ABSTRACT
This chapter discusses sorption/adsorption focuses on the solid—liquid system. The pH effect on heavy metal adsorption in the presence of organic matters may be different from that in the absence of organic matter. Different metal ions behave differently in the adsorption process. In addition, the radius of hydrated ion is much larger than that of the free ion, which may affect the adsorption. It should be noted that the effect of pH is much more important than ionic strength. In addition, ionic strength may greatly reduce the metal sorption onto biosorbents. Heavy metal ion adsorption capacities of various activated carbons at a fixed pH and under a constant temperature can be described by traditional adsorption isotherms. Heavy metal adsorption onto activated carbons is due to a series of adsorption reactions between the metal ions and the organic functional groups in the activated carbons. Metal oxides can remove heavy metal ions through adsorption.
