3D ZnO modified biochar-based hydrogels for removing U(VI) in aqueous solution

A novel three dimensional ZnO modified biochar-based hydrogel (ZBCG) was fabricated and employed for removing U(VI) in aqueous solution. The ZBCG hydrogel, the successful loading of ZnO modified biochar (ZBC) confirmed by SEM and FTIR, has showed a well mechanical characteristics, thermal stability, anti-swelling property and adsorption performance for U(VI) than pure hydrogels (BG). At T = 40 ℃, pH = 5, the maximum adsorption capacity of the Langmuir model was 239.21 mg/g. According to adsorption kinetics tests, the chemical adsorption has occupied the leading status in the adsorption process of ZBCG for U(VI). More importantly, ZBCG could be quickly separated and easily regenerated. After 5 cycles of adsorption-desorption, ZBCG have kept the uranium adsorption efficiency of 78.88%. On account of spectroscopic analyses, the mechanisms between ZBCG and U(VI) were involved ion exchange with Zn2+ and chelation by -OH and -COOH. This study proved that ZBCG could be considered the effective and promising material for U(VI) removement from an aqueous solution.