Resorcinol-formaldehyde resins/MIL-88A(Fe) S-scheme heterojunctions drive photo-self-Fenton system for enhanced tetracycline degradation and bacterial inactivation: Mechanism insight and DFT calculation

Abstract

Herein, a photo-self-Fenton system of resorcinol-formaldehyde resins/MIL-88A(Fe) (RF/88A) S-scheme heterojunction was successfully established to in-situ generate and activate H2O2 toward tetracycline (TC) degradation and sterilization under visible light illumination. As a result, the 35 %-RF/88A (the mass ratio of RF to 88A was 35 %) can remove most TC and kill approximately 100 % E. coli and S. aureus. Notably, the composites presented superior repeatability and wide pH application range. Fukui index identified the reaction sites of TC molecule and quantitative structure-activity relationship (QSAR) forecasted intermediates toxicity. Density functional theory (DFT) calculations were performed to investigate electron transfer mechanism of the heterojunctions on a molecular scale. Such a S-scheme charge transfer route was also proved by in situ irradiated X-ray photoelectron and electron paramagnetic resonance measurements. In summary, this research innovatively provides deep insights into the in-situ generation and activation of H2O2 and exhibited an environmentally friendly way toward pollutant degradation and sterilization.