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

Abstract

Heavy metal complexes exhibit strong toxicities to aquatic ecosystems, and quite resistant to traditional treatments. 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 transmission 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+, ·O2–, ·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.