Biosorption: A Novel Biotechnological Application for Removal of Hazardous Pollutants

Absorption is an emerging biotechnological innovation that involves removing/remediation of organic and inorganic substances like heavy metals, pigments, dyes, phenolics and pesticides from aqueous solution by economical alternate biological materials. A number of biomasses of different genera have been recognized to possess good biosorption capacity. It includes living or dead microorganisms like algae, bacteria, fungi and yeast and their components such as exopolysaccharides, seaweeds and plant materials and industrial and agricultural waste; natural residues are employed as sorbent in biosorption process. Biosorption process involves a solid phase and liquid phase (solvent) containing a dissolve species to be sorbed (sorbate/metal ions). It is a physicochemical, passive, rapid, reversible and metabolic-independent process. The binding characteristics of biological materials are attributed to the functional groups present on their surface. Mechanisms involved in the biosorption process include complexation, adsorption-complexation on surface and pores, ion exchange, membrane filtration, microprecipitation, heavy metal hydroxide condensation onto the biosurface and surface adsorption. Time, temperature, pH, concentration of organic pollutants and biomass in solution have a significant role in this process. It is an excellent way to treat industrial waste effluents, precious metal recovery, offering significant advantages like the low-cost, availability, profitability, ease of operation, efficiency and effectiveness and eco-friendly biological method. The aim of this article is to bring out the role of biosorption in the treatment and management of toxic waste.