The synergistic photocatalytic effects of surface-modified g-C3N4 in simple and complex pollution systems based on a macro-thermodynamic model

In this article, three types of surface-modified g-C3N4 (H+/g-C3N4, BCQDs/g-C3N4, and H+/BCQDs/g-C3N4) with unique photocatalytic properties have been successfully fabricated by simple and low-cost strategies. The morphology, elemental composition, textural properties, structural information, and photoelectric properties of the as-prepared materials are systematically characterized. Subsequently, the as-prepared materials are applied to Cr(VI) reduction, 4-FP degradation, and simultaneous Cr(VI) reduction with 4-FP degradation photocatalytic systems under normal and anoxic conditions. Based on the photocatalytic test results, we successfully constructed a macro-thermodynamic model to reveal the essential laws of synergistic photocatalytic effects. The constructed macro-thermodynamic model is suitable for complex photocatalytic systems and is of great significance for the application of photocatalytic technology in real wastewater treatment with multiple pollutants.