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Application of fly ash and activated carbon in the removal of Cu(2+) and Ni(2+) ions from aqueous solutions
(TAYLOR & FRANCIS INC, 2008) Pehlivan, E.; Cetin, S.
The main objective of this study was to remove Cu(2+) and Ni(2+) ions from aqueous solution by using fly ash, an industrial solid waste of the sugar industry and commercial activated carbon at equilibrium, which follows Langmuir and Freundlich adsorption isotherms. In order to identify influential parameters and to evaluate their interactions, effects of time, pH, initial metal concentration, and amount of adsorbent were studied, and the results were compared with those of activated carbon under the same experimental conditions. Adsorption studies were performed in a time interval (1-240 min), at various pH values (2.0-8.0) at 25 degrees C and at metal concentrations of 1-10 x 1(-4) M using different amounts of adsorbent (1-12 g/L). The equilibrium time was fixed at 60 min in the case of Cu(2+) and Ni(2+), and 8 g/L of fly ash and 6 g/L activated carbon was sufficient for the optimum removal of both the metal ions. The sorption of metal ions increased with an increase of pH, and maximum removal was obtained at 5.0 for fly ash with 97.2% and 78.2% removal for Cu(2+) and Ni(2+) ions, respectively. For AC, on the other hand, maximum removal was obtained at 4.0 for Cu(2+) and 6.0 for Ni(2+) with 95.0% and 63.0% removal, respectively. The adsorption capacities are 7.0 mg/g for Cu(2+), 5.9 mg/g for Ni(2+) for fly ash, and 6.9 mg/g for Cu(2+), 5.4 mg/g for Ni(2+) for activated carbon. The orders of adsorption of heavy metal ions for fly ash and activated carbon change in the order of Cu(2+) Ni(2+) and Cu(2+) Ni(2+), respectively. The fly ash was found to be a metal adsorbent as effective as commercial activated carbon.
Batch Sorption of Divalent Metal Ions Onto Brown Coal
(Taylor & Francis Inc, 2006) Pehlivan, E.; Gode, F.
Brown coal, a relatively abundant and inexpensive material is currently being investigated as an adsorbent to remove some contaminants from aqueous solution. The adsorption of some heavy metals from aqueous solutions on the brown coals was studied as a function of pH, contact time, adsorbent dosage and concentration of metal solutions. A carboxyl, phenolic hydroxyl, and metoxyl functional group present on the coal surface was the adsorption site to remove metal ions from solution by means of ion exchange and hydrogen bonding. Effective removal of heavy metals was achieved at pH values of 4.0-5.0. The experimental data have been analyzed using the Langmuir on isotherm models. Under optimized conditions, the percentage of metal removal by brown coal adsorption was over 80%.
The Effect of Ph and Temperature on the Sorption of Zinc(Ii), Cadmium(Ii), and Aluminum(Iii) Onto New Metal-Ligand Complexes of Sporopollenin
(ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS, 1995) Pehlivan, E.; Ersöz, M.; Pehlivan, M.; Yıldız, S.; Duncan, H. J.
Sorption of metal ions from aqueous solution onto metal-ligand complexes of sporopollenin derivatives has been measured as a function of pH at several temperatures between 20 and 50 degrees C, Novel metal-ligand exchange resins possessing oxime and carboxylic acid sidearm functionality were prepared through the reaction of diaminosporopollenin with dichloro-antiglyoxime and bromoacetic acid, The pH dependencies and sorption isotherms of various metal ions such as Zn(II), Cd(II), and AI(III) on the resin were investigated from aqueous solution, The sorption behavior of these metal-ligand complexes of sporopollenin derivatives and the possibilities of selectively removing and recovering heavy metals are explained on the basis of their chemical nature and complex properties and the results are interpreted in terms of the variations of pH. (C) 1995 Academic Press, Inc.
Equilibrium isotherm studies for the uptake of cadmium and lead ions onto sugar beet pulp
(ELSEVIER SCI LTD, 2008) Pehlivan, E.; Yanik, B. H.; Ahmetli, Gülnare; Pehlivan, M.
The adsorption of Cd2+ and Pb2+ on sugar beet pulp (SBP), a low-cost material, has been studied. In the present work, the abilities of native (SBP) to remove cadmium (Cd2+) and lead (Pb2+) ions from aqueous solutions were compared. The (SBP) an industrial by product and solid waste of sugar industry were used for the removal of Cd2+ and Pb2+ ions from aqueous water. Batch adsorption studies were carried out to examine the influence of various parameters such as initial pH, adsorbent dose, initial metal ion concentration, and time on uptake. The sorption process was relatively fast and equilibrium was reached after about 70 min of contact. As much as 70-75% removal of Cd2+ and Pb2+ ions for (SBP) are possible in about 70 min, respectively, under the batch test conditions. Uptake of Cd2+ and Pb2+ ions on (SBP) showed a pH-dependent profile. The overall uptake for the (SBP) is at a maximum at pH 5.3 and gives up to 46.1 mg g(-1) for Cd2+ and at pH 5.0 and gives 43.5 mg g(-1) for Pb2+ for (SBP), which seems to be removed exclusively by ion exchange, physical sorption and chelation. A dose of 8 g L-1 was sufficient for the optimum removal of both the metal ions. The Freundlich represented the sorption data for (SBP). In the presence of 0.1 M NaNO3 the level of metal ion uptake was found to reach its maximum value very rapidly with the speed increasing both with the (SPB) concentration and with increasing initial pH of the suspension. The reversibility of the process was investigated. The desorption of Cd2+ and Pb2+ ions which were previously deposited on the (SBP) back into the deionised water was observed only in acidic pH values during one day study period and was generally rather low. The extent of adsorption for both metals increased along with an increase of the (SBP) dosage. (SBP), which is cheap and highly selective, therefore seems to be a promising substrate to entrap heavy metals in aqueous solutions. (C) 2007 Elsevier Ltd. All rights reserved.
Equilibrium Studies for the Sorption of Zinc and Copper From Aqueous Solutions Using Sugar Beet Pulp and Fly Ash
(Elsevier Science Bv, 2006) Pehlivan, E.; Çetin, S.; Yanık, B. H.
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 the presence of low ionic strength or low concentration of Na and Cl ions does not have that the monolayer sorption. mainly due to ion exchange 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.
In-field measurements of PCDF emissions from coal combustion and their quantitative analyses
(TAYLOR & FRANCIS INC, 2008) Pehlivan, M.; Beduek, D.; Pehlivan, E.
In this study, a series of polychlorinated dibenzofurans (PCDFs) emitted to the surrounding soil as the result of the combustion of coal and wood from the industrial steam boilers and household stoves have been identified. Levels of polychlorinated dibenzofurans (PCDF) in soil samples were measured at different sites in proximity to the municipal solid waste incinerator (MSWI) to determine baseline contamination and the contributory role of incinerator emissions. PCDF contaminants were concentrated from soil samples and isolated from other materials by chromatographic methods. PCDF isomers were identified separately by column chromatography utilizing column packed with materials such as Kieselgel/44 vol% H(2)SO(4), Macro Alumina B Super 1, Mix. Column, Bio Beads S-X3 Gel Chromatography, Min Alumina B Super 1 + Kieselgel/AgNO(3) and their quantitative determinations were performed by GC/MS (gas chromatography/mass spectroscopy). The PCDF levels were subsequently compared with established values from previous studies.
Ion-Exchange Equilibria of Heavy-metals in Aqueous-solution on New Chelating Resins of Sporopollenin
(ELSEVIER SCIENCE BV, 1995) Ersöz, M.; Pehlivan, E.; Duncan, H.J.; Yıldız, S.; Pehlivan, M.
Studies have been conducted on the sorption of several heavy metal ions Cu(II), Ni(II), Zn(II), Cd(II) and AI(III) from aqueous solutions on the new chelating exchangers of sporopollenin (Lycopodium clavatum) as a function of pH at several temperatures between 20 and 50 degrees C. The novel metal-ligand exchange resins possessing oxime and carboxylic acid side arm functionality were prepared through the reaction of diaminosporopollenin with dichloroantiglyoxime and bromoacetic acid. The sorption of all metals increased considerably in the range of pH 6-10 and was observed in sequence as: Cu greater than or equal to Ni > Zn > Cd > Al for carboxylated-diaminoethyl-sporopollenin (DAEC) and Ni greater than or equal to Cu > Zn > Cd > Al for bis-diaminoethyl-glyoxime-sporopollenin (bDAEG). The level of pH of the aqueous medium had a large influence on the sorption capacity, and the uptake of metals, except Al(III), was found to be 90% or more. The metal-form resins afforded complete recovery of the sorbed species by acid stripping. Both resins also showed high stability towards concentrated acids and bases and retained their high capacity for heavy metals.
Ligand Sorption Kinetics of Aromatic-amines on New Ligand-exchanger Sporopollenin in Cobalt Ion Form
(JOHN WILEY & SONS INC, 1995) Vural, U.S.; Ersöz, M.; Pehlivan, E.
An approach to study of intraparticle ion-exchange kinetics of aromatic amines such as p-chloroaniline, p-toluidine, and p-nitroaniline as ligands on Co2+ loaded-ligand exchanger of sporopollenin (carboxylated epichlorohydrine [CEP]-sporopollenin) is presented and the ligand-exchange reaction in the resin matrix is shown to be rate-determining, Kinetic studies of aromatic amines as ligands on the CEP-sporopollenin have been performed using continuous column runs. The observed rate seems to be related to the rate of ligand sorption with the mobile phase (ion) and pH in the aqueous phase. The rate of attainment of equilibrium sorption and breakthrough curves of aromatic amines is seen to be nearly similar. With the sorption mechanism deduced to be dominantly particle diffusion-controlled diffusion coefficients determined were found to range from 1.10(-8) to 1.0 10(-9) cm(2) s(-1). Coupled with the fact that different concentrations of solution were employed, these results may be interpreted as indicating that particle diffusion is the rate-determining step; on the contrary, film diffusion was not a rate-controlling step in the ligand-sorption process under the conditions employed. (C) 1995 John Wiley & Sons, Inc.
Ligand-exchange Chromatography of Nucleosides, Nucleic-Acid Bases and Amines on Copper(Ii) Glyoximated-Lycopodium Clavatum With Refractive-İndex Detection
(MARCEL DEKKER INC, 1989) Ersöz, M.; Pehlivan, E.; Yıldız, S.
Ligand-exchange separation of nucleosides, nucleic acid bases and amines has been studied by using a new exchanger ob- tained by functionalyzing Lycopodium Clavatum with glyoxime. This study shows that ligand-exchange chromatography with glyoximated-lycopodium clavatum can provide new opportunities for the rapid separation of ligands.
Ligand-exchange Chromatography of Some Amino-acids on Co(Ii)-loaded Cmdae-sporopollenin Resin
(MARCEL DEKKER INC, 1995) Ayar, A.; Yıldız, S.; Pehlivan, E.
Sporopollenin obtained from Lycopodium clavatum has been modified as an ligand-exchange material. In this study, the possibility of using sporopollenin as a ligand exchanger in the chromatographic separation of amino acids is examined. Since sporopollenin has important advantages (it is stable to chemicals and has a constant mesh size), it can be used as a column packing material. By first treating sporopollenin with 1,2-diaminoethane and then with bromoacetic acid, carboxylated diaminoethylsporopollenin (CMDAE-sporopollenin) was obtained. This new resin was loaded with Co(II) transition element and used as a ligand-exchange material in the separation of amino acids. Using the ligand-exchange technique on Co(II)-loaded carboxylated diaminoethylsporopollenin is a suitable chromatographic method for the separation of most common amino acids.
Modified Sporopollenin as a Novel Anion, Cation and Ligand-Exchange Medium
(MARCEL DEKKER INC, 1988) Pehlivan, E.; Yıldız, S.
Ion-exchange and ligand-exchange chromatography with the modified sporopollenin is a useful technique for the rapid separation of nucleosides, nucleotides, amino acids, amines and transit ion el emen ts . The sporopollenin has been modified for use as anion-, cation- and ligand-exchanger; diaminosporopollenin being the anion- exchanger form, sulphonated sporopollenin the cationexchanger form and carboxylated sporopollenin the ligand exchanger form. Sporopollenin was aminated by the trcatment with 1,: diruiiinothane for separation of nucleotides by anion-exchange; treatment with chlorosulphonic acid gave sulphonated sporopollenin for separation of amino acids by cation-exchange and treatment with brornoacetic acid gave carboxylated diaminosporopollenin for separation of nucleotides, nucleosides, amines and transition elements.
Physical and Chemical Factors Affecting the Adsorption of Cr(VI) via Humic Acids Extracted From Brown Coals
(Elsevier Science Bv, 2010) Arslan, Gülşin; Edebali, Serpil; Pehlivan, E.
The aim of this study is to demonstrate the potential of humic acids (HAs) as a low-cost reactive barrier material for environmental protection applications of toxic Cr(VI). Sorption of Cr(VI) on the HAs obtained from Ilgin, Beysehir and Ermenek lignites in Turkey were investigated and their sorption properties were compared with the activated carbon (AC) from Merck. The adsorption was carried out using a batch method. The sorption of Cr(VI) on the surface of HAs depends strongly on the pH and Cr(VI) sorption increased with a decreasing pH and increase in the concentration of this metal. The Freundlich adsorption isotherm was used to describe observed sorption phenomena. It was observed that the maximum adsorption capacity of 0.55 mmol Cr(VI)/g for Ilgin, 0.64 mmol Cr(VI)/g for Beysehir and 0.40 mmol Cr(VI)/g for Ermenek was achieved at pH of 3.2. The rise in temperature caused a slight decrease in the value of the equilibrium constant (K(c)) for the sorption of Cr(VI). The Cr(VI) sorption capacities of Beysehir and Ilgin HAs were nearly as same as that of AC (0.58 mmol Cr(VI)/g). Therefore, HAs are used for the adsorption of Cr(VI) in wastewater treatment applications.
Removal of As(V) from aqueous solutions by iron coated rice husk
(ELSEVIER, 2013) Pehlivan, E.; Tran, T. H.; Ouedraogo, W. K. I.; Schmidt, C.; Zachmann, D.; Bahadir, M.
A lignocellulosic material extracted from rice husk (Oryza sativa), Vietnam, was modified as a new adsorbent for the removal of As(V) ions from aqueous solution. Iron was coated onto this adsorbent by hydrolization of ferric nitrate while adding an alkaline solution drop wise into the batch type reactor. The adsorption of As(V) ions from aqueous solution on coated rice husk was then studied at varying pH, As(V) concentrations, contact times, ionic strength, and adsorbent amounts. The minimum contact time to reach equilibrium is about 6 h. The adsorption of As(V) anions on the coated rice husk was found to be highly pH dependent due to Coulomb interactions between As(V) species in solution and positively charged surface groups RH-FeOOH, as well as formation of chelate complexes with naturally occurring carboxyl and carbonyl functional groups in the matrix. As(V) adsorption on Fe(III)-coated rice husk (RH-FeOOH) from aqueous solution was studied in the pH range 2-10. The main effects of pH on adsorption are estimated by considering both the behavior of As(V) ions (hydrolysis and hydroxide precipitation) and the effect of pH on coordination. A strong effect of pH was demonstrated at pH 4.0 with a maximum percentage for removal of As(V) ions 94%. Although both Langmuir and Freundlich isotherms have been used to characterize the adsorption of As(V), the Langmuir model fitted the equilibrium data better than Freundlich model and confirmed the surface homogeneity of adsorbent. The maximum adsorption capacity is determined as 2.5 mg/g of adsorbent at pH 4.0 for the Fe(III)-coated rice husk. It is concluded that initial As(V) concentration has an effect on the removal efficiency of RH-FeOOH. Higher adsorption of As(V) was observed at lower initial concentrations. RH-FeOOH as a low cost material is effective for the removal of As(V) ions and may become a valuable adsorbent to improve the ground water quality in Vietnam. (C) 2012 Elsevier B.V. All rights reserved.
Removal of Cu(II) and Ni(II) from aqueous solution by lignite-based humic acids
(TAYLOR & FRANCIS INC, 2007) Arslan, G.; Cetin, S.; Pehlivan, E.
The removals of Cu(II) and Ni(II) metal ions from an aqueous solution were investigated by using humic acids (HAs) in a batch arrangement. HAs were prepared by using alkaline extraction, following sedimentation and acidic precipitation from three Turkish lignites: Ilgin, Beysehir, and Ermenek. The interactions of Cu(II) and Ni(II) with solid HAs and influence of three parameters (initial metal concentration, solution pH and temperature) on the removal of metals were studied. Adsorption equilibrium was achieved in about 120 min for Cu(II) and Ni(II) ions. The sorption of Cu( II) and Ni(II) on the surface of HAs depended strongly on the pH, and increased with increasing of pH and the initial concentration of metal. The sorption of Cu(II) was higher than that of Ni(II) for HAs. The equilibrium relationship between adsorbent and adsorbate is described by adsorption isotherms at a fixed temperature 35 degrees C, at pH similar to 4.0. The Langmuir adsorption isotherm was used to describe observed sorption phenomena. It was observed that the maximum adsorption capacity of Cu(II)/g was 0.27 mmol for Ilgin (HA(1)) and Beysehir (HA(2)), 0.19 mmol for Ermenek (HA(3)) and that of Ni(II)/g was 0.28 mmol for HA(1), 0.24 mmol for HA(2), 0.18 mmol for HA(3) at pH 4.1, respectively. More than 80% of Cu(II) was removed by HA(1) and HA(2) and 58% by HA(3), 82% of Ni( II) was removed by HA(1), 71% by HA(2) and 52% by HA(3) from aqueous solution. The adsorption of Cu( II) and Ni( II) was higher between pH 4.1 and 5.1 for all HAs, and maximum sorption was observed at pH 4.1. The increase in temperature caused a slight decrease in the value of the equilibrium constant (Kc) for the sorption of metal ions. Adsorption isotherms and kinetics data of Cu( II) and Ni( II) ions removed by HAs are presented and discussed.
Removal of metal ions using lignite in aqueous solution - Low cost biosorbents
(ELSEVIER SCIENCE BV, 2007) Pehlivan, E.; Arslan, G.
Turkish lignite can be used as a new adsorption material for removing some toxic metals from aqueous solution. The adsorption of lignite (brown young coals) to remove copper (Cu2+), lead (Pb2+), and nickel (Ni2+) from aqueous solutions was studied as a function of pH, contact time, metal concentration and temperature. Adsorption equilibrium was achieved between 40 and 70 min for all studied cations except Pb2+, which is between 10 and 30 min. The adsorption capacities are 17.8 mg/g for Cu2+, 56.7 mg/g for Pb2+, 13.0 mg/g for Ni2+ for BC1 (Ilgin lignite) and 18.9 mg/g for Cu2+, 68.5 mg/g for Pb2+, 12.0 mg/g for Ni2+ for BC2 (Beysehir lignite) and 7.2 mg/g for Cu2+, 62.3 mg/g for Pb2+, 5.4 mg/g for Ni2+ for AC (activated carbon). More than 67% of studied cations were removed by BC1 and 60% BC2, respectively from aqueous solution in single step. Whereas about 30% of studied cations except Pb2+, which is 90%, were removed by activated carbon. Effective removal of metal ions was demonstrated at pH values of 3.8-5.5. The adsorption isotherms were measured at 20 degrees C, using adsorptive solutions at the optimum pH value to determine the adsorption capacity The Langmuir adsorption isotherm was used to describe observed sorption phenomena. The rise in temperature caused a slight decrease in the value of the equilibrium constant (K-c) for the sorption of metal ions. The mechanism for cations removal by the lignite includes ion exchange, complexation and sorption. The process is very efficient especially in the case of low concentrations of pollutants in aqueous solution, where common methods are either economically unfavorable or technically complicated. (C) 2006 Elsevier B.V. All rights reserved.
Separation, Collection and Transportation of Municipal Solid Waste - A Case Study in Turkey
(1999) Taner, Fadime; Aksan, Y.; Çakır, Ö.; Güven, Y.; Halisdemir, Bülent; Baydar, G.; Odabaşı, Emrah; Pehlivan, E.
Municipal solid waste (MSW) is a valuable ore which contains pure and recyclable components. The technology for separation of the MSW components MSWC from each other is very expensive. Main problem for MSWC is nonrecylables if it is mixed and put together in the same container. In this study which was supported by municipality (Yenisehir Municipality, Mersin) financially, a site was chosen for the separation of components at source. In the beginning, the education program has been applied in three categories to train the members who are responsible for dealing with the component at source. The components were tried to be classified according to their chemical structure and the (system) technology to reuse of the component. About 8 classes of MSW were categorized, separated from each other and stored in the bags and/or boxes that are different in colors. The project has been implemented for 195 days and it was determined that the components separated were recovered in about 90% by mass. This project was planned, implemented and extended for the solution of the problems arising from MSWC.
Sorption equilibrium of Cr(VI) ions on oak wood charcoal (Carbo Ligni) and charcoal ash as low-cost adsorbents
(ELSEVIER, 2011) Pehlivan, E.; Kahraman, H.; Pehlivan, E.
The aim of this study is to demonstrate the potential of oak wood charcoal (WC) and oak wood charcoal ash (WCA) as a low-cost adsorbent for environmental protection applications of Cr(VI) ion. The influence of contact time, solution pH, initial metal concentration, amount of adsorbent and ionic strength on the removal of Cr(VI) ion was studied. The adsorption of Cr(VI) with (WC) and (WCA) was investigated in a batch arrangement. The Cr(VI) ions sorbed onto the adsorbents were determined by a UV-Visible Spectrophotometer. The sorption of Cr(VI) on the adsorbent surface depends strongly on the pH and Cr(VI) ion-sorption increased with a decreasing pH until pH 2 and increase in the concentration of this metal in solution phase. The adsorption of Cr(VI) was higher between pH 2.0 and 2.5 for both adsorbents. The Freundlich adsorption isotherm was used to describe observed sorption phenomena. The maximum adsorption capacity of 30.10 mg of Cr(VI)/g for (WC) and 46.17 mg of Cr(VI)/g for (WCA) was obtained at pH of 2 and 2.5 respectively. (C) 2010 Elsevier B.V. All rights reserved.
Sorption of Cr(VI) ions on two Lewatit-anion exchange resins and their quantitative determination using UV-visible spectrophotometer
(ELSEVIER SCIENCE BV, 2009) Pehlivan, E.; Cetin, S.
The sorption of Cr(VI) from aqueous solutions with macroporous resins which contain quarternary amine groups (Lewatit MP 64 and Lewatit MP 500) was studied at varying Cr(VI) concentration, adsorbent dose. pH, contact time and temperature. Batch shaking sorption experiments were carried out to evaluate the performance of Lewatit MP 64 and Lewatit MP 500 anion exchange resins in the removal of Cr(VI) from aqueous solutions. The concentration of Cr(VI) in aqueous solution was determined by UV-visible spectrophotometer. The ion exchange process, which is dependent on pH, showed maximum removal of Cr(VI) in the pH range 3-7 for an initial Cr(VI) concentration of 1 x 10(-3) M. The optimum pH for Cr(VI) adsorption was found as 5.0 for Lewatit MP 64 and 6.0 for Lewatit MP 500. The maximum Cr(VI) adsorption at pH 5.0 is 0.40 and 0.41 mmol/g resin for Lewatit MP 64 and Lewatit MP 500 anion exchangers, respectively. The maximum chromium sorption occurred at approximately 60 min for Lewatit MP 64 and 75 min for Lewatit MP 500. The suitability of the Freundlich and Langmuir adsorption models was also investigated for each chromium-sorbent system. The uptake of Cr(VI) by the anion exchange resins was reversible and so it has good potential for the removal of Cr(VI) from aqueous solutions. Both ion exchangers had high bonding constants but Lewatit MP 500 showed stronger binding. The rise in the temperature caused a slight decrease in the value of the equilibrium constant (K(c)) for the sorption of Cr(VI) ion. (c) 2008 Elsevier B.V. All rights reserved.
Sugarcane bagasse treated with hydrous ferric oxide as a potential adsorbent for the removal of As(V) from aqueous solutions
(ELSEVIER SCI LTD, 2013) Pehlivan, E.; Tran, H. T.; Ouedraogo, W. K. I.; Schmidt, C.; Zachmann, D.; Bahadir, M.
The mechanism of As(V) removal from aqueous solutions by means of hydrated ferric oxide (HFO)-treated sugarcane bagasse (SCB-HFO) (Saccharum officinarum L.) was investigated. Effects of different parameters, such as pH value, initial arsenic concentration, adsorbent dosage, contact time and ionic strength, on the As(V) adsorption were studied. The adsorption capacity of SCB-HFO for As(V) was found to be 22.1 mg/g under optimum conditions of pH 4, contact time 3 h and temperature 22 degrees C. Initial As(V) concentration influenced the removal efficiency of SCB-HFO. The desorption of As(V) from the adsorbent was 17% when using 30% HCl and 85% with 1 M NaOH solution. FTIR analyses evidenced two potential binding sites associated with carboxyl and hydroxyl groups which are responsible for As(V) removal. Adsorption, surface precipitation, ion exchange and complexation can be suggested as mechanisms for the As(V) removal from the solution phase onto the surface of SCB-HFO. (C) 2012 Elsevier Ltd. All rights reserved.
Transport Studies of Amino-Acids Through a Liquid Membrane System Containing Carboxylated Poly(Styrene) Carrier
(ELSEVIER SCIENCE BV, 1995) Ersoz, M.; Vural, U. S.; Okdan, A.; Pehlivan, E.; Yıldız, S.
Transport mechanisms have been studied for amino acids such as p-amino benzoic acid and phenylalanine moving through a bulk organic liquid membrane system containing carboxylated poly( styrene) carrier. The transport in this system, in which one side of the membrane was acidic and the other side was alkaline, was influenced significantly by the initial H+ ion concentration on the acidic side. The passage of amino acids through the organic bulk liquid membrane was governed by an electrochemical interaction between carboxyl groups in the membrane and transporting materials.

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