Stable photodegradation of antibiotics by the functionalized 3D-Bi2MoO6@MoO3/PU composite sponge: High efficiency pathways, optical properties and Z-scheme heterojunction mechanism

Abstract

The designation and fabrication of heterogeneous photocatalyst with superior redox capability is an important technique for emerging pollutants treatment. In this study, we designed the Z-scheme heterojunction of stable 3D-Bi2MoO6@MoO3/PU, which could not only accelerate the migration and separation in photogenerated carriers, but also stabilize the separation rate of photo-generation carriers. In the Bi2MoO6@MoO3/PU photocatalytic system, 88.89% of oxytetracycline (OTC, 10 mg L−1) and 78.25%–84.59% of multiple antibiotics (SDZ, NOR, AMX and CFX, 10 mg L−1) could be decomposed within 20 min under the optimized reaction condition, revealing the superior performance and potential application value. Specifically, the morphology, chemical structure and optical properties detection of Bi2MoO6@MoO3/PU greatly affected the direct Z-scheme electron transferring mode in the p-n type heterojunction. Besides, the ·OH, h+, ·O2− dominated the photoactivation process through ring-opening, dihydroxylation, deamination, decarbonization and demethylation in OTC decomposition. Expectantly, the stability and universality of Bi2MoO6@MoO3/PU composite photocatalyst would further broaden the practical application and demonstrated that the potential of photocatalytic technique in antibiotics pollutants for wastewater remediation.