Synergistic Effect of Pistachio Shell Powder and Nano-Zerovalent Copper for Chromium Remediation from Aqueous Solution

Abstract

Pistachio shell powder supported nano-zerovalent copper (ZVC@PS) material prepared by borohydride reduction, was characterized using SEM, FTIR, XRD, TGA/DTA, BET, and XPS. SEM, XRD, and XPS revealed the nano-zerovalent copper to consist of a core-shell structure with CuO shell and Cu(0) core with a particle size of 40–100 nm and spherical morphology aggregated on PS biomass. ZVC@PS was found out to contain 39% (w/w %) Cu onto the pistachio shell biomass. Batch sorption of Cr(VI) from the aqueous using ZVC@PS were studied, and was optimized for dose (0.1–0.5 g/L), initial Cr(VI) concentration(1–20 mg/L) and pH (2–12). Optimized conditions were 0.1 g/L doses of sorbent and pH = 3 for Cr(VI) adsorption. Langmuir and Freundlich adsorption isotherm models fitted well to the adsorption behavior of ZVC@PS for Cr(VI) with a pseudo-second-order kinetic behavior. ZVC@PS (0.1g/L) exhibits qmax for Cr(VI) removal up to 111.1 mg/g. XPS and other spectroscopic evidence suggest the adsorption of Cr(VI) by pistachio shell powder, coupled with reductive conversion of Cr(VI) to Cr(III) by ZVC particles to produce a synergistic effect for the efficient remediation of Cr(VI) from aqueous medium.