Remediation of heavy metals (Cr, Zn) using physical, chemical and biological methods: a novel approach

Abstract

Heavy metal pollution has become one of the most significant environmental problems globally leading to ecological imbalance. There are many physicochemical and biological methods for the removal of heavy metals. Most of the physicochemical methods are less eco-friendly and less cost-effective, while the biological methods are slow in nature. Recently, nanoparticles have been suggested as efficient alternatives to existing treatment methods, in both resource conservation and environmental remediation of anthropogenic compounds. Nanotechnologies are pervasive solution vectors in our economic environment. Biological synthesis of nanoparticles has grown markedly to create novel materials that are eco-friendly, cost-effective and stable with great importance in wider application in the areas of electronics, medicine and agriculture. Thus, the current work focuses on a comparative remediation of heavy metals using physical, chemical and biological methods and nano-structured copper iodide is used as an adsorbent for the removal of chromium (Cr) and zinc (Zn). In the present study, we have experimented with a few methods in physical (UV light irradiation, adsorption studies using CuI), chemical (UV photocatalysis using CuI) and biological methods (using co-culture bacteria strains). A combination of chemical and biological methods was also probed using CuI–polyvinyl alcohol nano-composite containing bacterial co-cultures. The synthesized nano-composite was characterized using scanning electron microscope. The present study revealed that the most effective and cost-friendly method was using biologically prepared nano-composite of CuI (a combination of both chemical and biological methods) to remediate heavy metals Cr and Zn with a removal efficiency up to ~ 67% for Cr and ~ 55% for Zn at the end of 48 h.