Highly efficient Cu-EDTA decomplexation by Ag/AgCl modified MIL-53(Fe) under Xe lamp: Z-scheme configuration

Heavy metal complexes exhibit strong toxicities to aquatic ecosystems, and quite resistant to traditional treat-ments. Bare MIL-53(Fe) could effectively decomplex Cu-EDTA under UV-light irradiation but not visible-light. How to realize its highly sunlight-driven decomplexation has attracted great attention. In this study, Ag-based modification strategy was selected, and Ag/AgCl nanoparticles were prepared synchronously to improve the sunlight-driven photocatalytic activity of MIL-53(Fe) for Cu-EDTA decomplexation. The Ag/AgCl modified MIL-53(Fe) (AM) heterojunction composites displayed greater photocatalytic decomplexation for Cu-EDTA than bare MIL-53(Fe). 93 % of Cu-EDTA elimination and nearly 60 % mineralization were achieved within 120 min simulated sunlight irradiation by the AM with Ag/Fe molar ratio of 1:2. The special Z-scheme configuration contributed to the significant improvement, in which metal Ag nanoparticles played the role of charge trans-mission in favor of promoting the generated electron-hole pair separation under UV-light irradiation, and surface plasmon resonance (SPR) effect was conducive to broadening its spectral response to visible-light region. Meanwhile, strong oxidizing species, including h+, center dot O2-, center dot OH, and 1O2, especially for h+, dominated the Cu-EDTA decomplexation, and some small organic acids and alcohols were the main products after 120 min irradiation.

Automated summary

Heavy metal complexes are highly toxic to aquatic ecosystems and resistant to traditional treatments. In this study, an Ag-based modification strategy was used to improve the sunlight-driven photocatalytic activity of MIL-53(Fe) for Cu-EDTA decomplexation. The modified AM heterojunction composites showed greater decomplexation efficiency, with 93% Cu-EDTA elimination and nearly 60% mineralization achieved within 120 minutes of simulated sunlight irradiation.