Montmorillonite-modified stabilizing SA/CMC gel spheres cross-linked by lanthanum for tetracycline hydrochloride removal

Abstract

In this study, a stable gel sphere was successfully prepared by crosslinking sodium alginate(SA) with sodium carboxymethyl cellulose(CMC) through La and modified by MMT for removing tetracycline hydrochloride (TCH). The obtained materials have been comprehensively characterized using SEM, FTIR, XRD and XPS. The results of batch experiments showed that La@SA/CMC-MMT-0.5 had a high adsorption capacity of TCH, and its maximum adsorption capacity was up to 420.95 mg/g. The adsorption process followed a pseudo-second-order kinetic model and the Freundlich isotherm model. The removal of TCH was a combined process involving both chemisorption and physical adsorption. Hydrogen-bond and complexation played a primary role in removing process, while the role of static electricity was more limited. The MMT modification not only enhanced adsorption capacity of TCH but also improved the thermal stability of the material by creating a temperature barrier and promoting hydrogen-bond. La substitution of metal ions in MMT and electrostatic attraction by MMT-surface negative charges contributed to reducing La-release. In application experiments, the La@SA/CMC-MMT-0.5 showed a high adsorption capacity, strong anti-disturbance performance, and good reusability. Therefore, La@SA/CMC-MMT-0.5 holds great potential for the effective adsorption of TCH in aqueous environments.