Aging Mechanism of Microplastics in UV/Persulfate System and Its Effect on Norfloxacin Adsorption Behavior

• • UV+KPS aging increased PS adsorption capacity for norfloxacin to (2.539±0.032) mg·g−1, a 4.20-fold enhancement over pristine PS, attributed to increased specific surface area and oxygen-containing functional groups, which is critical for predicting contaminant mobility in AOP-treated wastewater. • • The aging process generated oxygen-centered environmentally persistent free radicals (EPFRs), a class of emerging contaminants with potential toxicological implications, underscoring the need for risk assessment of AOP-treated microplastics. • • UV+KPS produced higher yields of ROS (·OH, SO4·−, O2·−, 1O2) compared to UV alone, accelerating PS aging as evidenced by yellowing, increased roughness, and surface charge changes, demonstrating the synergistic effect of persulfate activation. • • Adsorption kinetics followed pseudo-second-order model and isotherms fitted Langmuir model, indicating monolayer chemisorption; pH significantly influenced adsorption via electrostatic interactions, providing operational parameters for optimizing NOR removal in water treatment.