Algal biosorption of heavy metals

Abstract

Metal-bearing effluent can be removed by conventional treatment such as chemical precipitation, electrochemical cells, reverse osmosis, and ion exchange; however, each treatment method has limitations. Sorption, particularly biosorption, has become one of the alternative treatments to conventional treatments of wastewaters and industrial effluents. The treatment of industrial wastewater from aqueous solutions employing biosorption technology is an advanced and novel technology. Basically, sorption is the process of assimilation of particles from one phase to another phase. The particles move from the bulk liquid and get amalgamated in the solid surface. The particles bound to the solid surface by physical (Van der Waal's forces) or chemical interaction (chemical bonds). Biosorption has been chosen as an alternative remedial solution because of its high metal-uptake capacity, greater surface area with reactive sorbents, and, above all, low cost. Many biomaterials available in nature have been employed as biosorbents for the desired pollutant removal. Algae are of special interest for the development of new biosorbent material due to their high sorption capacity and ready availability in practically unlimited quantity. Particularly, macroalgae are found to have greater metal uptake capacity. Seaweed (macroalgae) collected from the ocean has shown impressive biosorption of metals. Brown algae, especially, contain high amounts of alginate, which are well protected within brown algae's cellular structures, and copious carboxylic groups capable of capturing cations present in solutions. This chapter discusses the significance of the algal resource in the removal of metals from waste streams and provides a brief overview of marine brown algae, its properties, and their potential applications for biosorption.