https://www.sciencedirect.com/science/article/abs/pii/S1385894721023998

Highlights

• •Catalytic ozonation exhibits high CB/DCE conversion over few MnO2 at 120 oC.

• •O3 significantly enhances Cl-VOCs adsorption and inhibits byproducts formation.

• •Catalytic ozonation maintains high conversion in long-term tests even with H2O.

• •Catalytic ozonation relates to acidity, oxygen vacancy and CO2 desorption of MnO2.

Abstract

This paper conducted catalytic ozonation and oxidation of chlorobenzene (CB) and dichloroethane (DCE) over three synthesized MnO2 catalysts with different properties. Catalytic ozonation exhibited high efficiency with less catalyst dosage at low temperature, ca. 30～120 oC, excellent stability, and less byproducts formation for both CB and DCE conversion. MnO2–I exhibited the best performance for all experiments, attributing to its abundant oxygen vacancies, more acid sites, and excellent CO2 desorption properties. Catalytic ozonation exhibited excellent stability with much fewer organic byproducts in effluent gas at 120 oC. H2O had no effect on catalytic ozonation but recovered catalytic oxidation performance. Besides, O3 existence attained high activity over deactivated catalyst by Cl poisoning. In–situ DRIFTs measurements validated facilitated transformation of intermediates during catalytic ozonation. These findings comprehensively verify the superiority of catalytic ozonation to attain highly stable and complete degradation of Cl–VOCs (chlorinated volatile organic compounds) at mild conditions.