Ozone (O3) demulsification shows great potential in emulsion wastewater treatment due to its strong oxidative properties. However, the low mass transfer efficiency and oxidation selectivity of O3 cannot be ignored. Herein, a MnO2/porous spontaneously polarized ceramic (MnO2/PSPC) composite with strong interfacial interactions and self-powered electric field was prepared for heterogeneous catalytic ozonation (HCO) to achieve efficient demulsification. Excellent remanent polarization (0.00858 μC/cm2) together with systematic electrochemical characterizations of MnO2/PSPC demonstrated its significant charge transfer capability, which is essential for the subsequent reduction of Mn4+ in the HCO demulsification process. O3- MnO2/PSPC exhibited excellent demulsification performance with 99 % demulsification rate of cetyltrimethylammonium bromide-stabilized emulsion within 30 min, outperforming O3 (130 min), O3-MnO2 (60 min), and O3-PSPC (90 min). O3-MnO2/PSPC showed effective demulsification of non-/anionic surfactant stabilized emulsions and excellent stability after 5 cycles. Density functional theory calculations together with characterizations illustrate that potential difference-induced rapid electron transfer and water flow-induced self-powered electric field were the fundamental motivation for the fast Mn3+/Mn4+ cycle and O3 adsorption/decomposition to generate reactive oxygen species (ROS). Notably, the oxidation of surfactants by ROS led to the coalescence of the oil droplets. This study provides an efficient, sustainable, and energy-efficient method to improve the O3 demulsification performance.
Keywords: Demulsification; Heterogeneous catalytic ozonation; MnO(2); Self-powered electric field; Strong interfacial interactions.
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