Biosorption of a textile dye (Acid Blue 40) by cone biomass of Thuja orientalis: estimation of equilibrium, thermodynamic and kinetic parameters.

Biosorption of Acid Blue 40 (AB40) onto cone biomass of Thuja orientalis was studied with variation in the parameters of pH, contact time, biosorbent and dye concentration and temperature to estimate the equilibrium, thermodynamic and kinetic parameters. The AB40 biosorption was fast and the equilibrium was attained within 50 min. Equilibrium data fitted well to the Langmuir isotherm model in the studied concentration range of AB40 and at various temperatures. Maximum biosorption capacity (q(max)) for AB40 was 2.05 x 10(-4)mol g(-1) or 97.06 mg g(-1) at 20 degrees C. The changes of Gibbs free energy, enthalpy and entropy of biosorption were also evaluated for the biosorption of AB40 onto T. orientalis. The results indicate that the biosorption was spontaneous and exothermic. Kinetics of biosorption of AB40 was analyzed and rate constants were also derived and the results show that the pseudo-second-order kinetic model agrees very well with the experimental data.

Study on the characterization of lead (II) biosorption by fungus Aspergillus parasiticus.

The lead (II) biosorption potential of Aspergillus parasiticus fungal biomass has been investigated in a batch system. The initial pH, biosorbent dosage, contact time, initial metal ion concentrations and temperature were studied to optimize the biosorption conditions. The maximum lead (II) biosorption capacity of the fungal biosorbent was found as 4.02 x 10(-4) mol g(-1) at pH 5.0 and 20 degrees C. The biosorption equilibrium was reached in 70 min. Equilibrium biosorption data were followed by the Langmuir, Freundlich and Dubinin- Radushkevich (D-R) isotherm models. In regeneration experiments, no significant loss of sorption performance was observed during four biosorption-desorption cycles. The interactions between lead (II) ions and biosorbent were also examined by FTIR and EDAX analysis. The results revealed that biosorption process could be described by ion exchange as dominant mechanism as well as complexation for this biosorbent. The ion exchange mechanism was confirmed by E value obtained from D-R isotherm model as well.

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 x 10(- 4) mol g(- 1) or 215.13 mg g(- 1) at 20 degrees 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.

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 x 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.

Kinetics and equilibrium studies for the adsorption of Acid Red 57 from aqueous solutions onto calcined-alunite.

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, K(L), 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.

Biosorption characteristics of Bacillus sp. ATS-2 immobilized in silica gel for removal of Pb(II).

The bacterial strain Bacillus sp. ATS-2 isolated from Pb(II) polluted soil was immobilized with a silica matrix and Pb(II) biosorption properties of immobilized biosorbent were examined. Optimum biosorption conditions were investigated in the fixed bed column with the variation in the parameters of pH, bed length, flow rate and influent concentration. The Pb(II) biosorption equilibrium was attained within 60 min and the maximum biosorption yield for silica gel immobilized Bacillus sp. ATS-2 was determined as 91.73% at pH 4.0. The higher biosorption yields were observed at flow rates of 60 and 180 ml h(-1). The optimum bed length for the column was found as 10 cm. Data obtained from batch studies were evaluated by Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. The maximum monolayer capacity of Bacillus sp. ATS-2 for Pb(II) was 2.36 x 10(-5) mol g(-1). The involvement of the functional groups on the surface of immobilized cells in biosorption process was also evaluated by FTIR spectral analysis.

Biosorption characteristics of Aspergillus flavus biomass for removal of Pb(II) and Cu(II) ions from an aqueous solution.

The Pb(II) and Cu(II) biosorption characteristics of Aspergillus flavus fungal biomass were examined as a function of initial pH, contact time and initial metal ion concentration. Heat inactivated (killed) biomass was used in the determination of optimum conditions before investigating the performance of pretreated biosorbent. The maximum biosorption values were found to be 13.46 +/- 0.99 mg/g for Pb(II) and 10.82 +/- 1.46 mg/g for Cu(II) at pH 5.0 +/- 0.1 with an equilibrium time of 2 h. Detergent, sodium hydroxide and dimethyl sulfoxide pretreatments enhanced the biosorption capacity of biomass in comparison with the heat inactivated biomass. The biosorption data obtained under the optimum conditions were well described by the Freundlich isotherm model. Competitive biosorption of Pb(II) and Cu(II) ions was also investigated to determine the selectivity of the biomass. The results indicated that A. flavus is a suitable biosorbent for the removal of Pb(II) and Cu(II) ions from aqueous solution.

Zn(II) biosorption properties of Botrytis cinerea biomass.

The study was aimed of determining the Zn(II) sorption performance of Botrytis cinerea (B. cinerea) biomass as a new biosorbent. Heat inactivated biomass was used in the determination of optimum conditions. The rate and extent of accumulation were effected by pH, contact time and initial zinc ion concentrations. The uptake capacity of B. cinerea was increased by chemical and physical pretreatment of the cells when compared with the native biomass. The maximum removal of Zn(II) at pH 5.0-6.0 was found to be 12.98+/-0.9623 mg g-1 at initial Zn(II) ion concentration of 100 mg l-1 by heat inactivated biomass. Freundlich and Langmuir isotherm models were used to evaluate the data and regression constants were derived. The biosorbent was regenerated using 10 mM HCl solution, with up to 98% recovery and reused five times in biosorption-desorption cycles successively. Competitive biosorption experiments were performed with zinc in the presence of copper, cadmium and nickel ions simultaneously. The nature of the possible cell-metal ions interactions was also evaluated by chemical and instrumental analysis including infrared spectroscopy, scanning electron microscopy and X-ray energy dispersion analysis.

Determination of the equilibrium, kinetic and thermodynamic parameters of adsorption of copper(II) ions onto seeds of Capsicum annuum.

Adsorption of copper ions onto Capsicum annuum (red pepper) seeds was investigated with the variation in the parameters of pH, contact time, adsorbent and copper(II) concentrations and temperature. The nature of the possible adsorbent and metal ion interactions was examined by the FTIR technique. The copper(II) adsorption equilibrium was attained within 60 min. Adsorption of copper(II) ions onto C. annuum seeds followed by the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Maximum adsorption capacity (q(max)) of copper(II) ions onto red pepper seeds was 4.47x10(-4) molg(-1) at 50 degrees C. Three kinetic models including the pseudo-first-order, pseudo-second-order and intraparticle diffusion equations were selected to follow the adsorption process. Kinetic parameters such as rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was indicated that the adsorption of copper(II) ions onto C. annuum seeds could be described by the pseudo-second-order kinetic model and also followed the intraparticle diffusion model up to 60 min, but diffusion is not only the rate controlling step. Thermodynamics parameters such as the change of free energy, enthalpy and entropy were also evaluated for the adsorption of copper(II) ions onto C. annuum seeds.