Adsorption of Heavy Metal Ions from Aqueous Solutions onto Rice Husk Ash Low Cost Adsorbent

In the present study, adsorption of Zn (II), Cd (II) and Hg (II) ions on rice husk ash (RHA) has been investigated in single, binary and tertiary systems. Batch experiments were also carried out for mono- and multi-component systems with varying metal ions concentrations (mg/l) to investigate the competitive adsorption characteristics. Rice husk ash (RHA) has been studied for their adsorption properties pertaining to mono component solutions of metal ions. However, to treat waste water with new materials, their performance needs to be ascertained in multi component system. The scanning electron micrographs (SEM) of rice husk ash surfaces before and after the adsorbent was equilibrated with the metal ions solution, clearly establishes the presence of the metal ions and some surface modifications can be observed on the rice husk ash particles adsorption with (i) surface chemistry of the pellets on the surface of rice husk ash and (ii) inside layers of the rice husk ash. Applicability of the isotherm models namely Freundlish and Langmuir to predict the equilibrium uptake of Zn(II), Cd(II) and Hg(II) in mono, binary and tertiary systems have also been tested.