Sorption of antimonate by HDTMA-modified zeolite

Cationic surfactants have been found in previous studies to enhance the capacity of zeolites to bind organic compounds and oxyanions. In this study, we treated zeolite with hexadecyltrimethylammonium (HDTMA) and studied the sorption of antimonate by the modified zeolite. During the modification, the zeolite sorbed more than 94% of HDTMA initially present in different treatment solutions. Desorption of HDTMA from the zeolite was less than 15% in total after threefold washing with distilled water.Antimonate binding was most effective when the zeolite was treated with HDTMA solutions exceeding the zeolites external cation exchange capacity. A modified Langmuir-type isotherm was developed to describe HDTMA sorption onto zeolite. Antimonate sorption on modified zeolite was best described by Langmuir isotherms. HDTMA-zeolite in aqueous suspension (50 g/l) sorbed up to 42% of antimonate from solutions containing from 0.09 to 2.15 mmol/l Sb.