Multifunctional Cross-Linked Shrimp Waste-Derived Chitosan/MgAl-LDH Composite for Removal of As(V) from Wastewater and Antibacterial Activity.

Abstract

This work synthesized a novel chitosan-loaded MgAl-LDH (LDH = layered double hyroxide) nanocomposite, which was physicochemically characterized, and its performance in As(V) removal and antimicrobial activity was evaluated. Chitosan-loaded MgAl-LDH nanocomposite (CsC@MgAl-LDH) was prepared using cross-linked natural chitosan from shrimp waste and modified by Mg-Al. The main mechanisms predominating the separation of As(V) were elucidated. The characteristic changes confirming MgAl-LDH modification with chitosan were analyzed through Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis-differential thermal analysis, and Brunauer-Emmett-Teller measurements. Porosity and the increased surface area play an important role in arsenic adsorption and microbial activity. Adsorption kinetics follows the general order statistically confirmed by Bayesian Information Criterion differences. To understand the adsorption process, Langmuir, Freundlich, and Liu isotherms were studied at three different temperatures. It was found that Liu's isotherm model was the best-fitted model. CsC@MgAl-LDH showed the maximum adsorption capacity of 69.29 mg g-1 toward arsenic at 60 °C. It was observed that the adsorption capacity of the material rose with the increase in temperature. The spontaneous behavior and endothermic nature of adsorption was confirmed by the thermodynamic parameters study. Minimal change in percentage removal was observed with coexisting ions. The regeneration of material and adsorption-desorption cycles revealed that the adsorbent is economically efficient. The nanocomposite was very effective against Staphylococcus aureus and Bacillus subtilus.