Ionic liquids grafted regenerated cellulose aerogel for efficient adsorption of antibiotics and dyes in wastewater

Abstract

In this study, regenerated cellulose aerogels were successfully fabricated using salix-derived cellulose dissolved in a simple alkali/urea aqueous system, followed by a secondary solubilization and functionalization step involving ionic liquids. This dual-solvent approach significantly improved cellulose dissolution and introduced additional active sites for adsorption. The cellulose solutions were gelled using a metal-ion coagulation bath combined with an acrylamide polymerization system, forming stable three-dimensional porous aerogels. The resulting aerogels were applied to remove multiple classes of organic pollutants, including antibiotics and both cationic and anionic dyes from wastewater. Adsorption experiments were carried out to evaluate the influence of pollutant concentration, adsorbent dosage, pH, temperature, and coexisting ions on performance. The aerogels exhibited rapid adsorption kinetics, achieving equilibrium within 30 min, and demonstrated high adsorption capacities for tetracycline (TC, 256.6 mg/g), methylene blue (MB, 218.7 mg/g), and alizarin red S (ARS, 384.4 mg/g). Furthermore, after five adsorption–desorption cycles, the aerogels retained more than 75% of their initial adsorption capacity, indicating strong reusability. Compared with other reported adsorbents, the aerogels displayed superior performance in terms of adsorption efficiency, versatility, and recyclability, highlighting their practical potential for sustainable wastewater treatment.