Modification of Ntezi bentonite structure by hydrochloric acid: Process kinetics and structural properties of the modified samples

Abstract

Bentonite from Ntezi was modified by reacting it with different concentrations of hydrochloric acid solutions. The modified samples were analysed by x-ray fluorescence. The kinetics of the modification reaction was studied by performing the experiment at different temperatures and times. Results of the analysis of the modified samples showed that the octahedral cations were removed which altered the chemical composition of the bentonite. The surface area and adsorptive capacity of the bentonite were improved after the modification. The kinetic studies showed that the acid modification reaction is controlled by the product layer diffusion and can be represented by [1-(I-X)1/3]2 = k t; where, X is the fraction of the bentonite dissolved at time t. The activation energy was determined to be 24.98 kJ/mol.