Aging of Polystyrene Micro/Nanoplastics Enhances Cephalosporin Phototransformation via Structure-Sensitive Interfacial Hydrogen Bonding

Fourier transform infrared spectroscopy, batch adsorption experiments, and theoretical calculations underscored that the structure-dependent enhancement stemmed from the specific hydrogen bonding sites, rather than mere adsorption capacity. Specifically, the -OOH group (hydroperoxyl group) on the PS surface exhibited a greater potential to generate OH• compared to the -OH group. Therefore, cephalosporins that formed hydrogen bonds with -OOH moieties on the aged PS surfaces, as opposed to -OH, would experience a more pronounced degradation enhancement. Thus, the unique interaction pattern between contaminants and PS-M/NPs transforms aged PS into a selective reactor, facilitating the targeted degradation of pharmaceuticals in aquatic ecosystems.