Enhancement of Lewis acidity in layer aluminosilicates. Treatment with acetic acid

Abstract

The effect of exposure of Wyoming bentonite to glacial acetic acid has been studied by F.t.i.r., X.p.s, SEM and acidity measurements, in order to investigate the possibility of using such a non-aqueous technique as an alternative activation process. Treatment with glacial acetic acid, results in an overall increase in the concentration of acid sites. However, the number of Brønsted sites is reduced, whereas the population of Lewis sites increases. This change is accompanied by the leaching out of Al³⁺, but with no extensive loss of crystallinity. Treatment with mineral acids results in an increase in Brønsted acidity.