Forming derivative solid radicals on pyrolytic carbon via persistent free radicals coordinating heavy metals: Peroxide-free degradation of organic pollutants

Abstract

The solid-state persistent free radicals (PFRs) on pyrolytic carbons are attracting increasing attentions as they can directly degrade pollutants in water, while the redox behaviors and pathways over the PFRs during remediating coexisting aqueous pollutants have never been clarified. Herein, we discovered that the PFRs-induced remediation was an integrated process, where the original PFRs on the model pyrolytic carbon (TLRB) would first deliver electrons to the exterior heavy metals (HMs) forming derivative solid radicals (DSRs). The DSRs then acted as an electroactive bridge to further attract, stabilize, and degrade the surface-bound organic pollutants (OCs), eventually achieving a highly efficient removal of coexisting HMs and OCs. It is appealing to find that the HMs can trigger the in-situ upgrading of original PFRs to the DSRs by acting as an oxidant, rather than a pollutant. Such a peroxide-free regime alleviated the direct self-corrosion by radicals, thus promising a better effectiveness and recyclability of catalytic system.