Abstract

Water pollution is one of the most serious problems due to the rapid industrial development that discharges inorganic and organic waste to the aquatic environment in water soluble and insoluble forms. Some of the water soluble wastes contain toxic metals ions which have harmfull effect to all forms of life and these enter the food chain through the disposal of waste in water channels. Toxic metals such as Pb2+, Hg+, Cd2+,Cr2+ etc are non-biogradable, accumulate and their concentrations are increased along the food chain. A number of conventional methods viz; chemical precipitation, evaporation, electroplating, ion exchange, membrane processes etc have been employed for the removal of toxic metals ions from liquid water. However all these processes are expensive and have shortcomings such as incomplete removal of toxic metals, limited tolerance to pH change, moderate or no metal selectivity, production of toxic sludge or other products that also need disposal. The use of sorbents of biological origin may be considered ideal for the purpose of biosorption of toxic metals because of their potentials for toxic metal uptake from wastewater have already been proved. The main advantage of biosorption is that it is a cheap process, with good toxic metal recovery results and ecofriendly. In this article, the biosorption process, biosorbents, preparation and characterization of biosorbent, spectroscopic analysis and biosorption kinetic models have been discussed as an important aspect of toxic metals management strategies.