A　new　type　of　catalyst　based　on　electrolytic　manganese　anode　slime　(EMAS)　for　heterogeneous　peroxymonosulfate　(PMS)　activation　in　acetaminophen　(APAP)　degradation　was　prepared.　The　EMAS　was　modified　by　washing,　pickling,　and　calcination　to　produce　the　DEMAS200　catalyst,　and　multi-types　of　refractory　organic　matter　could　be　degraded　by　the　DEMAS200/PMS　system,　of　which　20　mg/L　APAP　can　be　removed　within　4　min.　A　radical　activation　mechanism　based　on　PMS　was　proposed　through　a　series　of　APAP　degradation　experiments　and　material　characterization.　By　quenching,　probing,　PMSO　experiments,　and　electron　paramagnetic　resonance　(EPR),　the　major　contribution　of　various　reactive　oxygen　species　(ROS)　(such　as　·OHfree,　SO4·−,　high-valent　Mn　species,　1O2　and　O2·−)　was　excluded,　and　·OHads　was　verified　as　the　major　ROS.　Nuclear　magnetic　resonance　(NMR)　was　applied　to　identify　active　hydrogen　using　the　D2O　exchange　method　to　qualitatively　identify　the　presence　of　·OHads,　which　was　determined　by　comparing　the　appearance　and　disappearance　of　chemical　shifts　at　1.90　ppm　(active　hydrogen)　and　7.96　ppm　(hydrogen　at　the　benzene　ring　on　TPA).　In　this　study,　the　modified　EMAS　was　innovatively　introduced　for　PMS　activation　in　the　degradation　of　APAP,　and　NMR　technology　successfully　identified　the　presence　of　different　hydroxyls.　©　2024　Elsevier　B.V.