Probe on the pivotal role of green rust in improving the enzymatic activity and facilitating the formation of O in Fenton-like process for degradation of 4-chlorophenol.

Iron-based materials have demonstrated significant efficacy in catalyzing hydrogen peroxide (HO) for the removal of antibiotics from aquatic environments. Green rust (GR), a hybrid valence state iron-based catalyst, was synthesized. By exploiting the catalytic properties of glucose oxidase (GOx) to generate HO from glucose (Glu), a GR-GOx/Glu system for the removal of recalcitrant organic compound 4-chlorophenol (4-CP) was constructed. In terms of pollutant degradation efficiency, an increase of 30% was observed compared to Fe/HO system. Utilizing density functional theory (DFT), we calculated the electrostatic potential energy and charge density distribution, demonstrating the existence of active electron transfer between GR and flavin adenine dinucleotide (FAD), which subsequently enhanced the activity of GOx. The enhancement was pivotal for the sustained generation of preferred oxidative species and rapid degradation of pollutants within the system. Furthermore, the acids and HO generated during enzyme catalysis not only neutralized the alkalinity released by the Fenton-like reaction but also promoted the conversion of superoxide radical (·O) to singlet oxygen (O). Overall, this study elucidates the fundamental motivation underlying the enhancement of enzymatic activity and highlights the critical role of O within the system, providing valuable insights into the potential mechanisms by which metal hydroxides catalyze the HO process.