Bypassing gas-liquid mass transfer resistance in a Fenton wet scrubber for boosting the removal of hydrophobic styrene: Construction of a novel gas-solid-liquid triple-phase interface

Abstract

Advanced oxidation processes (AOPs, such as Fenton) coupled with wet scrubbers are powerful and eco–friendly for VOCs treatment. However, challenges remain in the efficient removal of hydrophobic VOCs due to the extremely high gas-liquid mass transfer resistance. Herein, we constructed a “gas-solid-liquid triple-phase interface” in a Fenton wet scrubber via fabricating a new amphiphilic catalyst (PAN@Fe₃O₄@Nafion), which allows to capture gas bubbles and directly convey the VOCs to catalytic active center through gas transport and bypass the gas-liquid mass transfer (rate–determining) step. Compared with system with the unmodulated catalyst, the removal efficiency of hydrophobic styrene in the triple-phase interface Fenton wet scrubber was improved by 69.0%, the intermediates were dominated by small–molecule fatty acids (98.0%), and the outlet CO₂ concentration and H₂O₂ consumption increased by 22.1% and 19.6%, respectively. Notably, mechanism analysis via confocal laser scanning microscopy and contact angle measurements revealed the arrangement of hydrophilic and hydrophobic regions on the catalyst surface. Moreover, the affinity ability of bubbles was 2.5 times greater and the mass transfer enhancement factor reached 2.2 in the triple-phase interface Fenton wet scrubber system. This study provides a new avenue for overcoming the gas-liquid mass transfer resistance of hydrophobic VOCs in AOP wet scrubbers.