Heavy metals are toxic pollutants released into aqueous systems as a result of various activities such as industry, mining and agriculture. There are many methods for the removal of metal ions from solutions including chemical precipitation, complexation, solvent extraction and membrane processes. However, most of these methods are either economically prohibitive or too complicated for the treatment of metals1. Meanwhile, adsorption processes have shown many advantages over these physicochemical methods. They are quite selective, effective and are able to remove various levels of soluble heavy metals in solution. In recent years, considerable attention has been focused on the removal of heavy metals using biosorbents derived from low-cost materials. Several biosorbents such as peat, sawdust, sewage sludge and crop waste have been used for the treatment of metals in aqueous solution. In this study, sawdust, which has environmental benefits in terms of the reuse of solid waste, was tested to evaluate its potential for the treatment of heavy metals. The adsorption rate and capacity per unit mass of sawdust may be important parameters in the treatment process. It determines the sorbent replacement frequency and the economics of operation. In this study, kinetics of metal adsorption on sawdust were studied and described by several models.
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