Performance and mechanism of CuFe2O4/2D-V to activate persulfate for levofloxacin removal

Abstract

Supported catalysts have gradually become a research hotspot in the field of removing antibiotics from wastewater. In this study, CuFe₂O₄@2D-V composite catalyst was prepared by basic hydrothermal synthesis. Two-dimensional expanded vermiculite (2D-V) was prepared by high temperature and ultrasonic stripping to provide a loading platform for CuFe₂O₄ metal ions. The characterization of CuFe₂O₄@2D-V was analysis by SEM, XRD and EDS. Then, levofloxacin (LVX) was chosen as representative to investigate the catalytic performance of CuFe₂O₄@2D-V by persulfate (PMS) activation. The optimal preparation conditions of CuFe₂O₄@2D-V and operating parameters of activating PMS to remove LVX were also studied. The result showed that under the condition of CuFe₂O₄ loading 50 %, initial pH 9.2, LVX concentration 10 mg/L, catalyst concentration 0.5 g/L and PMS concentration of 0.3 mM, the removal efficiency and reaction rate of LVX could reach 89 % and 0.071 min⁻¹, respectively. Meanwhile, the catalyst had a good stability and high reusability. Based on the analysis of intermediate products by LC-MS, three possible degradation pathways were proposed. Quenching experiments found that non-radical ${}^1{O}_2$ dominated LVX degradation process. Also, the redox reaction between Cu (I)/Cu (II) and Fe (II)/Fe (III) played an important role in LVX removal process. This work might fill the gap in the application of vermiculite as a two-dimensional carrier, and provide further understanding for antibiotic wastewater treatment by metal based two-dimensional composite materials.