Adsorption kinetics and isotherm models of heavy metals by various adsorbents: An overview

Heavy metal pollution has become one of the most severe environmental issues. Adsorption is an effective method for removing heavy metals from aquatic environments. The adsorption isotherm and kinetics models can provide information on the adsorption process, maximal adsorption capacity, and mass transfer steps, which are essential to evaluate the performance of an adsorbent and to design an adsorption system. In this review, the adsorption kinetics and isotherms of heavy metals by various adsorbents were summarized and discussed in depth. First, the sources of heavy metal pollution and the adsorption technology to remove heavy metals were reviewed. The adsorption capacity of Cu, Cd, Zn, Ni, Cr, As, Fe, Hg,…