Synergistic naproxen adsorption and peroxymonosulfate-driven oxidation on defective magnetic porous graphene dual functional materials

Abstract

In this study, recycled and highly active magnetic porous graphene (MPG) was prepared through defect treatment of graphene-based materials and the loading of magnetic nanoparticles. A coupling technology of adsorption and peroxymonosulfate advanced oxidation was established to remove Naproxen (NPX) from water by utilizing the excellent defect structure and abundant active sites of MPG. The removal efficiency of NPX using the MPG/PMS system was 100% within 120 min, in which the adsorption stage took 30 min and contributed 70.3% to the removal of NPX. Subsequently, the reaction rate constant reached the maximum value of 0.782 min−1 in the first minute of the chemical reaction stage after adding PMS. Quenching and EPR analysis confirmed that both free radicals (O2·-, SO4·- and·OH) and nonfree radicals (1O2) generated in the MPG/PMS system participated in the degradation of NPX. The electrochemical test further confirmed that the generation of nonfree radicals promoted by electron transfer played a major role, and the high chemical reaction active center was exposed due to the internal defects of MPG. The excellent anti-interference and widespread applicability of MPG have been verified. The intermediate products, degradation pathways, and toxicity changes of NPX degradation were analyzed and summarized.