Modification of bentonite by combination of reactions of acid-activation, silylation and ionic exchange

Abstract

The aim of this study is to analyze different strategies of modification of bentonite (Bent) combining reactions of cationic exchange, silylation and acid activation. Six samples of modified bentonite were prepared: silylated bentonite (S-Bent), acid-activated bentonite (A-Bent), exchanged clay (E-Bent), silylated and acid-activated clay (S-A-Bent), exchanged and acid-activated clay (E-A-Bent), and exchanged, silylated and acid-activated bentonite (E-S-A-Bent). To study the effectiveness of the different treatments, X-rays diffraction analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy and water absorption tests were performed. After silylation reaction, the modified clay presented an increase in the basal spacing as well as a significant reduction in the equilibrium water uptake percentage. The results were markedly improved when the silylated and acid-activated bentonite was further modified by cationic exchange reaction.