Removal of Ag(I) and Zn(II) ions from single and binary solution using sulfonated form of gum arabic-powdered mushroom composite hollow semispheres: Equilibrium, kinetic, thermodynamic and ex-situ studies

摘要

In the present study, the biosorption potential of sulfonated plant gum-mushroom biocomposite (SfGM) for the removal of Ag(I) and Zn(II) was investigated in a single and binary system. Various parameters viz., pH, initial metal concentration, biomass dosage, contact time, temperature and gum dosage were optimized. The metal adsorption was found to reach equilibrium at 60 min. In single metal system, maximum adsorption capacity of SfGM was calculated to be 137.8 mg/g for Ag(I) and 287.9 mg/g for Zn(II) ions. In a binary system, an antagonistic nature was observed and Ag(I) uptake was found to be higher as compared to Zn(II) uptake owing to the difference in their ionic radii. Equilibrium studies suggested a heterogenous mode of adsorption. Kinetic studies suggested a chemical mode of adsorption in a binary system and a physical mode in a single system. Thermodynamic studies suggested an endothermic nature of biosorption in case of Zn(II) whereas an exothermic nature was found to be predominant in case of Ag(I) biosorption. Interaction effects were studied using extended Langmuir and SRS equations. Spectroscopic analysis viz., SEM, EDX and FT-IR studies validated the above mentioned results. Ex-situ applications were performed using electroplating wastewater in a packed bed column at varying bed heights, flow rates and dilutions. The column data was analyzed using bed depth service time (BDST) model and Thomas model. The present study highlights the potential of sulfonated form of gum-mushroom composite as cost effective adsorbent for the removal of heavy metals from aqueous environment. (C) 2014 Elsevier B.V. All rights reserved.