Effect of Natural Organic Matter on the Ozonation Mechanism of Trimethoprim in Water
Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Department of Environmental Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
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Water 2020, 12(10), 2935; https://doi.org/10.3390/w12102935
Received: 16 September 2020
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Revised: 13 October 2020
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Accepted: 16 October 2020
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Published: 21 October 2020
Trimethoprim (TMP) is often used for the treatment of various bacterial infections. It can be detected in water, and it is difficult to be biodegraded. In this study, the degradation mechanism of TMP through ozonation and the effect of humic acids (HA) were investigated. Excessive ozone (pH 6, 0 °C) could reduce the content of TMP to less than 1% in 30 s. However, when ozone (O3) was not excessive (pH 6, 20 °C), the removal efficiency of TMP increased with the increase of O3 concentration. Four possible degradation pathways of TMP in the process of ozonation were speculated: hydroxylation, demethylation, carbonylation, and cleavage. The presence of HA in water inhibit the generation of ozonation products of TMP. The excitation-emission matrices (EEM) analysis showed that with the extension of ozonation time, the fluorescence value in the solution decreased and the fluorescence peak blue shifted. These results indicated that the structure of HA changed in the reaction and was competitively degraded with TMP. According to the free radical quenching test, the products of pyrolysis, direct hydroxylation and demethylation were mainly produced by indirect oxidation.
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Keywords:
trimethoprim; ozonation; humic acids; direct oxidation; degradation pathways
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MDPI and ACS Style
Zhang, N.; Zhou, B.; Yuan, R.; Wang, F.; Chen, H. Effect of Natural Organic Matter on the Ozonation Mechanism of Trimethoprim in Water. Water 2020, 12, 2935. https://doi.org/10.3390/w12102935
AMA Style
Zhang N, Zhou B, Yuan R, Wang F, Chen H. Effect of Natural Organic Matter on the Ozonation Mechanism of Trimethoprim in Water. Water. 2020; 12(10):2935. https://doi.org/10.3390/w12102935
Chicago/Turabian StyleZhang, Ning, Beihai Zhou, Rongfang Yuan, Fei Wang, and Huilun Chen. 2020. "Effect of Natural Organic Matter on the Ozonation Mechanism of Trimethoprim in Water" Water 12, no. 10: 2935. https://doi.org/10.3390/w12102935
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