Sibel Tunali

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.

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.

Adsorption Potential of Lead(II) Ions from Aqueous Solutions onto Capsicum annuum Seeds

Abstract The purpose of this work was to evaluate the adsorption potential of Capsicum annuum seeds, in a batch system for the removal of lead(II) ions from aqueous solutions. The experimental results showed that this agricultural by‐product was effective in removing lead(II) ions. The FT‐IR analysis indicated that the mechanism involved in adsorption of lead(II) ions by seeds of C. annuum was mainly attributed to lead(II) binding of amino and hydroxyl groups. Adsorption equilibrium approached within 40 min. The adsorption data fitted well to the Langmuir isotherm model. The maximum adsorption capacity (q max) was 1.87×10−4 mol g−1. Pseudo‐second‐order kinetic model was applicable to all the adsorption data over the entire time range. The thermodynamic parameters indicated that the adsorption process is spontaneous since Gibbs free energy values are negative, which are between −26.92 and −30.77 kJ mol−1 at the temperature range of 20–50°C.