The　intricate　composition　of　real-world　aquatic　systems　significantly　constrains　the　improved　overall　performance　of　powder　catalysts,　meanwhile　their　recyclability　is　inferior　to　the　bulk　counterparts　(e.g.　aerogels).　Herein,　by　loading　BiOBr　onto　g-C3N4　nanosheets　and　combining　them　with　agarose,　an　S-scheme　heterojunction　aerogel　(abbreviated　as　BCA)　was　synthesized,　whose　structure　was　confirmed　by　the　density　functional　theory　calculation.　Importantly,　the　BCA　could　activate　peroxymonosulfate　(PMS)　under　simulated　sunlight　for　degrading　multi-pollutant.　And　the　BCA/PMS/Light　system　efficiently　degraded　various　organic　contaminants　in　aqueous　environments,　achieving　a　high　degradation　rate　constant　of　0.1503　min−1　for　rhodamine　B　(RhB),　significantly　surpassing　the　performance　of　CA/PMS/Light　(0.0378　min−1)　and　BCA/PMS　(0.0763　min−1)　systems.　Free　radical　quenching　experiment　and　electron　paramagnetic　resonance　analysis　reveal　that　1O2,　•O2–,　•OH　and　SO4•−　in　the　BCA/PMS/Light　system　were　pivotal　in　RhB　degradation,　with　a　dominant　non-radical　mechanism.　Additionally,　Fukui　function　analysis　pinpointed　the　primary　reaction　sites　within　the　RhB　molecule.　The　photocatalytic　heterojunction　aerogel　exhibits　outstanding　stability,　environmental　sustainability　and　versatility,　which　can　guide　the　development　of　simulated　sunlight-driven　PMS　activation　for　multi-pollutant　degradation,　catering　for　scalable　water　treatment　applications.　©　2025　Elsevier　Inc.