Carboxyl-functionalized graphene oxide/cellulose nanofiber as adsorbents toward methylene blue

An efficient adsorbent for eliminating methylene blue (MB) from water solutions was created by combining carboxyl-functionalized graphene oxide (GO-COOH) with cellulose nanofiber. The GO-COOH was prepared using a malonic acid-choline chloride deep eutectic solvent, resulting in a carboxyl group ratio of 5.3 % and a C/O ratio of 2.15. This novel approach addresses the issue of partial reduction of GO-COOH observed in traditional preparation methods, thereby enhancing the adsorption capacity of the adsorbent for MB (611.44 mg g-1). In general, this method provides the opportunity for producing cellulose-based adsorbents for dye wastewater on a large scale, while being environmentally friendly.