Removal of heavy metals by biosorption

Industrialization and urbanization have resulted in increased releases of toxic heavy metals into the natural environment comprising soils, lakes, rivers, groundwaters and oceans. Research on biosorption of heavy metals has led to the identification of a number of microbial biomass types that are extremely effective in bioconcentrating metals. Biosorption is the binding and concentration of adsorbate from aqueous solutions by certain types of inactive and dead microbial biomass. The novel types of biosorbents presently reviewed are grouped under fungal biomass, biomass of non-living, dried brown marine algae, agricultural wastes and residues, composite chitosan biosorbent prepared by coating chitosan, cellulose-based sorbents and bacterial strains. The reports discussed in this review collectively suggest the promise of biosorption as a novel and green bioremediation technique for heavy metal pollutants from contaminated natural waters and wastewaters.