Photocatalytic degradation of ciprofloxacin by MMT/CuFe2O4 nanocomposite: characteristics, response surface methodology, and toxicity analyses.

Abstract

The photocatalytic degradation of ciprofloxacin (CIP) was examined by loading spinel ferrite copper (CuFe2O4) nanoparticles onto montmorillonite (MMT) under irradiation using UV light. The laboratory parameters were optimized using response surface methodology (RSM), and maximum efficiency (83.75%) was achieved at a pH of 3, CIP concentration of 32.5 mg/L, MMT/CuFe2O4 dose of 0.78 g/L, and irradiation time of 47.50 min. During the photocatalysis process, the experiments on radical trapping demonstrated the generation of hydroxyls (•OH), superoxide (•O2-) radical, electrons (e-), and holes (h+). A low rate drop (below 10%) in the CIP degradation during the six consecutive reaction cycles corroborated the remarkable recyclability and stability of the MMT/CuFe2O4. The acute toxicity of the treated solution was determined using Daphnia Magna, by applying photocatalysis, which was indicative of a marked decline in the toxicity. Comparing the findings of the degradation using UV and the degradation process using visible light represented results with close resemblance to each other at the end of the reaction time. Besides, under UV and visible light, the particles in reactor are easily activated when the pollutant mineralization exceeded 80%.