Xanthated chitosan/cellulose sponges for the efficient removal of anionic and cationic dyes

Biomass can adsorb dyes and then degrade. Although this material has remarkable prospects, its application is limited by its adsorption capacity and the simultaneous adsorption of cations/anions. Herein, a pore-forming agent in a solvent exchange phase transformation was used to fabricate chitosan xanthate and cellulose xanthate (xanthated chitosan/cellulose) sponges. Owing to the hierarchical pores and the presence of xanthic acid and amino groups, the sponges show efficient removal ability for anionic (congo red) and cationic (methylene blue) dyes. The adsorption mechanism, isotherm, kinetics, and thermodynamics were comprehensively studied. The xanthated chitosan/cellulose sponges exhibited the maximum adsorption capacities of 213.220 and 289.855 mg g−1 toward methylene blue and Congo red, respectively. The mechanism is a spontaneous physic-sorption process that fitted well with the pseudo-second-order and Langmuir isotherm models. These results revealed that xanthated chitosan/cellulose sponges are effective adsorbents for the removal of methylene blue and Congo red dyes and provide a new platform for dye decontamination.