Association of surface dielectric barrier discharge and photocatalysis in continuous reactor at pilot scale: Butyraldehyde oxidation, by-products identification and ozone valorization

• Butyraldehyde removal by plasma and photocatalysis is studied at pilot scale.
• Effects of some operating parameters on performance of each process were tested.
• A synergetic effect is confirmed by plasma and photocatalysis combined.
• Sequential and continuous configurations of TiO2/MnO2 with plasma were tested.
• Intermediates by-products of butyraldehyde has been identified.

Coupling nonthermal plasma with other processes has been studied over the past few years and promising results were obtained concerning VOCs removal for atmospheric pollution control. In this work, butyraldehyde (BUTY) removal by a dielectric barrier discharge (DBD) plasma coupled with different (photo) catalysts based on TiO2 and MnO2 was studied. DBD plasma system and an immobilized TiO2 and MnO2 at different percentages are continually and sequentially combined in order to decompose residual ozone. Indeed, different ways of combination are listed. Effects of relative humidity and initial BUTY concentration on its conversion rate and the distribution of byproducts were examined and discussed. Results with pilot scale showed that combination of plasma and photocatalysis led to an enhancement of BUTY abatement compared to the separate systems. When 100% of MnO2 catalyst was placed in the post discharge zone, the performance of sequential DBD/MnO2 combined system is improved in terms of decomposition and conversion rate of the pollutant. In the same way, CO was reduced and CO2 selectivity was significantly improved when compared to the DBD plasma alone. Intermediate byproducts were identified and BUTY removal pathways are suggested.

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