Role of in-situ electro-generated H2O2•••bridge in tetracycline degradation governed by mechanochemical Si-O anchoring Cu2+ as electron shuttle during E-peroxone process

The efficient mineralization of tetracycline (TC) and reaction mechanism were investigated by designing heterogeneous H2O2 center dot center dot center dot bridge linked with active sites in higher valency species. CuSi-BM60 was synthesized by anchoring Cu2+ on Si-O functional groups of MCM-48 by mechanochemical technology to assist electro-peroxone treatment (E-peroxone). Results suggested that catalysts as electron shuttle enhanced electron transfer and reactive oxygen species (ROSs) generation, showing a complete tetracycline (TC) degradation and excellent mineralization (73.2%, 60 min). Cu sites significantly raised the interaction with in-situ electro-generated H2O2, generating uneven electron cloud distribution by Si-O center dot center dot center dot Cu center dot center dot center dot HO-OH* bonding bridge, which enlarged H-O bonding length/angle near Cu and decreased orbital energy level gap. This work provided new insights into the complex of ball milling mediated Cu2+ with H2O2 accompanied by the cycle of H-O bonding cleavage and regeneration for efficient ROSs production during E-peroxone.

Automated summary

The efficient mineralization and reaction mechanism of tetracycline (TC) were investigated using a heterogeneous H2O2⋯ bridge linked with active sites. The results showed that the catalysts enhanced electron transfer and reactive oxygen species (ROSs) generation, leading to complete degradation and excellent mineralization of TC. The interaction between Cu sites and in-situ electro-generated H2O2 promoted ROSs production through the bonding bridge, providing new insights into efficient ROSs production during the process.