A novel PVDF film containing g-C3N4@MOF composite for efficient photoreduction of Cr(VI) under visible light

In this study, g-C₃N₄ was successfully synthesized and combined with MIL-88A to form a composite material (g-C₃N₄@MIL-88A composite, abbreviated as CNM). With the aid of the phase inversion method, CNM-PVDF composite films were synthesized, integrating various functional components. The CNM Z-scheme heterojunction efficiently harvests visible light, enhances interfacial separation, and suppresses the recombination of photogenerated charge carriers, resulting in significant photoreduction of Cr(VI) (94.01%). However, CNM composites in powder form tend to aggregate without stable support, complicating separation and recycling processes. To address this issue, PVDF is used to immobilize the photocatalyst. The results demonstrate that CNM-PVDF films exhibit superior photocatalytic reduction activity towards Cr(VI), achieving an efficiency of 90.4% under optimal conditions: 20 mg/L of Cr(VI), 3% CNM-PVDF, pH 3, and 180 min of irradiation. This study represents a significant advancement in developing and applying composite films, offering excellent photocatalytic performance. Unlike the powder sample (CNM), the CNM-PVDF composite can be easily recovered for four consecutive cycles, effectively overcoming the challenge of secondary pollution.