In　this　study,　a　novel　magnetic　biochar　(BC-Fe-n),　synthesized　by　one-step　pyrolysis　at　800　degrees　C　using　platanus　leaves　and　iron-containing　sludge　in　different　mass　ratios,　was　used　to　activate　persulfate　(PS)　for　tetracycline　(TC)　degradation.　Results　show　that　BC-Fe-1:2　exhibited　excellent　degradation　performance　(91.4%),　much　better　than　the　raw　biochar　(BC)　(77.1%).　And　electron　paramagnetic　resonance　(EPR)　techniques　demonstrated　radical　(SO4　center　dot-,　center　dot　OH,　O-2(center　dot-))　and　non-radical　(O-1(2))　pathways　in　BC-Fe-1:2/PS,　S　O4(center　dot-)　was　further　proved　to　be　the　main　active　species　by　quenching　experiments.　Liquid　chromatography-mass　spectrometry　(LC-MS)　was　utilized　to　identify　the　intermediates　of　TC　and　three　possible　degradation　pathways　were　proposed.　Additionally,　the　BC-Fe-1:2　was　weakly　affected　by　pH　and　the　coexisting　anions　in　wastewater,　and　could　still　remove　80%　of　TC　in　the　third　cycle　experiment.　This　study　provides　a　new　idea　for　converting　backwash　iron-containing　sludge　from　groundwater　treatment　plants　into　valuable　catalysts,　and　provides　new　insights　into　the　key　role　of　low-cost　magnetic　biochar　in　PS　activation.