Reduction of Cr (VI) in Electroplating Wastewater and Investigation on the Sorptive Removal by WBAP

摘要

The aim of the present investigation was to study the removal of total chromium from the electroplating industry effluent using Weathered Basalt Andesite Products (WBAP). The reduction of Cr (VI) to Cr (III) by hydrazinium sulfate (HS) was adopted. The sor-bent WBAP before and after sorption, was characterized by FTIR, X-ray diffraction, SEM, TEM, and TGA methods. The effects of various parameters such as hydronium ion concentration, shaking time, sorbent dose, initial metal ion concentration, and temperature on the removal of Cr (III) from aqueous solution was studied. Thermodynamic parameters (Alf, A5°, and AG°) for the sorption process were evaluated. Freundlich, Langmuir, and Dubinin-Kaganer-Radushkevich isotherm models were examined to describe the sorption isotherms. Analysis of sorption results obtained showed that the sorption pattern followed the Freundlich sorption isotherm. Langmuir maximum sorption capacity of WBAP for Cr (III) was found to be 12.07 mg/g. The process follows Pseudo second order rate and surface diffusion is identified as the predominating mechanism. The effluent having average discharge of total chromium 90 mg/L was successfully treated with the same sorbent with a removal of 85.65%.