Microplastics　are　widely　present　in　the　natural　environment　and　exhibit　a　strong　affinity　for　heavy　metals　in　water,　resulting　in　the　formation　of　microplastics　composite　heavy　metal　pollutants.　This　study　investigated　the　adsorption　of　heavy　metals　by　electron　beam-aged　microplastics.　For　the　first　time,　electron　beam　irradiation　was　employed　to　degrade　polypropylene,　demonstrating　its　ability　to　rapidly　age　microplastics　and　generate　a　substantial　number　of　oxygen-containing　functional　groups　on　aged　microplastics　surface.　Adsorption　experiments　revealed　that　the　maximum　adsorption　equilibrium　capacity　of　hexavalent　chromium　by　aged　microplastics　reached　9.3　mg　g−1.　The　adsorption　process　followed　second-order　kinetic　model　and　Freundlich　model,　indicating　that　the　main　processes　of　heavy　metal　adsorption　by　aged　microplastics　are　chemical　adsorption　and　multilayer　adsorption.　The　adsorption　of　heavy　metals　on　aged　microplastics　primarily　relies　on　the　electrostatic　and　chelation　effects　of　oxygen-containing　functional　groups.　The　study　results　demonstrate　that　environmental　factors,　such　as　pH,　salinity,　coexisting　metal　ions,　humic　acid,　and　water　matrix,　exert　inhibitory　effects　on　the　adsorption　of　heavy　metals　by　microplastics.　Theoretical　calculations　confirm　that　the　aging　process　of　microplastics　primarily　relies　on　hydroxyl　radicals　breaking　carbon　chains　and　forming　oxygen-containing　functional　groups　on　the　surface.　The　results　indicate　that　electron　beam　irradiation　can　simultaneously　oxidize　and　degrade　microplastics　while　reducing　hexavalent　chromium　levels　by　approximately　90%,　proposing　a　novel　method　for　treating　microplastics　composite　pollutants.　Gas　chromatography-mass　spectrometry　analysis　reveals　that　electron　beam　irradiation　can　oxidatively　degrade　microplastics　into　esters,　alcohols,　and　other　small　molecules.　This　study　proposes　an　innovative　and　efficient　approach　to　treat　both　microplastics　composite　heavy　metal　pollutants　while　elucidating　the　impact　of　environmental　factors　on　the　adsorption　of　heavy　metals　by　electron　beam-aged　microplastics.　The　aim　is　to　provide　a　theoretical　basis　and　guidance　for　controlling　microplastics　composite　pollution.　©　2024　Elsevier　Ltd