Composite heterojunctions effectively enhance the separation efficiency of photoelectrons and holes, thereby activating the peroxymonosulfate (PMS) process to degrade recalcitrant pollutants. Consequently, a g-C3N4/CuFe2O4/MnO2 (CN/CFO/MN) composite with a dual Z-scheme heterojunction was developed for the first time and coupled with PMS for the degradation of ciprofloxacin. CN/CFO/MN exhibited strong binding ability to ciprofloxacin with an adsorption capacity of 38mg/g, reaching adsorption equilibrium within 60min with high efficiency, which is crucial for effective degradation. Additionally, isolated CN/CFO/MN and bare PMS (0.3g/L) demonstrated limited degradation capabilities with ciprofloxacin removal rate of 51% and 41% under illumination, respectively. Notably, the elimination efficiency of ciprofloxacin was enhanced to nearly 100% by integrating CN/CFO/MN photodegradation with PMS activation. Furthermore, compared to pure CN, CFO, MN, and the binary CN/CFO, CN/CFO/MN provided superior photocatalytic degradation, improving the removal efficiency from 45% to 63%. The dual Z-scheme heterojunction in CN/CFO/MN furnishes ample photoelectrons to activate the PMS process for the generation of free radicals. Active species exploration experiments suggest that the CN/CFO/MN-PMS-light method primarily degrades ciprofloxacin by catalyzing the generation of holes, superoxide, hydroxyl and sulfate radicals. The CN/CFO/MN-PMS-light method achieved complete removal of 0.02–0.1g/L ciprofloxacin within 5min in tap, pond and river water systems. Ultra-performance liquid chromatography-mass spectrometry analysis-determined the degradation pathways of ciprofloxacin to involve the piperazine ring, defluorination reaction, and oxidation reaction of quinolone. Assessment via toxicity estimation software indicated that the toxicity of the degradation products was significantly reduced reaching harmless level. This work demonstrates that the CN/CFO/MN-PMS-light method with a dual Z-scheme heterojunction holds considerable potential for environmental purification.
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