Efficient adsorption‐photocatalysis activity of ternary ZnO‐Sm2O3‐MgO co‐modified biochar for dye removal

To boost the adsorption‐photocatalytic performances of biochar in wastewater treatment, biochar was modified with ternary metal oxides ZnO, Sm 2 O 3 , and MgO (ZnSm/Mg‐biochar) via the one‐step pyrolysis method. The optimal 2b‐ZnSm/Mg‐biochar with a Zn/Sm molar ratio of 1:1 exhibited the better removal activity of RhB in comparison with biochar, 2‐Mg/biochar, and b‐ZnSm/biochar. The removal efficiency and adsorption capacity of 2b‐ZnSm/Mg‐biochar was 99.46% and 979.22 mg g −1 for RhB solution of 410 mg g −1 , respectively. The adsorption kinetics and isotherms of ZnSm/Mg‐biochar composites were as described by second‐order and Langmuir models, respectively. The abundant vacant sites at the junction interface of ZnO, Sm 2 O 3 , MgO, and biochar were favorable for the adsorption and photon capturing, achieving the efficient photo‐conversion of RhB under the stimulated solar‐light irradiation.