Convenient fabrication of ultrafine VOx decorated on porous g-C3N4 for boosting photocatalytic degradation of pharmaceuticals with peroxymonosulfate

Abstract

While VOx-based catalysts attracted extensive attention as Fenton-like catalysts for organic transformations, they remain underutilized in the area of the wastewater treatment by coupling photocatalysis with peroxymonosulfate (PMS) oxidation. Herein, we report VOx sites anchored on porous g-C3N4 that functions as a reusable heterogeneous photocatalyst for the efficient activation of PMS to decompose and mineralize pharmaceuticals in water. The VOx hybrid nanomaterials were synthesized by a facile and cheap route via a thermal polymerization and mild ammonium metavanadate decomposition process, which successfully immobilized ultrafine VOx on the porous carbon nitride. Systematic characterizations displayed that the interaction of VOx clusters and porous g-C3N4 could effectively speed up the charge carriers separation and restrain the recombination of photoexcitons. The ultrafine VOx species offered abundant active sites for PMS activation to produce active radicals under light, which had strong oxidating ability to degrade pharmaceutical pollutions. The V(V)/V(IV) recycle also ensured the continuous production of reactive oxygen species (ROS). Owing to these merits, VOx-based catalysts presented outstanding catalytic activity and stability in the pharmaceuticals decomposition with PMS and simulated sunlight. The removal rate of carbamazepine (CBZ) can reach >99% within 15 min in the PMS system with 8%VOx@CN catalyst under optimized conditions, nearly 12.8 times as much as unmodified g-C3N4. This study offers a promising candidate to efficiently eliminate organic pharmaceuticals in wastewater, which is suitable for practical application.