_ad), standard free energy (ΔG⁰), enthalpy (ΔH⁰) and entropy (ΔS⁰) were calculated for predicting the nature of adsorption. The results indicate the potential application of this method for effluent treatment in industries and also provide strong evidence to support the adsorption mechanism proposed.

Keywords: Activated Carbons, Adsorbent, Adsorbent Dose, Adsorption, Adsorption, Adsorption Isotherm, Adsorption Mechanism, Aerogel, Agricultural by-Products, Application, Aqueous Solutions, Assumptions, Behaviour, Cadmium, Carbon, Carbon Aerogel, Cd(II), Chromium, Complexation, Concentration, Contact, Copper, Cu(II), Distribution, Energy, Enthalpy, Entropy, Evidence, Exchange, Freundlich, Freundlich Isotherm, Heavy Metal, Heavy Metal Ions, Hg(II), Industry Waste-Water, Ion Exchange, Ion-Exchange, Ions, Isotherm, Isotherm Models, Jun, Kinetic, Kinetic Model, Lagergren, Langmuir, Mechanism, Mechanisms, Mercury(II), Metal, Metal Ions, Model, Models, Multilayer, Ni(II), Pb(II), Peanut Hull Carbon, pH, Potential, Removal, Rights, Site, Solutions, Sorption, Standard, Support, Surface, Temperature, Thermodynamic, Time, Treatment, Wastewater, Zn(II)

? Ajmal, M., Rao, R.A.K. and Khan, M.A. (2005), Adsorption of copper from aqueous solution on Brassica cumpestris (mustard oil cake). Journal of Hazardous Materials, 122 (1-2), 177-183.

Full Text: 2005\J Haz Mat122, 177.pdf

Abstract: The adsorption behavior of various heavy metals on mustard oil cake (MOC) was studied. The maximum adsorption of Cu(II) was observed followed by Zn(II), Cr(VI), Mn(II), Cd(II), Ni(II) and Pb(II). The adsorption of Cu(II) was found to be dependent on initial concentration of solution, pH, adsorbent dose, temperature and contact time. The adsorption followed pseudo-first-order and second-order kinetics but pseudo-second-order kinetic model was better obeyed since experimental data agreed well with theoretical data. Thermodynamic parameters were also evaluated. The adsorption process was found to be endothermic and spontaneous in nature. Attempts were also made to desorb Cu(II) from the adsorbent and regeneration of the spent adsorbent. The breakthrough and exhaustive capacities were found to be 5 and 10 mg g⁻¹, respectively.

Keywords: Adsorbent, Adsorbent Dose, Adsorption, Adsorption Behavior, Aqueous Solution, Behavior, Breakthrough, Breakthrough Capacity, Cd(II), Concentration, Copper, Copper(II), Cr(VI), Cu(II), Data, Endothermic, Experimental, Heavy Metals, Kinetic, Kinetic Model, Kinetics, Metals, Model, Mustard Oil Cake, Ni(II), Pb(II), pH, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Regeneration, Second Order, Second Order Kinetics, Second-Order, Second-Order Kinetics, Solution, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Zn(II)

? Andreozzi, R., Canterino, M., Marotta, R. and Paxeus, N. (2005), Antibiotic removal from wastewaters: The ozonation of amoxicillin. Journal of Hazardous Materials, 122 (3), 243-250.

Full Text: J\J Haz Mat122, 243.pdf

Abstract: The presence of amoxicillin, a widely used antibiotic, has been documented in Sewage Treatment Plant (STP) effluents. As for other pharmaceuticals, ozonation is proposed as a process for its abatement from these effluents. The results of ozonation experiments on amoxicillin-containing aqueous solutions indicate that ozone attack is mainly directed towards the phenolic ring of the studied molecule leading to the formation of hydroxyderivative intermediates. No direct evidences of attack on sulfur atom with sulfoxide formation are found. A kinetic investigation is carried out allowing the assessment of the kinetics of direct ozone attack and that of OH radicals to amoxicillin.

Keywords: Amoxicillin, Sewage Treatment Plant Effluents, Ozonation Experiments

? Ötker H.M. and Akmehmet-Balcıoğlu, I. (2005), Adsorption and degradation of enrofloxacin, a veterinary antibiotic on natural zeolite. Journal of Hazardous Materials, 122 (3), 251-258.

Full Text: J\J Haz Mat122, 251.pdf

Abstract: The adsorption of enrofloxacin, a veterinary antibiotic onto natural zeolite and further decontamination of zeolite was investigated in the present study. In the first part of the study, the effects of pH, temperature, and presence of ammonium ion on the adsorption process were examined and evaluated on the basis of Langmuir and Freundlich isotherms. Adsorption of enrofloxacin on natural zeolite was found to be highly pH dependent, exhibiting increases correspondent to decreases in pH. The positive value of enthalpy change showed the endothermic nature of adsorption processes. The presence of ammonium ion enhanced the adsorption of enrofloxacin. In the second part of the study, infrared (IR) spectroscopy, and scanning electron microscopy (SEM) were used for the determination of the modifications on the zeolite surfaces resulting from adsorption and ozone treatment. It was found that ozone at sufficient concentrations over specified time periods was able to decompose the enrofloxacin adsorbed on zeolite.

Keywords: Adsorption, Veterinary Antibiotic, Enrofloxacin, Zeolite, Ozonation, Manure

? Namasivayam, C. and Prathap, K. (2005), Recycling Fe(III)/Cr(III) hydroxide, an industrial solid waste for the removal of phosphate from water. Journal of Hazardous Materials, 123 (1-3), 127-134.

Full Text: J\J Haz Mat123, 127.pdf

Abstract: Industrial solid waste, Fe(III)/Cr(III) hydroxide, was investigated to assess the capacity for the removal of phosphate from aqueous solution. Langmuir and Freundlich isotherms were used to model the adsorption equilibrium data. The system follows both isotherms. Adsorption capacity was found to be 6.5 mg/g. Kinetic studies show that the adsorption obeyed second order kinetics. Thermodynamic parameters were evaluated. Overall adsorption process was endothermic and spontaneous. Optimum pH for phosphate adsorption was found to be 4.0. Effect of coexisting anions has also been examined.

Keywords: Phosphate, Adsorption, Fe(III)/Cr(III) Hydroxide, Kinetics, Isotherms, pH Effect, Temperature, Foreign Ions

? Taty-Costodes, V.C., Fauduet, H., Porte, C. and Ho, Y.S. (2005), Removal of Lead(II) ions from synthetic and real effluents using immobilized Pinus sylvestris sawdust: Adsorption on a fixed-bed column. Journal of Hazardous Materials, 123 (1-3), 135-144.

Full Text: 2005\J Haz Mat123, 135.pdf; J\J Haz Mat-Taty.pdf

Abstract: The purpose of this work was to evaluate the potential of Pinus sylvestris sawdust, in a continuous flow removal of Lead(II) ions from synthetic and industrial aqueous effluents. The kinetic parameters obtained in a batch process were used to scale-up the process on a mini-column and to choose the breakthrough model. The column experimental data concerning the volumes treated were correlated using the bed depth service time model. These experimental data closely fitted the bed depth service time model at 10% of the breakthrough curve.

The results from the bed depth service time model on the mini-column were then used to design a pilot plant adsorption unit. The performance of the pilot plant column accurately agreed with that obtained from the mini-column. The experiments carried out in a dynamic reactor allowed to bring out the influence of various parameters on the efficiency of the P. sylvestris sawdust. In addition, the process was checked for the treatment of industrial aqueous effluents on a pilot plant scale and the results were in accordance with those obtained from synthetic effluents.

Keywords: Adsorption, Lead, Sawdust, Pilot Plant, Bed Depth Service Time, Biosorption, Diffusion, Water, Model, Pore

? Dursun, A.Y. and Kalayci, Ç.S. (2005), Equilibrium, kinetic and thermodynamic studies on the adsorption of phenol onto chitin. Journal of Hazardous Materials, 123 (1-3), 151-157.

Full Text: J\J Haz Mat123, 151.pdf

Abstract: The adsorption of phenol onto chitin, a naturally occurring material was studied as a function of initial pH, temperature and initial phenol concentration. The highest phenol adsorption capacity was determined as 21.5 mg g⁻¹ for 300 mg dm⁻³ initial phenol concentration at pH 1.0 and 40 °C. Adsorption data were well described by the Freundlich Model, although they could be modeled by the Langmuir equation. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data. The pseudo-second-order kinetic model provided the best correlation of the experimental data compared to the pseudo-first-order model. The thermodynamic constants of the adsorption process; ΔG°, ΔH° and ΔS° were evaluated as –19.4 kJ mol⁻¹ (at 40 °C), 10.2 kJ mol⁻¹ and 0.093 kJ mol⁻¹ K⁻¹, respectively. These showed that adsorption of phenol on chitin was endothermic and spontaneous.

Keywords: Adsorption, Adsorption Capacity, Capacity, Chitin, Concentration, Correlation, Data, Endothermic, Equilibrium, Experimental, Freundlich, Function, Kinetic, Kinetic Model, Kinetic Models, Langmuir, Langmuir Equation, Model, Models, pH, Phenol, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Temperature, Thermodynamic, Thermodynamic Studies, Thermodynamics

? Ahmadi, M., Vahabzadeh, F., Bonakdarpour, B., Mofarrah, E. and Mehranian, M. (2005), Application of the central composite design and response surface methodology to the advanced treatment of olive oil processing wastewater using Fenton’s peroxidation. Journal of Hazardous Materials, 123 (1-3), 187-195.

Full Text: 2005\J Haz Mat123, 187.pdf

Abstract: The central composite design (CCD) technique was used to study the effect of the Fenton’s peroxidation on the removal of organic pollutants from olive oil mill wastewater (OMW). The ratio of hydrogen peroxide-to-Fe(II) (x(1)) was between 1.67 and 8.33. Fe(II) concentration was constant at 0.03 M while the H₂O₂ concentration was set at three levels: 0.05, 0.15 and 0.25 M. Based on the molarity ratio, the selected ratio were in the low range of Fe(II)-to-H₂O₂ ratio (<< 1). While based on the wt/wt ratio, the tested Fe(II)-to-H₂O₂ ratios were in the range of <= 1:5. pH (x(2)) was between 3 and 5. The concentration of OMW (x(3)) was varied between 40 and 100%. The influence of these three independent variables on the four dependent variables, i.e. COD, total phenolics (TP), color and aromatocity removal was evaluated using a second-order polynomial multiple regression model. Analysis of variance (ANOVA) showed a high coefficient of determination (R 2) value of 0.902-0.998, thus ensuring a satisfactory adjustment of the second-order regression model with the experimental data. H₂O₂-to-Fe(II) ratio had significant effect on all the four dependent variables. The positive sign for the regression coefficient of this regressor variable indicated that the level of the pollutant removal increased with the increased levels of factor x, from 1.67 to 8.33 and this effect was the most pronounced for TP removal. pH had also significant effect on the pollutant removal and the effect was the most noticeable for TP reduction. The negative coefficient of this variable (pH) indicated that level of the pollutant removal decreased as the pH increased from 3 to 5. The negative coefficient of the interaction between variable x(1) and x(2) indicated that a simultaneous increase in H₂O₂-to-Fe(II) ratio with decrease in the pH of the reaction led to an increase in the COD, TP and color removal. Quadratic models were predicted for the response variable, i.e. pollutant removal, and the maximum model-predicted removals were 56, 100, 33 and 32% for COD, TP, color and aromatocity, respectively. Optimum conditions for this wastewater treatment was obtained based on the performance of the Fenton’s peroxidation in the experiment where the H₂O₂-to-Fe(II) ratio was at its high level (8.33) and the pH and OMW concentration were 4 and 70%, respectively. (c) 2005 Elsevier B.V. All rights reserved.

Keywords: Advanced Oxidation Process, Central Composite Design, Empirical Modeling, Fenton’s Peroxidation, Olive Oil Mill Wastewater, Response Surface Methodology, Biological Processes, Oxidation Processes, Reagent, Wastewaters, Phenol, Biodegradation, Optimization, Substances, Acid

? Khezami, L. and Capart, R. (2005), Removal of chromium(VI) from aqueous solution by activated carbons: Kinetic and equilibrium studies. Journal of Hazardous Materials, 123 (1-3), 223-231.

Full Text: J\J Haz Mat123, 223.pdf

Abstract: The objective of this study is to assess the uptake of hexavalent chromium (Cr(VI)) from aqueous solutions onto activated carbons (AC) produced from wood. Two activated carbons are tested, a KOH-activated carbon and a commercial H₃PO₄-activated carbon (Acticarbone CXV). The adsorption of Cr(VI) is maximal at the lowest values of pH (pH 3) and increases with temperature for both adsorbents. The KOH-activated carbon shows higher capacity for adsorption of Cr(VI) than Acticarbone. The sorption isotherms fit the Langmuir model accurately. The adsorption reaction was found to obey a pseudo second-order rate. The activation energy and the pre-exponential factor as well as the thermodynamic functions related to adsorption reaction, ΔS°, ΔH°, ΔG°, were determined. Nevertheless, the global reaction rate is probably controlled by the intra-particular diffusion of Cr(VI) and the mass diffusivity of Cr(VI) was evaluated.

Keywords: Activated Carbon, Activated Carbons, Activation, Activation Energy, Adsorbents, Adsorption, Aqueous Solution, Aqueous Solutions, Capacity, Carbon, Chromium, Chromium(VI), Cr(VI), Diffusion, Energy, Equilibrium, Equilibrium Studies, Functions, Hexavalent Chromium, Isotherms, Kinetic, Kinetics, Langmuir, Langmuir Model, Model, pH, Pseudo Second Order, Pseudo Second-Order, Pseudo-Second-Order, Removal, Second Order, Second-Order, Solution, Solutions, Sorption, Sorption Isotherms, Temperature, Thermodynamic, Thermodynamics, Uptake, Wood

? Lenoble, V., Laclautre, C., Deluchat, V., Serpaud, B. and Bollinger, J.C. (2005), Arsenic removal by adsorption on iron(III) phosphate. Journal of Hazardous Materials, 123 (1-3), 262-268.

Full Text: J\J Haz Mat123, 262.pdf

Abstract: Under natural conditions, arsenic is often associated with iron oxides and iron(III) oxidative capacity towards As(III) is well known. In this study, As(III) and As(V) removal was performed using synthesised iron(III) phosphate, either amorphous or crystalline. This solid can combine (i) As(III) oxidation by iron(III) and (II) phosphate substitution by As(V) due to their similar properties. Results showed that adsorption capacities were higher towards As(III), leading to Fe²⁺ and HAsO₄²⁻ leaching. Solid dissolution and phosphate/arsenate exchange led to the presence of Fe³⁺ and PO₄³⁻ in solution, therefore various precipitates involving As(V) can be produced: with Fe²⁺ as Fe₃(AsO₄)₂·8H₂O_(s) and with Fe³⁺ as FeAsO₄·2H₂O_(s). Such formations have been assessed by thermodynamic calculations. This sorbent can be a potential candidate for industrial waste treatment, although the high release of phosphate and iron will exclude its application in drinking water plants.

Keywords: Arsenic, Adsorption, Iron(III) Phosphate

? Kumar, K.V. and Sivanesan, S. (2005), Comparison of linear and non-linear method in estimating the sorption isotherm parameters for safranin onto activated carbon. Journal of Hazardous Materials, 123 (1-3), 288-292.

Full Text: J\J Haz Mat123, 288.pdf

Abstract: Comparison analysis of linear least square method and non-linear method for estimating the isotherm parameters was made using the experimental equilibrium data of safranin onto activated carbon at two different solution temperatures 305 and 313 K. Equilibrium data were fitted to Freundlich, Langmuir and Redlich–Peterson isotherm equations. All the three isotherm equations showed a better fit to the experimental equilibrium data. The results showed that non-linear method could be a better way to obtain the isotherm parameters. Redlich–Peterson isotherm is a special case of Langmuir isotherm when the Redlich–Peterson isotherm constant g was unity.

Keywords: Activated Carbon, Analysis, Aqueous-Solution, Carbon, Copper, Data, Dye Adsorption, Dyestuffs, Equilibrium, Equilibrium Isotherm, Experimental, Freundlich, Ions, Isotherm, Isotherm Equations, Isotherm Parameters, Kinetics, Langmuir, Langmuir Isotherm, Linear Method, Non-Linear Method, Peat, Redlich-Peterson, Removal, Rights, Safranin, Solution, Sorption, Sorption Isotherm, Tree Fern

? Tuprakay, S. and Liengcharensit, W. (2005), Lifetime and regeneration of immobilized titania for photocatalytic removal of aqueous hexavalent chromium. Journal of Hazardous Materials, 124 (1-3), 53-58.

Full Text: 2005\J Haz Mat124, 53.pdf

Abstract: Immobilized titania (TiO2) batch reactors reduced hexavalent chromium (Cr(VI)) in the form of potassium dichromate (K2Cr2O7) to trivalent chromium (Cr(III)) in aqueous solution at pH 3 under 171 W/m(2) light intensity. The light source was a 125-W ultraviolet (UV) lamp. The Cr(VI) reduction showed zero-order kinetics (k(0)), while the Cr(VI) adsorption fitted with first-order kinetics (k(1st)). Adsorption capacity increased with increasing initial Cr(VI) concentration, and the area of immobilized TiO2 limited the reduction efficiency. The lifetime of fresh immobilized TiO2 was approximately 14 h. In addition, the regeneration of TiO2 with 3 M sodium hydroxide (NaOH) was necessary to improve adsorption reaction. (c) 2005 Elsevier B.V All rights reserved.

Keywords: Adsorption, Adsorption Capacity, Aqueous Solution, Capacity, Catalytic-Activity, Chromium, Cr(VI), Cr(VI), Cr(VI) Adsorption, Cr(VI) Reduction, Degradation, Dioxide, First Order, Hexavalent, Hexavalent Chromium, Immobilized, Immobilized Titania, Kinetics, Lifetime, Metal-Ions, NaOH, pH, Photocatalytic, Potassium, Reactor, Reduction, Regeneration, Removal, Systems, TiO₂, Trivalent Chromium, Water

? Pan, B.C., Meng, F.W., Chen, X.Q., Pan, B.J., Li, X.T., Zhang, W.M., Zhang, X., Chen, J.L., Zhang, Q.X. and Sun, Y. (2005), Application of an effective method in predicting breakthrough curves of fixed-bed adsorption onto resin adsorbent. Journal of Hazardous Materials, 124 (1-3), 74-80.

Full Text: 2005\J Haz Mat124, 74.pdf

Abstract: Removal of many organic pollutants including phenolic compounds from industrial wastewater can always be achieved by fixed-bed adsorption onto the polymeric resin adsorbent, and the relevant breakthrough curves would provide much valuable information to help to design a fixed-bed adsorption process in field application. In the present study, a model developed based on the constant-pattern wave approach theory and the Freundlich model was adopted to describe the breakthrough curves of phenol and p-nitrophenol adsorption onto a macroreticular resin adsorbent NDA-100 from aqueous solution. Column experiments were performed at different conditions to verify the model and the results proved that the model would describe the breakthrough curves well. Effect of the operation parameters on breakthrough curves was also discussed to get helpful information in choosing the adsorption process.

Keywords: Phenol, Fixed-Bed Adsorption, Breakthrough Curve, Mathematical Model, Resin Adsorbent

? Ayranci, E. and Duman, O. (2005), Adsorption behaviors of some phenolic compounds onto high specific area activated carbon cloth. Journal of Hazardous Materials, 124 (1-3), 125-132.

Full Text: 2005\J Haz Mat124, 125.pdf

Abstract: Adsorption of phenol, hydroquinone, m-cresol, p-cresol and p-nitrophenol from aqueous solutions onto high specific area activated carbon cloth has been studied. The effect of ionization on adsorption of these ionizable phenolic compounds was examined by studying the adsorption from acidic, basic and natural pH solutions. Kinetics of adsorption was followed by in situ UV spectroscopy over a period of 90 min. First-order rate law was found to be valid for the kinetics of adsorption processes and the rate constants were determined. The highest rate constants were obtained for the adsorption from solutions at the natural pH. The lowest rate constants were observed in basic solutions. The rate constants decreased in the order p-nitrophenol  m-cresol > p-cresol > hydroquinone  phenol. Adsorption isotherms were derived at 30 °C and the isotherm data were treated according to Langmuir, Freundlich and Tempkin isotherm equations. The goodness of fit of experimental data to these isotherm equations was tested and the parameters of equations were determined. The possible interactions of compounds with the carbon surface were discussed considering the charge of the surface and the possible ionization of compounds at acidic, basic and natural pH conditions.

Keywords: Activated Carbon Cloth, Adsorption, Phenolic Compounds, Spectrophotometry

? Cai, J.G., Li, A.M., Shi, H.Y., Fei, Z.H., Long, C. and Zhang, Q.X. (2005), Adsorption characteristics of aniline and 4-methylaniline onto bifunctional polymeric adsorbent modified by sulfonic groups. Journal of Hazardous Materials, 124 (1-3), 173-180.

Full Text: 2005\J Haz Mat124, 173.pdf

Abstract: In this paper a new bifunctional polymeric resin (LS-2) was synthesized by introducing sulfonic groups onto the surface of the resin during the post-crossing of chloromethyl low crosslinking macroporous poly-styrene resin, and the comparison of the adsorption properties of LS-2 with Amberlite XAD-4 toward aniline and 4-methylaniline in aqueous solutions was made. The study focuses on the static equilibrium adsorption behaviors, the adsorption thermodynamics, and the column dynamic adsorption and desorption profiles. Freundlich model gives a perfect fitting to the isotherm data. Although the specific surface area of LS-2 is lower than that of Amberlite XAD-4, the adsorbing capacities for these two adsorbates on LS-2 are higher than those on Amberlite XAD-4 within the temperature range 288-318 K, which is contributed to microporous structure and the polar groups on the network of LS-2 resins. The adsorption for aniline or 4-methylaniline on LS-2 was proved to be an endothermic process and increasing temperature was favorable. From the studies on the adsorption thermodynamics, static equilibrium adsorption, and the desorption conditions, an important conclusion can be drawn that the adsorption for aniline or 4-methylaniline on the LS-2 is a coexistence process of physical adsorption and chemical transition. (c) 2005 Elsevier B.V. All rights reserved.

Keywords: 4-Methylaniline, Adsorption, Adsorption Properties, Aniline, Aqueous-Solutions, Bifunctional Polymeric Adsorbent, Biodegradation, Carbon, Chemical, Crosslinking, Desorption, Equilibrium, Hypercrosslinked Adsorbent, Hypercrosslinked Polystyrene, Isotherm, Made, Microporous, Model, Modified, Paper, Phenolic-Compounds, Physical Adsorption, Polymeric, Polystyrene, Profiles, Properties, Range, Removal, Resins, Sorbents, Specific Surface Area, Structure, Sulfonic Groups, Surface, Surface Area, Temperature, Thermodynamics

? Rozada, F., Otero, A., Morán, A. and García, A.I. (2005), Activated carbons from sewage sludge and discarded tyres: Production and optimization. Journal of Hazardous Materials,