Amphoteric cellulose microspheres for the efficient remediation of anionic and cationic dyeing wastewater

[Display omitted] •Amphoteric cellulose microsphere (ACM) contains both carboxyl and amino groups.•ACM displayed hierarchic porous network structures and high specific surface areas.•ACM could simultaneously remove both cationic and anionic dyes.•ACM could effectively treat actual dyeing wastewater. Amphoteric cellulose porous microsphere adsorbents (ACM) with high contents of functional groups were prepared by carboxylation and amination reactions. The obtained ACM possess similar contents of carboxyl groups (1.52 mmol/g) and amino groups (1.51 mmol/g). In addition, the modified microspheres exhibited excellent mechanical properties benefiting from the dense porous structures. The ACM could simultaneously remove the cationic dye methyl orange (MO) as well as the anionic dye methylene blue (MeB) with adsorption capacities as high as 345.32 mg/g and 616.12 mg/g, respectively. Another the microspheres are also with good regeneration that the adsorption capacities still maintained more than 90 % after 8 cycles.