Lagenaria siceraria peel biomass as a potential biosorbent for the removal of toxic metals from industrial wastewaters

Abstract

The discharge of toxic metals from industries is a major environmental problem. It is, therefore, crucial to find efficient methods for their removal. The present study analysed the Lagenaria siceraria (LS) peel biomass for the elimination of chromium, cobalt, copper, iron, mercury, silver and zinc from wastewaters. Formaldehyde treated and untreated biomass was also tested. The ability of the biomass to adsorb metal ions was found to depend on pH, the original concentration of ions, and the biomass treatment. With untreated biomass, the order of adsorption was copper > zinc > cobalt > iron > silver > chromium > mercury, with treated biomass, the order was copper > mercury > iron > chromium > cobalt > silver > zinc, and at pH 4–5, the order was copper > iron > cobalt > chromium > silver > zinc > mercury. The biomass had remarkable affinity for copper under all the conditions. Since LS is a vegetable cultivated on a large scale, adsorption strategies based on its biomass are expected to be convenient, eco-friendly and cost effective.