Enhanced Removal of Bpa in Water: A Redistribution of the Decisive Position of Active Species Due to the Interfacial Electric Field in Fe2o3/Tio2 Heterojunction

Abstract

Ineffective utilization of generated oxidants, such as H2O2, together with the nonselectivity of ⚫OH, the principal active species, has significantly hindered the growth of discharge plasma in application for wastewater treatment. Herein, the introduction of constructed Fe2O3/TiO2 heterojunction to dielectric barrier discharge plasma (DBDP) not only increased oxidant utilization, but also triggered a shift of decisive position of active species from ⚫OH to selective 1O2 and O2⚫- towards bisphenol A (BPA) degradation. Experiments and theoretical calculations collectively revealed that the above process was realized under the joint drive of high-energy electrons, photons, and an interfacial electric field in Fe2O3/TiO2 heterojunction. Among them, the interfacial electric field facilitated the separation of electron-hole (e--h+) pairs and the transfer of charge to the antibonding orbit for O-O in H2O2, dissolved O2 and O3 absorbed on the metal sites. Such a work offered theoretical guidance for the ongoing growth of discharge plasma at both the macro and micro levels.

Keywords: Fe2O3/TiO2 heterojunction, DBDP, 1O2, O2⚫-