Photocatalysis was combined with O3 (O3-PCO) for better destruction performance of formaldehyde and toluene. It is of significance to study the stability of O3-PCO process since it is essential to the application of O3-PCO technology. The present work investigated the mechanism of enhanced performance and improved stability in the O3-PCO process under different operating conditions (e.g., humidity and initial O3 concentration). Results indicated that O3 improved remarkably the removal efficiency of formaldehyde and toluene with increased photocatalyst durability. The O3-PCO process exhibited excellent stability during the variation of humidity and initial O3 concentration. O3-PCO process has enhanced performance because it comprises more sub-processes (e.g., UV/O3 and O3/TiO2) for destroying pollutants than the PCO process alone does.
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