Removal of COD from Secondary Effluent Using Fenton Iron Sludge-Based Biochar/Fe(VI)/H 2 O 2 Process. - Wang, Lia; He, Xu; Liang, Lan; Wang, Yanshan; Yan, Beibei; Chen, Guanyi; Li, Ning; Hou, Li'an (Applied Sciences (2076-3417), 2025)