Fabrication of Bi/BiOCOOH/PVDF with improved photocatalytic activity for the degradation of ciprofloxacin

The development of a low-cost and recyclable method for wastewater treatment has been a major challenge. Polyvinylidene fluoride (PVDF) membranes have received considerable attention owing to their excellent mechanical strength, unique antioxidant properties, and low cost. In this study, Bi/BiOCOOH/PVDF composite membrane materials were prepared using a simple two-step solvent thermal method and phase conversion method. The results showed that under the synergistic action of adsorption and photocatalysis, the photocatalytic degradation efficiency of Bi/BiOCOOH composite material and Bi/BiOCOOH/PVDF composite membrane material for ciprofloxacin (CIP) was much higher than that of BiOCOOH. The introduction of PVDF acted as a carrier, improved the adsorption of the catalytic material to CIP, and facilitated the effective collision of the photocatalytic active site and CIP. The experimental results and theoretical calculations confirmed that the combination of Bi and BiOCOOH effectively improved the light absorption capacity and photocatalytic performance. The reproducibility test revealed that the small amount of new composite catalyst for Bi/BiOCOOH/PVDF as a carrier was lost and that the Bi/BiOCOOH/PVDF catalyst still had high catalytic activity. In addition, the influence of water matrix factors, such as pH and anion, on the photocatalytic degradation experiment was investigated, which would provide some reference for the actual wastewater treatment of the composite catalyst. This study demonstrates a photocatalytic activation mechanism between metals and semiconductors and provides some basis for constructing catalysts for the synergistic and effective treatment of water pollution through a combined adsorption and photocatalysis process.