Biosorption of Mercury onto Protonated Pistachio Hull Wastes – Effect of Variables and Kinetic Experiments

Abstract

Abstract-Batch parametric experiments were performed to study the applicability of protonated pistachio hull waste as a sorbent with respect to the effect of pH of the solution, initial metal concentration, sorbent dosage and temperature on the metal removal efficiency. Optimum conditions for mercury removal were found to be pH 7.0 and adsorbent dose -1.0 g/L .The metal uptake increased with increase in the initial concentration of the metal. The sorption process was identified as endothermic in nature favouring use of high temperature. The kinetic studies revealed that pseudo-second order model fitted well and the constants were determined. The pseudo-second order rate constant and maximum uptake capacity were found as 1.99 × 10 -3 g mg -1 min -1 and 48.78 mg g -1 with 50 mg L -1 metal concentration. Thermodynamic studies were conducted and the activation energy for the adsorption of mercury onto was found to be 10.26 KJ/ mol. Index Terms-Absorbent, metal removal, pistachio hull waste.

Biosorption of mercury(II) from aqueous solution by fungal biomass Pleurotus eryngii: Isotherm, kinetic, and thermodynamic studies

“…After that the contents of the flask were filtered through 0.45 mm syringe filter and analyzed by HG-AAS (Hydride-Generation Atomic Absorption Spectrophotometer). For optimization pH (3)(4)(5)(6)(7)(8)(9), biomass dosages (0.15-0.35 g), Hg(II) ion concentrations (0.5-10 mg L 21 ), contact time (1-6 min), and temperature (30-608C) were studied. Five replicates of each sample were analyzed and the mean value is reported.…”

“…To decrease the high concentration of Hg(II) ion up to the permissible level from aqueous solution, various physico ‐ chemical processes; such as chemical precipitation, electrode deposition, reverse osmosis and evaporation electrolysis, ion exchange, adsorption, cementation, membrane filtration, and liquid ‐ liquid extraction have been utilized . Large capital investment, running costs and disposal of toxic sludge are the major shortcoming of these processes .…”