Biosorption: An eco-friendly alternative for heavy metal removal

Abstract

Heavy metals occur in immobilized form in sediments and as ores in nature. However due to various human activities like ore mining and industrial processes the natural biogeochemical cycles are disrupted causing increased deposition of heavy metals in terrestrial and aquatic environment. Release of these pollutants without proper treatment poses a significant threat to both environment and public health, as they are non biodegradable and persistent. Through a process of biomagnification, they further accumulate in food chains. Thus their treatment becomes inevitable and in this endeavor, biosorption seems to be a promising alternative for treating metal contaminated waters. This technology employs various types of biomass as source to trap heavy metals in contaminated waters. The biosorbent is prepared by subjecting biomass to various processes like pretreatment, granulation and immobilization, finally resulting in metal entrapped in bead like structures. These beads are stripped of metal ions by desorption which can be recycled and reused for subsequent cycles. This technology out- performs its predecessors not only due to its cost effectiveness but also in being eco-friendly i.e., where other alternatives fail. Key words: Biosorption, biomass, biosorbents, pretreatment, immobilization.