Efficient degradation of ciprofloxacin by Co3O4/Si nanoarrays heterojunction activated peroxymonosulfate under simulated sunlight: Performance and mechanism

The development of stable and efficient photocatalysts to activate peroxo monosulfate (PMS) is of great significance in water treatment, but it is still a major challenge. In this paper, Co3O4/Si nanoarrays (Co3O4/SiNWs) heterojunction is successfully synthesized through simple and effective approaches, and the peroxymonosulfate (PMS) assisted photocatalytic degradation system based on the Co3O4/SiNWs heterojunction under simulated sunlight is constructed for ciprofloxacin (CIP) degradation. The Co3O4/SiNWs-30/PMS system exhibits a high CIP photocatalytic degradation rate of 93.51% and a kinetic constant of 0.0474 min(-1) in 60 min accompanied with good degradation stability. The appropriate energy band structure of Co3O4/SiNWs heterojunction allow the formation of internal electric field, resulting in the establishment of a typical Z-scheme charge transfer system. On the one hand, the formed Co3O4/SiNWs Z-scheme heterojunction can synchronously inhibit the recombination of photo-generated electron-hole (e(-)-h(+)), which promotes the transfer of photogenerated carriers and improve the photocatalytic activity. On the other hand, photogenerated e- contribute to produce active radicals by activating PMS, and photogenerated h(+) can also be directly used as active radicals, thereby realizing high -efficiency photocatalytic degradation. This work gives a good insight into the photocatalytic degradation of antibiotics in water.

Automated summary

The development of stable and efficient photocatalysts for activating peroxo monosulfate (PMS) is crucial in water treatment. This study successfully synthesized Co3O4/Si nanoarrays heterojunction and constructed a PMS-assisted photocatalytic degradation system for ciprofloxacin degradation. The Co3O4/SiNWs-30/PMS system exhibited high degradation efficiency and stability. The appropriate energy band structure of the Co3O4/SiNWs heterojunction allowed the establishment of a Z-scheme charge transfer system, leading to enhanced photocatalytic activity.