Visible-NIR responsive Ag2O couple with MIL-53(Fe) on CS as S-scheme photocatalyst for efficient simultaneous removal of Cr(VI) and norfloxacin.

[Display omitted] • S-type heterojunctions of MIL-53(Fe)/Ag 2 O on charcoal sponge (CS) was realized. • The combination of photocatalysis and Fenton effectively improve the removal efficiency of compound pollutants. • Inhibition zone tests demonstrated that the toxicity of NFX intermediates to E. coli gradually decreased as the degradation of NFX progressed. • CS/MIL-53(Fe)/Ag 2 O exhibits improved separation efficiency of photoinduced carriers and REDOX capacity. • DFT calculations were used to probe the electronic structures and reaction mechanism. This study addresses the urgent need to develop easily recoverable and efficient photocatalysts for the treatment of compound polluted wastewater. Herein, S-scheme MIL-53(Fe)/Ag 2 O heterojunctions on a charcoal sponge (CS) were constructed by solvothermal-chemical precipitation method, exhibiting high separation efficiency of photoinduced carriers and reduction–oxidation (REDOX) capacity. The synthesized CS/MIL-53(Fe)/Ag 2 O was characterized by SEM, TEM, XRD, and XPS, confirming the successful deposition and uniform distribution of MIL-53(Fe) and Ag 2 O nanoparticles on CS. Moreover, CS/MIL-53(Fe)/Ag 2 O exhibits an extensive light absorption range from visible to near-infrared (NIR) light, thereby significantly enhancing its photocatalytic activity. In present of H 2 O 2 , CS/MIL-53(Fe)/Ag 2 O demonstrated outstanding removal efficacy of norfloxacin (NFX, 96 %, pH=7) or Cr(VI) (100 %, pH=3) through the photocatalytic-Fenton reaction, which was notably superior to that of CS/MIL-53(Fe) (50.4 % NFX, 56.8 % Cr(VI)) and CS/Ag 2 O (44.3 % NFX, 38 % Cr(VI)). Importantly, when CS/MIL-53(Fe)/Ag 2 O was used to treat combined polluted wastewater containing both Cr(VI) and NFX, the removal efficiency of Cr(VI) and NFX showed a significant synergistic effect. Additionally, inhibition zone tests demonstrated that the toxicity of NFX intermediates to E. coli gradually decreased as the degradation of NFX progressed. Furthermore, density functional theory (DFT) calculation and relevant characterization were conducted to elucidate the reaction mechanism of S-scheme heterojunctions, highlighting the enhanced separation rate of photo-induced carriers and REDOX capability. This work not only offers a promising approach for construction of MOF-based S-scheme semiconductor heterojunctions, but also presents promising prospects for the purification of compound polluted wastewater containing norfloxacin and Cr(VI). [ABSTRACT FROM AUTHOR]