Application of Biosorption for Removal of Heavy Metals from Wastewater

Abstract

Abstract Fresh water accounts for 3% of water resources on the Earth. Human and industrial activi- ties produce and discharge wastes containing heavy metals into the water resources mak- ing them unavailable and threatening human health and the ecosystem. Conventional methods for the removal of metal ions such as chemical precipitation and membrane iltration are extremely expensive when treating large amounts of water, ineicient at low concentrations of metal (incomplete metal removal) and generate large quantities of sludge and other toxic products that require careful disposal. Biosorption and bioac- cumulation are ecofriendly alternatives. These alternative methods have advantages over conventional methods. Abundant natural materials like microbial biomass, agro-wastes, and industrial byproducts have been suggested as potential biosorbents for heavy metal removal due to the presence of metal-binding functional groups. Biosorption is inlu- enced by various process parameters such as pH, temperature, initial concentration of the metal ions, biosorbent dose, and speed of agitation. Also, the biomass can be modiied by physical and chemical treatment before use. The process can be made economical by regenerating and reusing the biosorbent after removing the heavy metals. Various bioreactors can be used in biosorption for the removal of metal ions from large volumes of water or eluents. The recent developments and the future scope for biosorption as a wastewater treatment option are discussed. Keywords: