A study on the mechanism of efficient NOR degradation via peroxymonosulphate activation using Ni metal cluster/BiOBr composite catalysts

The NB-10/PMS system degrades NOR with a degradation efficiency of over 96%. • •O 2 - and 1 O 2 dominate; non-radical pathway plays key role. • SO 4 •− and •OH play a supporting role, assisting in the degradation of NOR • Anti-interference to coexisting ions, efficient in natural water. To address the issues of efficient removal of antibiotic pollutants and the limited activation efficiency of peroxomonosulphate (PMS), this study developed a Ni metal cluster-modified bismuth bromide (Ni/BiOBr) composite catalyst and utilised it to activate PMS for the degradation of norfloxacin (NOR) in water. By regulating the interfacial interactions between the Ni metal clusters and BiOBr, interfacial electron transfer was promoted and the PMS activation efficiency was enhanced. The results indicate that the Ni/BiOBr-PMS system exhibits excellent NOR removal performance, with a NOR degradation rate of up to 96.7% within 60 min. Material characterisation results show that the introduction of Ni clusters provides abundant reactive sites and improves the interfacial electron transfer properties of the composite material. Radical quenching experiments and electron paramagnetic resonance (EPR) analysis indicated that various reactive oxygen species, including SO 4 •- , •OH and 1 O 2 , are generated within the system and collectively participate in the oxidative degradation of NOR. Electrochemical testing further confirmed that Ni/BiOBr possesses good electron transfer capability, which is conducive to the sustained activation of PMS. Furthermore, this catalytic system demonstrates good adaptability under different reaction conditions and in the presence of various co-existing anions, whilst exhibiting good cycling stability. The results indicate that regulating the electron transfer process via the Ni metal cluster/BiOBr interface can effectively enhance PMS activation, providing new insights into the design of metal cluster-based PMS catalytic materials and the treatment of antibiotic-contaminated water. Download: Download high-res image (226KB) Download: Download full-size image