UV-Electrochemical Catalytic Oxidation of Quinoline-Containing Wastewater Using an IrO2-Based Anode: COD Reduction, Degradation Kinetics, and Transformation Pathway
- 1China Geological Survey , , ,
- 2China University of Mining & Technology (Beijing) , , ,
- 3Hunan Xiangtan Hydrology and Water Resources Survey Center , No. 128, Ji’an Road , Baota Subdistrict, Yuetang District, , ,
Abstract
Quinoline is a refractory nitrogen-containing pollutant commonly found in coal chemical, coking, pharmaceutical, and dye wastewater. Although advanced oxidation processes have shown potential for quinoline removal, an integrated understanding of pollutant removal, COD reduction, degradation kinetics, and intermediate transformation in UV-electrochemical systems remains limited. In this study, simulated quinoline-containing wastewater was treated using a dual-wavelength UV-electrochemical catalytic oxidation system equipped with a commercial Ti/IrO2 anode and a stainless-steel cathode. The effects of current density, electrolysis time, NaCl concentration, and initial pH on quinoline degradation were systematically investigated, while COD reduction, degradation kinetics, and intermediate transformation were further evaluated by HPLC and GC-MS. Under a current density of 30 mA/cm2, NaCl concentration of 0.5 mol/L, near-neutral initial pH, and reaction time of 90 min, quinoline and COD removal efficiencies reached 87.2% and 84.7%, respectively. Further increases in current density or reaction time produced only limited additional improvement under the investigated conditions. Control experiments showed higher quinoline removal in the combined process than in either individual process. Kinetic analysis showed that quinoline degradation could be adequately described by an apparent pseudo-first-order model. HPLC and GC-MS analyses indicated a proposed transformation pathway involving hydroxylation and quinolinone formation, followed by cleavage of the aromatic and heterocyclic structures and subsequent oxidation to small-molecule organic acids. These results provide an integrated evaluation of quinoline removal, COD reduction, kinetic behavior, and intermediate transformation, thereby providing a basis for further optimization of UV-electrochemical treatment of quinoline-containing wastewater.
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BibTeX
@article{ning2026uvelectrochemical,
title = {{UV-Electrochemical Catalytic Oxidation of Quinoline-Containing Wastewater Using an IrO2-Based Anode: COD Reduction, Degradation Kinetics, and Transformation Pathway}},
author = {Kejia Ning and Han Yang and Xin Sun and Shan Li and Jiulong Cui and Lin Ma and Yanyan Deng and Xiaoke Li and Gen Huang and Zechao Huangfu and Pengfei Zhao and Qiming Zhuo},
journal = {ACS Omega},
year = {2026},
month = nov,
doi = {10.1021/acsomega.6c08661},
url = {https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c08661/5466248/UV-Electrochemical-Catalytic-Oxidation-of},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - UV-Electrochemical Catalytic Oxidation of Quinoline-Containing Wastewater Using an IrO2-Based Anode: COD Reduction, Degradation Kinetics, and Transformation Pathway
AU - Kejia Ning
AU - Han Yang
AU - Xin Sun
AU - Shan Li
AU - Jiulong Cui
AU - Lin Ma
AU - Yanyan Deng
AU - Xiaoke Li
AU - Gen Huang
AU - Zechao Huangfu
AU - Pengfei Zhao
AU - Qiming Zhuo
PY - 2026
DA - 2026/11/07
JO - ACS Omega
DO - 10.1021/acsomega.6c08661
UR - https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c08661/5466248/UV-Electrochemical-Catalytic-Oxidation-of
AB - Quinoline is a refractory nitrogen-containing pollutant commonly found in coal chemical, coking, pharmaceutical, and dye wastewater. Although advanced oxidation processes have shown potential for quinoline removal, an integrated understanding of pollutant removal, COD reduction, degradation kinetics, and intermediate transformation in UV-electrochemical systems remains limited. In this study, simulated quinoline-containing wastewater was treated using a dual-wavelength UV-electrochemical catalytic oxidation system equipped with a commercial Ti/IrO2 anode and a stainless-steel cathode. The effects of current density, electrolysis time, NaCl concentration, and initial pH on quinoline degradation were systematically investigated, while COD reduction, degradation kinetics, and intermediate transformation were further evaluated by HPLC and GC-MS. Under a current density of 30 mA/cm2, NaCl concentration of 0.5 mol/L, near-neutral initial pH, and reaction time of 90 min, quinoline and COD removal efficiencies reached 87.2% and 84.7%, respectively. Further increases in current density or reaction time produced only limited additional improvement under the investigated conditions. Control experiments showed higher quinoline removal in the combined process than in either individual process. Kinetic analysis showed that quinoline degradation could be adequately described by an apparent pseudo-first-order model. HPLC and GC-MS analyses indicated a proposed transformation pathway involving hydroxylation and quinolinone formation, followed by cleavage of the aromatic and heterocyclic structures and subsequent oxidation to small-molecule organic acids. These results provide an integrated evaluation of quinoline removal, COD reduction, kinetic behavior, and intermediate transformation, thereby providing a basis for further optimization of UV-electrochemical treatment of quinoline-containing wastewater.
SN - 2470-1343
ER -