Dynamic coordination of two-phase reactions in heterogeneous Fenton for selective removal of water pollutants

Abstract

The •OH-mediated heterogeneous Fenton reaction has been widely applied despite the limitations of low pollutant selectivity and unclear oxidation mechanism. Here we reported an adsorption-assisted heterogeneous Fenton process for the selective degradation of pollutants and systematically illustrated its dynamic coordination in two phases. The results showed that the selective removal was improved by (i) surface enrichment of target pollutants via electrostatic interactions including real adsorption and adsorption-assisted degradation and (ii) inducing the diffusion of H2O2 and pollutants from the bulk solution to the catalyst surface to trigger the homogeneous and surface heterogeneous Fenton reactions. Furthermore, surface adsorption was confirmed as a crucial but not necessary step for degradation. Mechanism studies demonstrated that •O2– and Fe3+/Fe2+ cycle increased •OH generation, which remained active in two phases within ⁓244 nm. These findings are critical for understanding the removal behavior of complex targets and expanding heterogeneous Fenton applications.