Biosorption of heavy metals–An overview

During the last two decades, extensive attention has been paid on the management of environmental pollution causal by hazardous materials such as heavy metals. Decontamination of heavy metals in the soil and water around industrial plants has been a challenge for a long time. A number of methods have been developed for the removal of heavy metals from liquid wastes such as precipitation, evaporation, electroplating, ion exchange, membrane processes, etc. However, these methods have several disadvantages such as unpredictable metal ion removal, high reagent requirement, generation of toxic sludge, etc. Biosorption is a process, which represents a biotechnological innovation as well as a cost effective excellent tool for removing heavy metals from aqueous solutions. This article provides a selective overview of past achievements and present scenario of biosorption studies carried out on some promising natural biosorbents (algae, fungi, bacteria, yeast) and some waste materials which could serve as an economical means of treating effluents charged with toxic metallic ions.