Biochar　derived　from　sludge　is　recognized　for　its　sustainable　and　cost-effective　role　in　advanced　oxidation　processes,　yet　its　restricted　catalytic　capacity　poses　significant　challenges.　In　this　work,　nitrogen　(8.43　at%)　and　sulfur　(1.39　at%)　co-doped　biochar　(ML-SDBC)　featuring　a　large　surface　area　of　161.14　m2/g　was　synthesized　by　the　pyrolysis　of　sewage　sludge　and　sulfonated　lignin　without　external　dopants.　In　the　synthesis　of　ML-SDBC,　graphitic　nitrogen　and　thiophene　sulfur　were　efficiently　integrated　into　the　carbon　framework.　Furthermore,　the　resulting　biochar　notably　outperformed　sludge-derived　biochar　(SDBC)　in　activating　peroxymonosulfate　(PMS)　for　sulfadiazine　(SDZ)　degradation,　achieving　a　31.9%　higher　removal　rate　within　120　min　and　exhibiting　a　rate　constant　(kobs)　of　1.73×10−2　min−1,　effectively　tripling　the　efficiency　compared　to　that　of　SDBC-driven　processes.　The　degradation　rate　consistently　exceeded　85%　across　a　wide　pH　range　of　3–9.　Mechanistic　analysis　exhibited　that　degradation　processes　involved　radical　and　non-radical　pathways,　with　1O2　playing　a　prominent　role.　Furthermore,　density　functional　theory　(DFT)　calculations　revealed　that　the　catalytic　potential　in　ML-SDBC　would　benefit　from　the　synergistic　interaction　between　graphitic　nitrogen　and　thiophene　sulfur.　This　study　presents　a　novel　synthesis　of　heteroatom-doped　biochar　from　waste,　offering　a　sustainable　solution　to　antibiotic　pollution　and　waste　management　challenges.　©　2024　Elsevier　Ltd