This　study　employed　electron　beam　irradiation　technology　to　develop　an　advanced　oxidation　process　and　systematically　investigated　the　aging　processes　and　mechanisms　of　polyvinyl　chloride　(PVC).　It　further　explored　the　influence　mechanisms　of　environmental　factors　on　the　formation　and　removal　of　composite　pollutants　involving　highly　toxic　microplastic　PVC.　The　findings　indicate　that　PVC　undergoes　a　series　of　aging　reactions　including　dechlorination,　hydroxylation,　and　carbonylation　during　the　aging　process,　which　under　strong　oxidation　conditions　further　proceeds　to　deoxygenation,　leading　to　fluctuating　changes　in　the　adsorption　properties　of　PVC.　Oxygen-containing　functional　groups　generated　during　aging,　particularly　carbonyl　groups,　significantly　enhance　the　adsorption　capacity　of　PVC　toward　pollutants,　with　the　adsorption　behavior　conforming　to　pseudo-second-order　kinetics　and　the　Freundlich　isotherm　model.　These　oxygen-containing　groups　have　been　demonstrated　to　facilitate　pollutant　adsorption　on　aged　PVC　through　electrostatic　interactions,　adsorption　energy,　hydrogen　bonding,　and　weak　intermolecular　forces.　Meanwhile,　environmental　factors　inhibit　pollutant　adsorption　by　occupying　adsorption　sites　on　aged　PVC　and　affect　the　removal　efficiency　of　composite　pollutants　by　altering　the　type　and　concentration　of　free　radicals.　This　study　elucidates　the　formation　and　removal　mechanisms　of　microplastic-associated　composite　pollutants,　highlights　the　critical　role　of　oxygen-containing　functional　groups　in　PVC　aging　and　adsorption　behavior,　and　provides　important　insights　into　the　environmental　behavior　and　risk　assessment　of　microplastic　contaminants.　©　2025