CHAPTER 3: Role of Plant Biomass in Heavy Metal Treatment of Contaminated Water

This chapter gives an account of recent developments in biomass derived from plants as treatment agents in removal of heavy metals from wastewater. Several conventional methods, like chemical precipitation, lime coagulation, ion exchange, reverse osmosis and solvent extraction, are being used for metal removal. These conventional methods for heavy metal removal from wastewaters are often cost prohibitive, having inadequate efficiencies at low metal concentrations. The major advantages of biosorption over conventional treatment methods include low cost and high efficiency of metal removal from dilute solutions, minimization of chemical and/or biological sludge, no additional nutrient requirement, and regeneration of the biosorbent and the possibility of metal recovery. This chapter also describes the types of mechanism involved in the biosorption process and the variables affecting the biosorption of different metals. Recent developments in plant-based biosorbents, their types and the metals removed are tabulated.