Biosorption of Mercury(Ⅱ) from Aqueous Solution by Fungal Biomass Pleurotus eryngii: Isotherm, Kinetic, and Thermodynamic Studies

摘要

In present study, biosorption of mercury(Ⅱ) ions from aqueous solution on Pleurotus eryngii fungal biomass was investigated. Different experimental parameters such as the effects of pH, sorbent dose, initial Hg(Ⅱ) ion concentration, contact time, and temperature were evaluated systematically. The sorption process was relatively fast and ＞ 98% removal of Hg(Ⅱ) was achieved within 5 min at pH 7.0. To analyze the suitability of the process and maximum amount of metal uptake, Langmuir and Freundlich isotherm models were applied. The biosorption capacity of P. eryngii fungal biomass was found to be 34.01 mg g~(-1). Among kinetic models studied, the pseudo-second order was the best applicable model to describe the sorption process. Thermodynamic parameters of Hg(Ⅱ) sorption were evaluated by applying the Van't Hoff equation which indicates that the sorption process was exothermic and spontaneous by increased randomness at the solid-solution interface. The adsorbed Hg(Ⅱ) ions were easily desorbed from the fungal biomass using 5 M HCl solution with higher effectiveness and can be reused up to five cycles. The possible nature of cell-metal ion interactions were evaluated by FTIR, SEM, EDX and pH_(pzc) analysis. These examinations indicates the involvement of different electronegative functionalities in the binding of Hg(Ⅱ) metal ions on the surface.