Effects of Hydrochloric and Acetic Acid Modification on the HTAB and K+ Adsorption Characteristics of Natural Zeolites

Abstract

In this study, the effects of hydrochloric acid (HCl) and acetic acid (HAc) modification on the hexadecyl trimethyl ammonium bromide (HTAB) and K+ adsorption characteristics of a natural zeolite were investigated. Electrokinetic evaluations showed that HCl had a more prominent effect on zeta potential compared to HAc. Additionally, the pH regulation behavior of the acid-modified samples was found to differ from the natural zeolite sample and it was in agreement with the results of zeta potential measurements. It was clear that the acid modification processes positively affected the surface properties and improved the cation exchange capacity (CEC) of natural zeolite. The results for the adsorption studies showed that the adsorption density of zeolite increased at elevated HTAB and K+ concentrations. Moreover, following the zeta and pH profile results, a considerable difference in the adsorption ability between natural and acid-modified zeolite samples is present in terms of HTAB and K+ adsorption characteristics. It was concluded that acid modification can be used in the enhancement of the adsorption ability of zeolites.