Derivation of empirical model for computing the sorption capacity of Pb(II), Cr(III) and Mn(II) ion adsorption onto zinc chloride activated sawdust

Abstract

The work investigated the performance of zinc chloride activated sawdust as potential adsorbent for the removal of Pb(II), Cr(III) and Mn(II) ions from aqueous solution. The raw sawdust was collected, processed and characterized using scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) to assess its potential for the removal of lead, chromium and manganese from effluent wastewater. Thereafter, batch adsorption technique was employed to evaluate the effects of adsorption variables such as pH, initial metal ion concentration and adsorbent dosage including contact time on the sorption efficiency of the sawdust. Experimental data obtained were then analyzed using selected reaction controlled kinetic model such as Pseudo-First order, Pseudo-Second order and the simple elovich kinetic model. The kinetic model that best described the adsorption data was thereafter selected by employing non-linear regression techniques using selected error function models. Based on the kinetic models that best explained the adsorption data, empirical models were derived using the procedures and assumptions of HO and McKay 2000. SEM and FT-IR results revealed the presence of micropores and polar functional group within the structure of the sawdust thus making it a good candidate for metal ion removal. More also, the empirical model derived have been adequately executed and can form the bedrock for further research in related areas.