Ultrasonic　(US)　was　used　to　activate　persulfate　(PS)　in　presence　of　nanoscale　zero-valent　iron　(nZVI)　to　degrade　chloramphenicol　(CAP)　in　solution.　Synergistic　effects　were　observed　of　US　and　nZVI　on　PS　activation　(US-nZVI/PS)　compared　to　US/PS,　nZVI/PS,　or　US-nZVI　alone,　while　replacement　of　nZVI　with　Fe(II)　or　Fe(III)　ion　was　less　efficient　to　degrade　CAP.　The　US-nZVI/PS　treatment　exhibited　a　rapid　and　continuous　oxidation　of　CAP　in　solution.　Both　(OH)-O-center　dot　and　SO4　center　dot-　were　considered　to　be　primary　reactive　species　responsible　for　CAP　degradation,　of　which　SO4　center　dot-　had　a　higher　contribution　than　(OH)-O-center　dot.　Our　results　indicated　that　Fe2+　was　continuously　being　recycled　by　reaction　of　nZVI　and　PS,　accompanied　by　generation　of　SO4　center　dot-.　US　accelerated　the　corrosion　of　nZVI　and　removed　passive　films　on　the　nZVI　surface.　Under　optimal　conditions,　98.1%　of　CAP　was　degraded　during　90　min.　This　was　established　in　presence　of　0.5　g/L　nZVI　and　1.0　mM　PS,　with　an　US　intensity　of　0.36　W/mL　at　40　kHz　and　a　pH　of　7.0.　When　present,　inorganic　anions　and　natural　organic　matter　partly　inhibited　CAP　degradation,　which　was　mainly　attributed　to　their　scavenging　effects　for　SO4　center　dot-　and　(OH)-O-center　dot.　The　reusability　of　nZVI　was　examined　in　five　consecutive　cycles,　showing　a　decrease　in　efficiency　with　each　cycle.　Seven　major　intermediate　products　were　identified,　and　these　indicated　two　degradation　pathways.　Finally,　in-situ　regeneration　of　CAP-saturated　powdered　activated　carbon　using　US-nZVI/PS　process　was　evaluated.