Non-thermal plasma coupled liquid-phase catalysis /Fe2+ for VOCs removal: Enhanced mechanism of protocatechuic acid

Non-thermal plasma coupling Fe 2+ containing liquid-phase catalysis (NTP-LC/ Fe 2+ ) can effectively reuse the byproduct ozone (O 3 ) of NTP in LC/ Fe 2+ for volatile organic compounds (VOCs) degradation. However, the low recycling rate of Fe 2+ /Fe 3+ resulted in poor catalytic effect of the coupling system. In this study, the chelator protocatechuic acid (PCA) was added to LC/Fe 2+ to enhance the removal of representative VOC acetone. The results showed that adding PCA increased the acetone removal efficiency to 91% and kept O 3  ∼ 100% removed within 180 min. The mechanism of PCA-enhanced acetone degradation was that PCA accelerated the Fe 3+ /Fe 2+ cycle by generating PCA-Fe 3+ chelates, which prevented the Fe 3+ from precipitation and promoted the production of OH and O 2 - for acetone oxidation.