Sulfate radical-induced transformation of trimethoprim with CuFe2O4/MWCNTs as a heterogeneous catalyst of peroxymonosulfate: mechanisms and reaction pathways |
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| Authors: | Jing Kong Ruobai Li Fengliang Wang Ping Chen Haijin Liu Guoguang Liu Wenying Lv |
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| Affiliation: | School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 China, Fax: +86-20-3932-2548, +86-13533635690 ; School of Environment, Tsinghua University, Beijing 100084 China ; School of Environment, Henan Normal University, Henan Key Laboratory for Environmental Pollution Control, Xinxiang 453007 China |
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| Abstract: | Trimethoprim (TMP), a typical antibiotic pharmaceutical, has received extensive attention due to its potential biotoxicity. In this study, CuFe2O4, which was used to decorate MWCNTs via a sol–gel combustion synthesis method, was introduced to generate powerful radicals from peroxymonosulfate (PMS) for TMP degradation in an aqueous solution. The results showed that almost 90% of TMP was degraded within 24 min with the addition of 0.6 mM PMS and 0.2 g L−1 CuFe2O4/MWCNTs. The degradation rate was enhanced with the increase in initial PMS doses, catalyst loading and pH. A fairly low leaching of Cu and Fe was observed during the reaction, indicating the high potential recyclability and stability of CuFe2O4/MWCNTs. Electron paramagnetic resonance analysis confirmed that the CuFe2O4/MWCNT-PMS system had the capacity to generate ·OH and SO4˙−, whereas quenching experiments further confirmed that the catalytic reaction was dominated by SO4˙−. A total of 11 intermediate products of TMP was detected via mass spectrometry, and different transformation pathways were further proposed. Overall, this study showed a systematic evaluation regarding the degradation process of TMP by the CuFe2O4/MWCNT-PMS system.The degradation of trimethoprim (TMP) in heterogeneously activated peroxymonosulfate (PMS) oxidation processes using CuFe2O4/MWCNTs as the catalyst. |
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