Enhanced photocatalytic decomposition of azo-dyes using 2D g-C3N4 nanosheet/PVDF films: Comparative analysis of immobilization methods and recyclability

Abstract

This paper reports on the development of solar-responsive photocatalytic films (CN/PVDF) for the decomposition of azo-dye wastewater. The as-synthesized films comprise the photocatalyst carbon nitride (g-C₃N₄ or CN) immobilized on the substrate polyvinylidene difluoride (PVDF) through three distinct fixation methods, i.e., blending (B), aperture blending (AB), and hot pressing (HP). This study investigates the characteristics of these films, evaluates their photocatalytic activity for the decolorization of acid red 1 (AR1) under simulated solar irradiation, and assesses their recycling potential. Experimentation on the AR1 decolorization of the three as-prepared films under 5 h of light exposure confirms the excellent photocatalytic activity of CN/PVDF-HP, which shows a photo-decolorization rate of 76.77%, possibly owing to the presence of the photocatalyst on the PVDF surface. Moreover, CN/PVDF-HP retains 91% of its initial AR1-decolorization rate after two consecutive photo-decolorization cycles, confirming excellent stability during AR1-decolorization testing. All the CN/PVDF films exhibit moderate recyclability and stability on decomposition cycling. Therefore, the three as-prepared photocatalyst-loaded films show comparable performance and recyclability, exhibiting high potential for continuous water purification. The results of this study could guide future research on the development of high-performance wastewater treatment technologies.