Bentonite modified with cationic surfactant as promissing adsorbent for carbamazepine

Abstract

Numerous chemical compounds present in natural waters and wastewater are resistant to conventional water treatments and persist in treated effluents. Among these substances, pharmaceuticals, due to their widespread use, raise special concern due to their potentially harmful effects on human health especially when they reach drinking water. One of the most efficient technique for removal of pharmaceuticals from polluted water is their adsorption on various adsorbents, such as activated carbons, clays (kaolin, bentonite, etc.) and zeolites. In this study, the potential of modified bentonite for removal of carbamazepine, a pharmaceutical with anticonvulsant and mood-stabilizing properties, was investigated. The natural bentonite from Šipovo deposit, Bosnia and Herzegovina, was modified with the cationic surfactant Arquad®2HT-75 in amounts equivalent to 50% and 100% of the bentonite's cationic exchange capacity. Characterization of prepared samples by Fouriertransform infrared spectroscopy and Simultaneous Thermal Analysis, confirmed presence of surfactant in modified bentonites. Results on carbamazepine removal by modified bentonites showed that its adsorption increased with increasing of the amount of surfactant as well as with increasing of the initial pharmaceutical concentration. The highest adsorption of carbamazepine was achieved with bentonite containing the highest amount of surfactant. Since the natural bentonite has no affinity to remove carbamazepine, these findings suggest that modified bentonite is a promising adsorbent for its removal from contaminated water.