Surface triazine functionalization of waste-polystyrene-derived hyper-crosslinked polymers for adsorption-assisted photocatalytic degradation of tetracycline

Antibiotic residues persist in water because continuous discharge, molecular stability and the formation of bioactive transformation products cannot be eliminated by adsorption alone. Nevertheless, integrating pollutant enrichment with in situ photocatalytic conversion in a single material remains difficult because suspension photocatalysis is hindered by weak interfacial affinity, short radical lifetimes, and the spatial mismatch between adsorbed pollutants and photoactive domains. Herein, we knit triazine units into waste-plastic-derived hyper-crosslinked polymers (HCP-Ns) to couple microporous enrichment with visible-light-driven tetracycline (TC) oxidation, in which the HCP skeleton supplies the enrichment microenvironment while triazine domains concurrently tune the porous architecture, narrow the optical band gap, and accelerate interfacial charge transfer to drive oxygen activation. The optimized HCP-N-4 combines a BET surface area of 1164.71 m 2 g -1 , a hierarchical micro/mesoporous network, and a 2.29 eV band gap, and removes 92.62% of TC at pH 6.0 with 0.15 g L -1 catalyst and 80 mg L -1 TC. LC-MS, EPR, and scavenger experiments reveal that TC transformation proceeds through adsorption-assisted demethylation, deamidation, dehydroxylation, and ring-opening routes, with ·O 2 - showing the strongest measured contribution among the reactive species probed, while ·OH and h⁺ also. This work establishes a structure-activity relationship in which triazine-regulated waste-plastic polymers unify pore enrichment, charge separation and oxygen activation, linking plastic-waste valorization to the adsorption-photocatalysis synergistic removal of antibiotics.