Tamer Akar

Enhanced biosorption of nickel(II) ions by silica-gel-immobilized waste biomass : Biosorption characteristics in batch and dynamic flow mode

Batch and dynamic flow biosorption studies were carried out using the waste biomass entrapped in silica-gel matrix for the removal of nickel(II) ions from synthetic solutions and real wastewater. Batch biosorption conditions were examined with respect to initial pH, S/L ratio, contact time, and initial nickel ion concentration. Zeta potential measurements showed that immobilized biosorbent was negatively charged in the pH range of 3.0-8.0. The immobilized biomass was found to possess relatively high biosorption capacity (98.01 mg g(-1)), and biosorption equilibrium was established in a short time of operation (5 min). The equilibrium data were followed by Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. Scanning electron microscope analysis was used to screen the changes on the surface structure of the waste biomass after immobilization and nickel(II) biosorption. Sorbent-sorbate interactions were confirmed by Fourier transform infrared spectroscopy. The applicability of sorbent system was investigated in a continuous mode, and column studies were performed under different flow rate, column size, and biosorbent dosage. Also, the proposed sorbent system was successfully used to remove the nickel ions from industrial wastewater in dynamic flow treatment mode. The results showed that silica-immobilized waste biomass was a low-cost promising sorbent for sequester of nickel(II) ions from synthetic and real wastewater.

An attractive agro-industrial by-product in environmental cleanup: Dye biosorption potential of untreated olive pomace

This research deals with the evaluation of highly available and cost effective waste biomass of olive pomace for the removal of reactive textile dye, RR198 from aqueous medium and a real effluent. The experiments were conducted to assess the effects of process variables such as initial pH, biosorbent dosage, contact time, temperature and ionic strength. The results showed that the highest dye biosorption capacity was found at pH 2 and the needed time to reach the biosorption equilibrium was 40 min with a biosorbent concentration of 3.0 g L(-1). The sorption kinetics of dye was best described by the pseudo-second-order kinetic model. The equilibrium biosorption data were analyzed by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models and the results from the isotherm studies showed that the RR198 biosorption process occurred on a homogenous surface of the biosorbent. The waste biomass of olive oil industry displayed biosorption capacities ranging from 6.05 x 10(-5) to 1.08 x 10(-4)mol g(-1) at different temperatures. The negative values of Delta G degrees and the positive value of Delta H degrees suggest that the biosorption process for RR198 was spontaneous and endothermic. Dye-biosorbent interactions were examined by FTIR and SEM analysis. Finally, high biosorption yield of olive waste for the removal of RR198 dye from real wastewater makes it possible that the olive pomace could be applied widely in wastewater treatment as biosorbent taking into account that no pretreatment on the solid residue is carried out.

Investigation of the biosorption characteristics of lead(II) ions onto Symphoricarpus albus: Batch and dynamic flow studies

This work reports the results of the study for lead(II) binding by the natural and low cost biosorbent Symphoricarpus albus. Batch biosorption experiments demonstrated the high rate of lead(II) biosorption and the kinetic data were successfully described by a pseudo-second-order model. Biosorption of lead(II) onto S. albus biomass showed a pH-dependent profile and lead(II) biosorption was higher when pH or temperature was increased. As much as 88.5% removal of lead(II) is also possible in the multi-metal mixture. The Langmuir isotherm better fits the biosorption data and the monolayer biosorption capacity was 3.00 x 10(-4) mol g(-1) at 45 C. The biomass was characterized with FTIR and SEM analysis. Desorption studies revealed that the natural biomass could be regenerated using 10mM HNO(3) solution with about 99% recovery and reused in five biosorption-desorption cycles. Therefore, S. albus which is cheap, highly selective and easily regenerable seems to be a promising substrate to entrap lead(II) ions in aqueous solutions.

Assessment of cationic dye biosorption characteristics of untreated and non-conventional biomass: Pyracantha coccinea berries.

This work reports on the assessment of the dye methylene blue biosorption properties of Pyracantha coccinea berries under different experimental conditions. Equilibrium and kinetic studies were carried out to determine the biosorption capacity and rate constants. The highest biosorption yield was observed at about pH 6.0, while the biosorption capacity of the biomass decreased with decreasing initial pH values. Batch equilibrium data obtained at different temperatures (15, 25, 35 and 45 degrees C) were modeled by Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms. Langmuir isotherm model fitted the equilibrium data, at the all studied temperatures, better than the other isotherm models indicating monolayer dye biosorption process. The highest monolayer biosorption capacity was found to be 127.50mg/g dry biomass at 45 degrees C. Kinetic studies indicate that the biosorption process followed the pseudo-second-order model, rather than the pseudo-first-order model. DeltaG degrees , DeltaH degrees and DeltaS degrees parameters of biosorption show that the process is spontaneous and endothermic in nature. The biosorbent-dye interaction mechanisms were investigated using a combination of Fourier transform infrared spectroscopy and scanning electron microscopy. The biosorption procedure was applied to simulated wastewater including several pollutants. The results obtained indicated that the suggested inexpensive and readily available biomaterial has a good potential for the biosorptive removal of basic dye.

Assessment of the biosorption characteristics of a macro-fungus for the decolorization of Acid Red 44 (AR44) dye.

This study focuses on the possible use of macro-fungus Agaricus bisporus to remove Acid Red 44 dye from aqueous solutions. Batch equilibrium studies were carried out as a function of pH, biomass amount, contact time and temperature to determine the decolorization efficiency of biosorbent. The highest dye removal yield was achieved at pH 2.0. Equilibrium occurred within about 30 min. Biosorption data were successfully described by Langmuir isotherm model and the pseudo-second-order kinetic model. The maximum monolayer biosorption capacity of biosorbent material was found as 1.19 x 10(-4) mol g(-1). Thermodynamic parameters indicated that the biosorption of Acid Red 44 onto fungal biomass was spontaneous and endothermic in nature. Fourier transform infrared spectroscopy and scanning electron microscopy were used for the characterization of possible dye-biosorbent interaction and surface structure of biosorbent, respectively. Finally the proposed biosorbent was successfully used for the decolorization of Acid Red 44 in synthetic wastewater conditions.

Biosorption applications of modified fungal biomass for decolorization of Reactive Red 2 contaminated solutions: Batch and dynamic flow mode studies

Biosorption characteristics of a surfactant modified macro fungus were investigated for decolorization of Reactive Red 2 contaminated solutions. Better biosorption efficiency was obtained with a small amount of fungal biomass after modification process. Operating variables like pH, biomass amount, contact time, temperature, dye concentration, flow rate and column size were explored. The biosorption process followed the pseudo-second-order kinetic and Langmuir isotherm models. Thermodynamic data confirm that the biosorption process is spontaneous and endothermic in nature. Under optimized batch conditions, up to 141.53 mg dye g(-1) could be removed from solution in a relatively short time. Modification process was confirmed by FTIR spectroscopy and zeta potential studies. Possible dye-biosorbent interactions were discussed. Good dynamic flow biosorption potential was observed for the suggested biosorbent in simulated wastewater. Overall, batch and continuous mode data suggest that this environmentally friendly and efficient biosorbent may be useful for the removal of reactive dyes from aqueous media.

Utilization of the Phaseolus vulgaris L. Waste biomass for decolorization of the textile dye Acid Red 57: determination of equilibrium, kinetic and thermodynamic parameters.

In the present study, biosorption of Acid Red 57 (AR57) onto a waste biomass of Phaseolus vulgaris L. was investigated by varying pH, contact time, biosorbent concentration and temperature, to determine the equilibrium, thermodynamic and kinetic parameters. The AR57 biosorption was fast, and equilibrium was attained within 20 min. Biosorption equilibrium data fit the Langmuir isotherm model well with high correlation coefficients. According to Langmuir isotherm model the maximum biosorption capacity of Phaseolus vulgaris L. for AR57 dye was determined as 4.09 × 10− 4 mol g− 1 or 215.13 mg g− 1 at 20°C. The thermodynamic parameters (Gibbs free energy, enthalpy and entropy) for the biosorption of AR57 were indicated that the biosorption was spontaneous and exothermic in nature. The pseudo-second-order kinetic model agrees well with the dynamic behavior of the biosorption of AR57 onto P. vulgaris L., under various temperatures. The removal efficiency of the biomass was also examined in real textile wastewater.

Decolorization of a textile dye, reactive red 198 (rr198), by Aspergillus parasiticus fungal biosorbent

The decolorization potential of textile dye Reactive Red 198 (RR198) by Aspergillus parasiticus fungal biosorbent has been investigated as a function of initial pH, contact time, biosorbent and initial dye concentration in a batch system. Maximum dye biosorption capacity 1.03x10-4 mol g-1 was observed at pH 2.0 and 2.0 g L-1 of biosorbent concentration. Biosorption equilibrium was attained within 50 min. The equilibrium data followed Langmuir, Freundlich and Dubinin-Radushkevich isotherm models at 20, 30, 40 and 50oC. Anincrease in the biosorption capacity of A. parasiticus with temperature showed that the decolorization process is endothermic. Results indicated that Aspergillus parasiticus was an effective candidate for textile dye RR198 removal from aqueous solutions.

Nickel exposure and its effects.

The aim of the study was to determine the nickel concentrations of soil and plant specimens taken from a rural area exposed to cement factory emissions and also to determine the blood concentrations and sensitivity conditions observed in humans residing in this rural area. The study was carried out in Çukurhisar, a town in Eskişehir-Turkey, between May 2000 and March 2001. Beside the 108 soil (36 for control) and plant specimens, which were taken from 8 directions from the cement factory, blood samples of the individuals residing in this area were taken from 258 subjects (258 for control) following a physical examination, and patch tests were also applied. The nickel concentrations of the soil and plant specimens taken from different places in different directions of the factory were higher than in the control areas. The physical examination of subjects did not reveal results different from those of the control group except for the diagnosis of contact dermatitis. The analyses of venous blood samples showed that nickel concentrations were found to be within the reference values given for both groups, but higher in the subjects (p<0.001). According to the results of patch tests, sensitivity to nickel was found to be more frequent for the subject group than the control group (p<0.05). According to these results, clinical tools revealed no toxic effects for the subjects, except contact dermatitis. However, sensitivity to patch tests showed that this subject group has been affected compared to the control group and that this effect increased with age.

Biosorption Potential of the Macrofungus Ganoderma carnosum for Removal of Lead(II) Ions from Aqueous Solutions

This paper reports the utilization of a macro-fungus Ganoderma carnosum as a biosorbent material for the removal of lead(II) ions from aqueous solutions. The biosorption potential of G. carnosum was investigated by batch experiments. The influences of physico-chemical parameters like pH, biosorbent dosage, contact time and initial metal ion concentration were evaluated. The biosorption equilibrium was attained in 10 minutes. Equilibrium biosorption data were analyzed by the Freundlich, Langmuir and Dubinin–Radushkevich (D–R) isotherm models. Maximum biosorption capacity of biosorbent was found to be 22.79 mg g− 1 (1.10 × 10− 4 mol g− 1) at the pH value of 5.0. The biosorbent was regenerated using 10 mM HCl solution, with up to 96% recovery, and reused four times in biosorption-desorption cycles successively. Biosorption efficiency of G. carnosum was also examined in a real effluent. The mechanism of the biosorption was investigated with FTIR, SEM and EDAX analysis and the findings suggested that the biosorption process involved in ion exchange as dominant mechanism as well as complexation. The ion exchange mechanism was also confirmed by the mean free energy value obtained from D–R isotherm model.