Facile synthesis of trimethylammonium grafted cellulose foams with high capacity for selective adsorption of anionic dyes from water.

The increasing amount of dye discharge is imposing more stringent requirements on dye removal than ever before. In this work, a three-dimensional network structured cationic cellulose foam (CCF) with high dye adsorption capability and highly selective adsorption of anionic dyes is prepared through grafting and chemical crosslinking. It exhibits a maximum anionic dye Eosin Y (EY) adsorption capacity of 364.22 mg/g and a corresponding removal efficiency as high as 99.58 %. Besides, results indicate that the obtained CCF displays superior adsorption capability for anionic dyes, environmental adaptability, as well as high recyclability. The isothermal and kinetics of the dye adsorption highly match Langmuir and the pseudo-second-order kinetic model, suggesting that anionic dyes are absorbed on CCF through chemical and monolayer action. All these merits demonstrate a simple, feasible and effective approach for the design and fabrication of cellulose foams with selective adsorption of anionic dyes from wastewater.