Despite extensive studies, the fundamental understanding of synergistic mechanisms between sonolysis and photocatalysis for the abatement of persistent organic pollutants (POPs) remains uncertain. As different phases formed under ultrasound irradiation, hydrophilic POPs, sulfamethoxazole (SMX, Kow: 0.89), predominantly resides in bulk liquid and is ineffectively degraded by sonolysis (kUS = 3.33 × 10−3 min−1) since <10% of hydroxyl radicals (·OH) formed at the gas-liquid interface of cavitation is diffused into the bulk, whereas the other fraction rapidly recombines into hydrogen peroxide (H2O2). This study provides a proof-of-concept for the mechanism by presenting various analytical results, endorsing the synergistic role of photoexcited electrons in splitting sonolysis-induced H2O2 into ·OH, particularly in the bulk phase. In a sonophotocatalytic system, the hydrophobic POPs such as bisphenol A (BPA) and atrazine (ATZ) were mainly degraded in gas-liquid interface indicated by the low synergistic values correlation compared to SMX [i.e., SMX has a higher synergistic factor, fsyn (3.26) than BPA (1.30) and ATZ (1.35)]. Also, fsyn was found linearly correlated with the contribution factor of photocatalysis to split H2O2. Three times of consecutive kinetics using an effluent of municipal (MP) wastewater spiked by POPs presented >98% POPs and >96% total organic carbon (TOC) removal.
|Journal||Journal of Hazardous Materials|
|Publication status||Published - 2021 Aug 15|
Bibliographical noteFunding Information:
The present research has been conducted by the Research Grant of Kwangwoon University in 2021, National Research Foundation , the Republic of Korea (No. 2020R1F1A1075839 ), and Korea Environment Industry & Technology Institute (Grant 2020002470002 ).
© 2021 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Health, Toxicology and Mutagenesis