Plasma-microbubble treatment and sustainable agriculture application of diclofenac-contaminated wastewater

Qi Liu; Wenchong Ouyang; Xusheng Yang; Yuanyuan He; Zhengwei Wu; Kostya Ken Ostrikov

doi:10.1016/j.chemosphere.2023.138998

Plasma-microbubble treatment and sustainable agriculture application of diclofenac-contaminated wastewater

Chemosphere. 2023 Sep:334:138998. doi: 10.1016/j.chemosphere.2023.138998. Epub 2023 May 19.

Authors

Qi Liu¹, Wenchong Ouyang¹, Xusheng Yang², Yuanyuan He¹, Zhengwei Wu³, Kostya Ken Ostrikov⁴

Affiliations

¹ School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, People's Republic of China.
² Center for Advancing Electronics Dresden (CFAED) and Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
³ School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, People's Republic of China; Institute of Advanced Technology, University of Science and Technology of China, Hefei, People's Republic of China; CAS Key Laboratory of Geospace Environment, University of Science and Technology of China, Hefei, People's Republic of China. Electronic address: wuzw@ustc.edu.cn.
⁴ School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, Queensland, 4000, Australia; Centre for Materials Science, Centre for Clean Energy Technologies and Practices, and Centre for Waste Free World, Queensland University of Technology (QUT), Brisbane, Queensland, 4000, Australia.

PMID: 37211167
DOI: 10.1016/j.chemosphere.2023.138998

Abstract

The demand for efficient wastewater treatment is becoming increasingly urgent due to the rising threat of pharmaceutical residues in water. As a sustainable advanced oxidation process, cold plasma technology is a promising approach for water treatment. However, the adoption of the technology encounters several challenges, including the low treatment efficiency and the potentially unknown environmental impact. Here, microbubble generation was integrated with cold plasma system to enhance treatment of wastewater contaminated with diclofenac (DCF). The degradation efficiency depended on the discharge voltage, gas flow, initial concentration, and pH value. The best degradation efficiency was 90.9% after 45 min plasma-bubble treatment under the optimum process parameters. The hybrid plasma-bubble system exhibited strongly synergistic performance heralded by up to seven-times higher DCF removal rates than the two systems operated separately. The plasma-bubble treatment remains effective even after addition of SO₄^2-, Cl^-, CO₃^2-, HCO₃^-, and humic acid (HA) as interfering background substances. The contributions of •O₂^-, O₃, •OH, and H₂O₂ reactive species to the DCF degradation process were specified. The synergistic mechanisms for DCF degradation were deduced through the analysis of the degradation intermediates. Further, the plasma-bubble treated water was proven safe and effective to stimulate seed germination and plant growth for sustainable agriculture applications. Overall, these findings provide new insights and a feasible approach with a highly synergistic removal effect for the plasma-enhanced microbubble wastewater treatment, without generating secondary contaminants.

Keywords: Cold plasma; Diclofenac degradation; Microbubbles; Synergistic effect; Wastewater Treatment.

MeSH terms

Agriculture
Diclofenac / chemistry
Hydrogen Peroxide / chemistry
Microbubbles
Plasma Gases* / analysis
Wastewater
Water Pollutants, Chemical* / analysis

Substances

Wastewater
Diclofenac
Hydrogen Peroxide
Plasma Gases
Water Pollutants, Chemical