Green Synthesis of Nickel Nanoparticles Using Pomegranate Peel for Cr(VI) Removal from Wastewater: A Sustainable and Low-cost Approach

Abstract

This study successfully synthesized nickel nanoparticles (Ni@NPs) utilizing an aqueous extract of pomegranate (Punica granatum L.) peel waste as an environmentally friendly, cost-effective bioreductant and stabilizing agent. The produced nanoparticles were evaluated using UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM-EDX). The crystallization of Ni@NPs with nanoscale dimensions was validated using X-ray diffraction and scanning electron microscopy investigations. The efficacy of green-synthesized Ni@NPs in eliminating hexavalent chromium Cr(VI) from wastewater was assessed by time-dependent batch tests. Under optimal conditions, the nanoparticles attained a maximum Cr(VI) removal effectiveness of 95.2% in 150 min. Kinetic analysis demonstrated that the removal process adhered more closely to a pseudo-first-order model R² = 0.9783, k₁ = 0.0198 min^–1), suggesting a mechanism dominated by chemisorption. This study illustrates a dual sustainability benefit: the valorization of agro-waste from fruit processing and the synthesis of an efficient, environmentally benign nanomaterial for heavy metal remediation, thereby advancing green chemistry and circular economy principles.