Recent development of sludge biochar-based catalysts in advanced oxidation processes for removing wastewater contaminants: A review

•Sewage sludge conversion into sludge biochar as catalysts are reviewed.•Modification methods of SBCs are discussed.•Application of SBCs in AOPs to remove pollutants in water is summarized.•Mechanism by which SBCs catalytic oxidation processes is analyzed.•SBCs show high performance as catalytic materials.