Comparative evaluation for the adsorption of toxic heavy metals on to millet, corn and rice husks as adsorbents

Abstract

This study was carried out to evaluate the efficiency of metals (Ni, Cr, and Mn) removal using, raw and carbonized rice, millet and corn husks as low cost adsorbents. The sorption of these metal ions from aqueous solution was determined using Atomic Absorption Spectroscopy Analysis (AAS). Characterisation of the adsorbents using Fourier Transform Infra Red) FTIR) and Scan Electron Microscopy (SEM) images revealed some changes before and after the adsorption process. This indicated that, most likely adsorption has been taken place between the metal ions and the adsorbents in the aqueous solution. Batch experiments were carried out to determine the effect of different parameters such as adsorbent dose, pH of the medium, contact time and agitation rate. The result obtained showed that the sorption process was largely dependent on metal ion concentration, adsorbent dose and contact time. The experimental data was analyzed using paired sample – T test. The study also showed that, all the husks were effective for the quantitative removal of various toxic heavy metals and can be used as low cost and highly efficient adsorbents for the removal of heavy metal ions from industrial effluents.