Effect of Nitric Acid Concentration on the Properties of Bentonite Clay

Bentonite is a clay mineral commonly used in various applications, particularly in wastewater treatment, due to its excellent natural adsorption properties.The objective of the present study was to investigate the effect of nitric acid activation on the composition and surface properties of bentonite clay.The bentonite was modified with different concentrations of nitric acid (1 M, 5 M, and 10 M), and the samples were characterised using X-ray fluorescence spectrometry (XRF), Brunauer-Emmett-Teller (BET), cation exchange capacity (CEC) and thermogravimetric and differential scanning calorimetry (TG-DSC) analysis.The XRF results showed that acid activation increased the amount of silicon oxide (SiO2) while decreasing the amount of other oxides like alumina (Al2O3), iron oxide (Fe2O3), and magnesium oxide (MgO).The specific surface area, pore volume, and CEC value of the bentonite clay increased significantly as the acid concentration increased from 1 M to 10 M. The total weight loss for the samples raw bentonite (RB), activated bentonite 1 M (AB1), activated bentonite 5 M (AB5), and activated bentonite 10 M (AB10) was 79.47, 75.42, 75.20, and 74.78%, respectively.