Optimizing the atrazine degradation in g-C₃N₄@BiOBr/polyvinylidene fluoride photocatalytic membrane system

In this study, g-C₃N₄@BiOBr heterostructure was synthesized at different molar ratios and dispersed into a polyvinylidene fluoride (PVDF) matrix for the photodegradation of atrazine (ATZ, herbicide) under visible light. The investigation of the photocatalytic performance of g-C₃N₄@BiOBr/PVDF membrane under different operating parameters has not been extensively studied in the literature. Thus, this study focused on the optimization of the g-C₃N₄@BiOBr/PVDF membrane degradation system and deep exploration of the degradation mechanism. Various analyses characterized the as-prepared catalysts and membranes, including XRD, TEM, FTIR, EDX, SEM, XPS, and DRS. The g-C₃N₄@BiOBr/PVDF membrane (g-C₃N₄@BiOBr at a mole ratio 1:3) showed the highest photocatalytic activity for ATZ removal among the composite membranes. The response surface methodology (RSM) was used to optimize the operating parameters, exhibiting that pH 3, initial ATZ concentration of 0.5 mg/L, and BiOBr mole ratio of 0.75 were the optimum conditions. The contribution of reactive species to the degradation mechanism was investigated using efficient scavengers, confirming the significant roles of •O₂^- and h⁺ in the reaction process. Furthermore, the as-prepared membrane demonstrated enhanced reusability and stability with an 81 % ATZ removal rate after five cycles. The generated intermediates were identified using liquid chromatography-mass spectroscopy analysis indicating the degradation of ATZ to simpler compounds. The mechanism of the photocatalytic degradation of atrazine by g-C₃N₄@BiOBr/PVDF was further proposed. This study proposes a low-cost, efficient, and stable photocatalytic membrane system that can be executed in real applications.