Effective removal of Basic Red 12 dye by novel antimicrobial trimellitic anhydride isothiocyanate-cross-linked chitosan hydrogels

Abstract

Dyes removal from wastewater of industries is considered the prime demand of the environment. Three trimellitic anhydride isothiocyanate-cross-linked chitosan hydrogels, previously reported as novel antimicrobial agents, were investigated for the first time in this work as adsorbents for Basic Red 12 (BR 12) cationic dye. These hydrogels behave as polyanionic materials. Their adsorption capacity for the BR 12 dye increased significantly with increasing both the temperature, the solution pH and their cross-linking content. Their adsorption fitted to the pseudo-second-order kinetic model. Their adsorption isotherms conform to the Langmuir model suggesting that the adsorption nature is a monolayer having an optimum sorption capability of 38.27 mg g−1 and removal efficiency of 97.38%. The results proved that the adsorption process is remarkably proceeded by chemisorption phenomenon. The data of adsorption thermodynamics indicate that the adsorption is an endothermic process. The regeneration and reuse of the hydrogels were possible. Thus, incorporation of the functionality of the cross-linker into chitosan within the same structure efficiently enhanced its features. It is a good manner for achieving appropriate series of efficient adsorbents which are considered as favorable nominees in the field of basic dyes removal.