Enhanced synergistic performance of g-C3N4/MoS2 with hollow structure for tetracycline photocatalytic degradation in complex environments: Performance and mechanism

The toxicity of antibiotic and heavy metal combined pollutants is greater than single antibiotic, achieving its synergistic removal is the key. In this work, a novel g-C3N4/MoS2 photocatalyst with hollow structure (CN/MS-V-3) was fabricated by one-step solvothermal method. As expected, CN/MS-V-3 showed an outstanding removal efficiency for tetracycline and Cu2+ of 98.49% and 99.90%, respectively. The excellent photocatalytic degradation performance for tetracycline in compound wastewater mainly ascribed to the enhanced visible-light capture ability by hollow structure of CN/MS-V-3, formation 1O2 and ·OH, and the cycle of Cu2+/Cu+ and Mo2+/Mo4+ induced the fast electrons transport. The contamination of Cu2+ in wastewater can play as an accelerator in the CN/MS-V-3 reaction system to improve the degradation performance of tetracycline. DFT results indicated that CN/MS-V-3 heterojunction was formed by combination of side surface MoS2–V and g-C3N4, and the Cu adsorption onto CN/MS-V-3 showed a potential formation of Cu–N and Cu–S bonds. In addition, the tetracycline degradation pathways and evaluation of toxicity of intermediates were also proposed. This work not only provides a promising technology for antibiotic and heavy metal combined contamination removal, but also a clever use of Cu variable valence to accelerate electron cycling to improve the removal performance of the CN/MS-V-3.