The use of Al2O3 - pillared clay in cleaning of aqueous solutions from surfactants

Abstract

The paper describes the Al2O3-pillared clays synthesized by modifying the natural montmorillonite clay with aluminum polyhydroxy complexes and subsequent heat treatment of the modified samples at temperatures of 400 °C and 500 °C. The textural characteristics of natural and Al2O3-pillared clays were determined by the method of low-temperature nitrogen adsorption. The results showed that the obtained materials had a specific surface area, which was 1.7 times larger than the surface of the original clay, and the total pore volume, which was 1.2 more, than the pore volume of the original clay. Anionic surfactants (sodium dodecyl sulfate C12H25OSO3Na and sulfonol C12H25C6H4SO3Na) adsorption results have shown that the clay modifying by polyhydroxocomplexes of aluminum leads to a significant increase in their aniono-exchange capacity. Al2O3-pillared clay exceeds the adsorption capacity of natural clay more than 2 times in the adsorption of sodium dodecylsulfate and sulfonol. It is established that the adsorption isotherms of sodium dodecylsulfate and sulfonol on Al2O3-pillared clays well obey the Freundlich adsorption isotherm equation, which describes multilayer adsorption on a heterogeneous surface of sorbents. Al2O3-pillared clays may be of interest for use in wastewater treatment from anionic surfactants.