Peroxymonosulfate-assisted g-C3N4@Bi2MoO6 photocatalytic system for degradation of nimesulide through phenyl ether bond cleavage under visible light irradiation

Abstract

Non-steroidal anti-inflammatory drugs (NSAIDs) are a kind of emerging pollutants that have caused people's concerns. In this work, the catalytic system with perovskite-like material Bi2MoO6 modified graphitic carbon nitride (g-C3N4) combined with peroxymonosulfate (PMS) was constructed to efficiently degrade nimesulide (NIM) in water. After the characterization by various technologies, it was found that the g-C3N4 @ Bi2MoO6 composite possessed an increased specific surface area, enhanced light absorption range, and lower recombination rate of the photogenerated carriers. Thereby the composites displayed stronger photocatalytic activity than pure g-C3N4 and Bi2MoO6. The introduction of PMS not only provided more reactive oxygen species (ROSs) for the photocatalytic system, such as SO4− and 1O2 but also further promoted the transfer of photogenerated electrons. The multiple active species that existed in the system were involved in the photocatalytic process so that 97.4% NIM was degraded with 12 min. The degradation path of NIM was analyzed by LC-MS detection, which revealed that the structure of NIM was decomposed by the cleavage of the phenyl ether bond. The detection results of the total organic carbon (TOC) indicated that the proposed method could enhance the mineralization efficiency of NIM. This work could propose a solution for the rapid removal and degradation of NSAIDs in water.