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 index etc. and, has been widely used in many scientific applications like organoclay. Meanwhile, adsorption themed studies with montmorillonite which depend on ion exchange processes by means of a variety of organic compounds like ammonium and phosphonium salts which are becoming very popular because of their usages in organoclay and polymer nanocomposites due to their higher thermal strengths. In this purpose, different types of phosphonium salts, namely Hexadecyl Triphenyl Phosphonium Bromide (HTPB), Hexadecyl Tributyl Phosphonium Bromide (HTBPB), and Tetraphenyl Phosphonium Bromide (TPB), were used to investigate the effect of these surfactants on the adsorption behavior of Na-montmorillonite. The last one was composed only of one aromatic head without an organic chain (TPB), whereas the others are in an organic chain with three branches (HTBPB) and an organic chain including one aromatic head (HTPB). The adsorption properties of these surfactants on the sample were also supported with the surface characterization tests, the zeta potential, surface tension, and flocculation measurement. The results clearly indicated that the adsorption behavior of these surfactants depend on their structure.