A Novel Z-type 0D/2D BiOCl/NiAl-LDH heterojunction for photodegradation of multiple antibiotics in industrial wastewater: Degradation pathways and toxicity analysis

Abstract

In this paper, two metal compounds were combined and successfully prepared a Z-type BiOCl/NiAl-LDH(B/NL) heterojunction for the degradation of various antibiotics in industrial wastewater under visible light. The optical properties and photocatalytic activity of B/NL can be adjusted by varying the amount of NiAl-LDH. In the simulated degradation of tetracycline (TC) under visible light, B/NL-11 showed the best photodegradation efficiency, with a degradation rate of 92.57 % within 100 min. By using catalytic materials to degrade industrial wastewater, the degradation rate of tetracycline antibiotics (tetracycline, oxytetracycline) is more than 70 %, and the degradation rate of quinolone antibiotics (ciprofloxacin, norfloxacin) is more than 50 %. Mineralization process of the B/NL-11 system to degrade antibiotics in industrial wastewater was evaluated by 3D EMMS technology, and the degradation pathways were analyzed by LC-MS. The toxicity of the intermediate products produced is much lower than that of the pollutants themselves, and there is no secondary pollution. The degradation activity of BiOCl/NiAl-LDH is due to the construction of heterojunction adds many active sites, and the formed band structure promotes the efficient separation and transfer of photogenerated electron-holes. The free radical trapping experiment proved that h+, ∙O2−, ∙OH was the main active substance in the degradation process, and finally proposed the Z-type heterojunction mechanism.