Metal-free graphitic carbon nitride/black phosphorus quantum dots heterojunction photocatalyst for the removal of ARGs contamination

Antibiotic resistant bacteria (ARB) and genes (ARGs) have become hot topics in the field of water purification. In this paper, graphite carbon nitride (g-C₃N₄) and black phosphorus quantum dots (BPQDs) were used as raw materials to fabricate a non-metallic heterojunction composite photocatalyst (H-g-C₃N₄/BPQDs) by hydrothermal impregnation, high-temperature calcination, and ice-assisted ultrasound. The H-g-C₃N₄/BPQDs was used to remove antibiotics and biological pollution from water under visible light irradiation. Based on the porous structure and high specific surface area of H-g-C₃N₄, the the obtained type II heterojunction structure promoted the absorption of visible light, accelerated the interfacial charge transfer, and inhibited the recombination of photogenerated electron-hole pairs. Under visible light irradiation, the degrading efficiency of TC by H-g-C₃N₄ /BPQDs exceeded 91% in 30 min, and E. coli K12 M1655 can be completely inactivated in 4 h. In addition, the maximum inactivation rate of H-g-C₃N₄ /BPQDs for E. coli HB101(RP4) was 99.99% in 4 h, and the degradation efficiency of RP4 was more than 85%. This study provides not only a new idea for the design of green g-C₃N₄-based non-metallic heterojunction photocatalysts but also a broad prospect for the application of g-C₃N₄-based photocatalysts for the removal of ARGs in water treatment.