Recovery of precious metals through biosorption - A review

Recovery of precious metals like gold, silver, palladium platinum etc. is interesting due to its high market prices along with various industrial applications. Conventional technologies viz, ion exchange, chemical binding, surface precipitation etc. which been have been developed for the recovery of such metals are not economically attractive. Biosorption represents a biotechnological innovation as well as a cost effective excellent tool for recovery of precious metals from aqueous solutions. A variety of biomaterials are known to bind the precious metals including algae, fungi, bacteria actinomycetes, yeast etc. along with some biopolymers and biowaste materials. The metal binding mechanism, as well as the parameters influencing the uptake of precious metals and isotherm modeling are presented. This article provides an overview of past achievements and present scenario of biosorption studies carried out on the use of some promising biosorbents which could serve as an economical means for recovering precious metals. The present review also highlights the use of biosorbents in real situations and hopes to provide insights into this research frontier. (C) 2010 Elsevier B.V. All rights reserved.