INVESTIGATION OF ADSORPTION BEHAVIOR OF PHOSPHONIUM SALTS ONTO Na-MONTMORILLONITE

Abstract

Montmorillonite is an important clay mineral due to its cation exchange capacity and technological properties such as swelling and gelling. It has been widely used in many scientific applications like organoclay. Adsorption studies, involving montmorillonite in the presence of variety of organic compounds, like ammonium and phosphonium salts, are very important because of their application in organoclay and polymer nanocomposites. These materials have a high thermal resistivity. Different types of phosphonium salts, including hexadecyl triphenyl phosphonium bromide (HTPB), hexadecyl tributyl phosphonium bromide (HTBPB), and tetraphenyl phosphonium bromide (TPB), were used to investigate their adsorption on Na-montmorillonite. They have different structures and TPB contains only one aromatic part without any organic chain, HTBPB possess an organic chain with three branches while HTPB has an organic chain and an aromatic part. The adsorption of the surfactants was supplemented with other properties such as zeta potential, surface tension, and ability to flocculation. The results indicated that the adsorption behavior of these surfactants depended on their structure.