Magnetic Hierarchical Photocatalytic Nanoreactors: Toward Highly Selective Cd2+ Removal with Secondary Pollution Free Tetracycline Degradation

In the present work, a new type of ecofriendly and recyclable magnetic hierarchical porous Cd2+ imprinted photocatalytic nanoreactors (MHP-Cd) are developed by utilizing the ion imprinting technique. Owing to numerous Cd2+ cavities generation and corresponding high adsorption capacity of Cd2+ of 154.99 mg/g in the imprinted layer, the as-prepared nanoreactors exhibit excellent selectivity of Cd2+ adsorption under corroboration of enhanced kon, of Cd2+ to other ions [Icions(Cd2+/Fe3+) = 2.836, Icions(Cd-2/Cu2+) = 2.303, and kions(Cd2+/Zn2+) = 3.064]. Importantly, with coexistence of mesoporous and sodium pyrrolidone carboxylate, i.e., light transmittance materials, toxic tetracycline can easily contact with CdS and most of the light is amenable to being adsorbed by CdS, consequently promoting higher photocatalytic activity for degradation of tetracycline (i.e., degradation rate reaches 75.32%). Such developed MHP-Cd photocatalysts demonstrate a highly selective adsorption of Cd2+ and simultaneous tetracycline degradation with effective inhibition of the secondary pollution. With a promoted stability for recycling, our work provides a new promising technique for environment friendly selective adsorption of targeted heavy metal ions and synchronous degradation of antibiotic containment in mixed water environments.