Bioadsorption of heavy metals

Abstract

Pollution caused by heavy metals is one of the most serious environmental problems for society. Industrial activities increase the concentration of heavy metals such as Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) in aquatic systems and mainly in the fields of mechanics, electrics, electronics, tanning, galvanization, oil industries and mining. Biomagnification of these metals occurs through the toxicity of the trophic for humans. As a remedial measure, it is for scientists to find new biosorbents which are able to ameliorate the possible toxic effects of heavy metals in water bodies. Studies of bioadsorption have identified this as a real alternative to wastewater treatment, especially for the removal of heavy metals. This chapter explores (1) the characterization of new biosorbents via surface acid-base titration, where the type of functional groups can be tentatively computed, (2) kinetics of bioadsorption (pseudo-first and second order), (3) bioadsorption as a function of pH and (4) bioadsorption as a function of metal concentration in solution (Langmuir, Freundlich, Sips, Redlich-Peterson, Tóth, Frumkin and Temkin isotherms), where the maximum adsorption capacity can be determined under different experimental conditions. The majority of bioadsorption studies have been carried out at laboratory scale; however, future studies will be conducted at industrial scale as a way to remediate heavy metal pollution in water bodies. Different commercial biosorbents and their characteristics are presented in this chapter.