Efficient degradation of aflatoxin B1 and ochratoxin A using dual Z-scheme Sr2MgSi2O7: Eu2+, Dy3+/BiVO4/NH2-UiO-66 heterojunctions with round-the-clock photocatalytic activity

Developing a green and efficient technology for decomposing aflatoxin B 1 (AFB 1 ) and ochratoxin A (OTA) in grains has important theoretical value and application prospects for ensuring food safety. A dual Z-scheme ternary heterojunction photocatalyst, Sr 2 MgSi 2 O 7 :Eu 2+ ,Dy 3+ /BiVO 4 /NH 2 -UiO-66 (SBN), was prepared via a self-assembling hydrothermal approach. The SBN heterojunction photocatalyst exhibits round-the-clock photocatalytic activity due to the intrinsic light source of Sr 2 MgSi 2 O 7 : Eu 2+ , Dy 3+ (SMS). Dual Z-scheme mechanism was proposed and validated through detailed analysis of quenching experiments, ESR spectra, band arrangement, and charge transfer processes. The dual Z-scheme mechanism not only promotes the effective transfer and separation of photo generated charge carriers during charge carrier transport, but also maintains significant reduction and oxidation potentials. SBN photocatalyst exhibits stable and persistent photocatalytic performance, significantly enhancing the degradation efficiency of AFB 1 and OTA under all-weather conditions. Experimental data shows that the removal rate of AFB 1 increased from 69.60 % after 60 min of illumination to 83.9 % after 4 h of turning off the light source; At the same time, the removal rate of OTA increased from 64.8 % to 78.1 %. •O 2 − and •OH were identified as key active species in photocatalytic reactions. Based on the analysis of AFB 1 and OTA degradation intermediates and the prediction of degradation sites using density functional theory (DFT), degradation pathways for AFB 1 and OTA were proposed. Collectively, these findings suggest a highly promising practical approach for the detoxification of mycotoxins in grain commodities.