Evaluation of a Carbonaceous Sorbent Prepared from Pearl Millet Husk for Its Removal of Basic Dyes

Abstract

The capacity of a carbonaceous sorbent prepared from Pearl Millet Husk (PMHC), an agricultural byproduct to remove basic dyes was evaluated by choosing Methylene blue as the test dye. Batch-mode adsorption studies were carried out systematically, involving process parameters, such as agitation time, initial dye concentration, carbon dose, and pH. The adsorption followed a simple first order kinetic equation given by Lagergren and the rate was controlled by both film and intra-particle diffusion processes, isotherm analyses of the equilibrium data involving Freundlich, Langmuir and Redlich-Peterson

models have shown that Freundlich model fits well with the experimental data more precisely, although reasonably better fit was obtained for Langmuir and Redlich-Peterson isotherm models. The adsorption parameters were obtained by

non-linear optimization method and the adsorption capacity derived from Langmuir isotherm model was 82.37 mg/g. The influence of pH on dye removal was insignificant and a portion of the dye was recovered from the spent carbon in organic medium.