Perfluorooctanoic　acid　(PFOA)　remains　a　persistent　organic　pollutant　within　aquatic　ecosystems.　Activated　persulfate　(PS)　technology　has　been　widely　used　because　it　can　effectively　destroy　the　stable　structure　of　PFOA.　However,　this　technology　still　has　some　restrictive　problems,　such　as　the　large　amount　of　PS　required　for　the　reaction　and　the　high　SO42-　concentration　in　the　wastewater　after　the　reaction.　In　this　study,　we　used　the　advantages　of　hydrodynamic　cavitation　to　activate　PS,　such　as　promoting　mass　transfer　and　oxidant　utilization.　After　3　hours　of　treatment,　the　HC/PS　system　showed　outstanding　performance　in　that　93.6%　of　PFOA　was　degraded,　and　31.09%　of　PFOA　was　defluorinated　under　optimal　conditions　with　smaller　PS　dosage　and　lesser　SO42-　generation.　The　different　inhibitory　effects　of　coexisting　substances　(Cl-,　CO32-,　F-,　NO3-,　SO42-,　HA)　on　the　system　were　emphasized.　The　contribution　rates　of　sulfate　radicals　(SO4•-,　84.4%)　and　hydroxyl　radicals　(·OH,　10.9%),　which　are　the　main　active　substances　in　the　HC/PS　system,　were　calculated　during　the　degradation　of　PFOA.　The　potential　degradation　pathways　of　PFOA　were　proposed　based　on　the　intermediates　identified　through　LC-MS/MS.　PFOA　gradually　lost　CF2　units,　forming　shorter-chain　intermediates　(PFHpA,　PFHxA,　PFPeA,　PFBA)　and　F-,　ultimately　converting　to　H2O　and　CO2.　Above　all,　this　study　provides　valuable　insights　into　the　future　wastewater　treatment　process　for　PFOA　pollution　and　has　important　guiding　significance　for　practical　engineering　applications.　©　2024　Elsevier　Ltd