For Simultaneous Oxidation of Antibiotics and Denitrification of Nitrate-Nitrogen in Water

- Published in the Chemical Engineering Journal (JCR IF 13.4, JCR Rank: Top 3.1%) -

 DBD Plasma Tandem Three-Electrode Fenton Process

Kwangwoon University's research team, comprising Dr. Geondeok Hwang (first author), Dr. Soyeon Yoon, Dr. Seokbeom Jang, Dr. Haslina Nu, Dr. Cho-eun Jong, and Professor Min Jang (corresponding author, Deputy Director of PBRC, and Director of JENTL) from the Department of Environmental Engineering, together with Professor Eunha Choi from the Plasma Bio Center, developed a DBD plasma tandem three-electrode Fenton process to simultaneously and effectively remove antibiotics and nitrate-nitrogen from water, and identified the mechanism of pollutant removal.

Ozone generated by dielectric barrier discharge (DBD) plasma has great potential for water treatment; however, its application is limited due to its low solubility and the resistance of certain pollutants to ozone. This study optimized and investigated the mechanisms of a tandem three-electrode Fenton (S-PEF) process combined with DBD plasma, designed to completely oxidize and decompose commonly detected antibiotics in water―sulfamethoxazole (SMX), amoxicillin (AMX), and norfloxacin (NOF)―under continuous water flow conditions. Additionally, it enables the denitrification and reduction of nitrate-nitrogen (NO₃-N), a challenging contaminant frequently found in groundwater, converting it to N₂.

The ozone-degradable antibiotics SMX and AMX are largely decomposed in the DBD plasma gas within the mixing chamber. Any residual SMX and AMX, along with NOF, which has high resistance to ozone, are fully eliminated by hydroxyl radicals generated from ozone in the anode chamber of the tandem three-electrode system. The continuous oxidation-reduction regeneration of specialized Fe in the tandem three-electrode system prevents the formation of secondary Fe sludge. Finally, in the cathode chamber containing copper oxide nanowires, NO₃-N and NO₂-N are denitrified to N₂ with a selectivity of over 95%. This sequential treatment process effectively mitigates the competitive effects of CO₃²？ and humic acid in wastewater through the oxidation action of hydroxyl radicals (·OH) generated from ozone. The S-PEF process completely decomposed all antibiotics across a wide range of water temperatures, outperforming standalone plasma treatment. Toxicity was significantly reduced according to Ecological Structure-Activity Relationship (ECOSAR) and E. coli sterilization toxicity assessments. Due to its high cost-effectiveness, the S-PEF water treatment process holds promising potential as an advanced technology for future wastewater and groundwater treatment.

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education and the Ministry of Science and ICT (Grant No. 2021R1A6A1A03038785). The findings were published in the October 20, 2024, online edition of the Chemical Engineering Journal (IF: 13.4, JCR rank: 3.1%) under the title “Sequential DBD Plasma-Assisted Tandem Tri-Electrode Fenton Process for Enhanced Antibiotics Treatment and Denitrification.”

 Web link : https://doi.org/10.1016/j.cej.2024.156930