Interfacial Electric Field Tuning Carbon-Catalyzed Persulfate Activation toward a Maneuverable Oxidation Pathway for Enhanced Removal of Bisphenol A

Carbocatalyst/persulfate is a green, highly oxidativesystem fordecontaminating refractory aqueous organic pollutants. Exploring facileroutes to tune the catalytic activity and selectivity (persulfateactivation pathway) of carbonaceous materials toward persulfate activationis very appealing, which offers a platform for selective oxidationof organic pollutants. In this work, we showed that the interfacialelectric field (IEF) is a facile approach to alter the catalytic activityand selectivity of carbon/persulfate systems via the field-dipoleeffect. To study the IEF effects, a carbon electrode fabricated frompowdery carbons was assembled into an asymmetric quasi-capacitivedeionization cell, and positive/negative voltages were applied. Throughintegrated experimental and theoretical investigations, we found thatthe bond structures of both persulfate anion and its transition statewere changed under IEF, while the scenarios in the cases of positiveand negative IEF were distinct. Positive IEF induces/reinforces thenonradical oxidation pathway based on carbon-persulfate complexesin the carbon/persulfate system, while different persulfate activationpathways (nonradical carbon-persulfate complexes and/or free radicals)can be induced under negative IEF depending on the bonding strengthbetween persulfate and the carbocatalyst. Our results offer a feasibleapproach to tune the redox potentials of carbon-based advanced oxidationsystems toward selective oxidation of organic pollutants. This work extended the application ofinterfacial electricfield in persulfate-based advanced oxidation processes.