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Degradation of tetracycline by medium pressure UV-activated peroxymonosulfate process: Influencing factors, degradation pathways, and toxicity evaluation
摘要： This study employed the medium pressure UV/peroxymonosulfate (MPUV/PMS), a new sulfate radical-based advanced oxidation process, to eliminate tetracycline (TTC) in water. At pH = 3.7, initial TTC concentration of 11.25 μM, PMS dosage of 0.2 mM and UV dose of 250 mJ cm-2, 82 % of TTC was degraded by MPUV/PMS. The second-order reaction rate constants of TTC with SO4?- and ?OH were found to be 1.4 × 1010 M-1 s-1 and 6.0 × 109 M-1 s-1, respectively. Radical quenching experiments indicated that ?OH played the major role in the degradation of TTC. Higher PMS dosage (0.1 mM~1.0 mM) and higher pH (3~11) could accelerate the TTC removal. Besides, the presence of Cl- (0.1 mM~5.0 mM) and CO32- (0.05 mM~0.5 mM) could also promote the reaction. Eight transformation products (TPs) were identified, and the potential degradation pathways mainly involved hydroxylation, demethylation and decarbonylation processes. The variation in the genotoxicity was investigated using the umu-test, and the results indicate that the genotoxicity of TTC after the MPUV/PMS treatment significantly increased during the initial stage. In addition, the ecotoxicity and mutagenicity of TTC and its TPs were predicted using quantitative structure-activity relationship (QSAR) analysis, and the results revealed that some TPs could have equivalent and even higher toxicity than TTC. MPUV/PMS showed better performance in TTC degradation in real waters than in Milli-Q water. MPUV/PMS is concluded to be an efficient method for removing TTC, but more attention should be paid to the changes of toxicity during this process.
关键词： Tetracycline,Toxicity,Hydroxyl radical,Sulfate radical,Transformation products
更新于2025-09-23 15:23:52
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UV-activated persulfate oxidation of 17β-estradiol: Implications for discharge water remediation
摘要： The female sexual hormone, 17β-estradiol (E2), was chosen as a model emerging contaminant to study its degradation kinetics using UV-activated persulfate (UV/PS). Our objective was to quantify the effectiveness of UV/PS coupled with slow-release technology to degrade E2 in real wastewater using a systematic design flow-through system. This was accomplished by quantifying the effects on E2 degradation rates of the initial PS or E2 concentration, initial pH, constituent ions, turbidity, humic acids, and real wastewater. The results showed that the E2 degradation rates increased with increasing PS concentration. The presence of other constituent ions (NO3–, Cl–, HCO3–) resulted in varying degradation rates due to the formation of active and less reactive radicals. Humic acid had higher significant impact on the rates than did turbidity. In addition, the observed degradation rates (0.140 min-1) in Deionized water were much higher than those observed in real wastewater matrix (0.001 min-1). Biodegradable soywax was the best binding agent that provided sustained delivery of PS thus resulting in better E2 removal than with other waxes. But treating E2 with PS soywax in a wastewater matrix, our flow-through system was able to maintain the E2 concentration below 50% in the contact tank (~150 min) and able to continually remove E2 up to 65% (~240 min) in the effluent reservoir. The overall results supported the use of UV-activated slow-release PS to treat discharge water in animal farming.
关键词： influencing factor,slow-release oxidant,17β-estradiol,UV activation,persulfate oxidation,sulfate radical
更新于2025-09-23 15:22:29
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Ultrasensitive Fluorescence Detection of Peroxymonosulfate Based on a Sulfate Radical-Mediated Aromatic Hydroxylation
摘要： Recently, peroxymonosulfate (PMS)-based advanced oxidation processes have exhibited broad application prospects in the field of environment. Accordingly, a simple, rapid and ultrasensitive method is highly desired for the specific recognition and accurate quantification of PMS in various aqueous solutions. In this work, SO4??-induced aromatic hydroxylation was explored, and based on that, for the first time, a novel fluorescence method was developed for the PMS determination using Co2+ as a PMS activator and benzoic acid (BA) as a chemical probe. Through a suite of spectral, chromatographic, and mass spectrometric analyses, SO4?? was proven to be the dominant radical species, and salicylic acid was identified as the fluorescent molecule. As a result, a whole radical chain reaction mechanism for the generation of salicylic acid in the BA/PMS/Co2+ system was proposed. This ?uorescence method possessed a rapid reaction equilibrium (< 1 min), an ultrahigh sensitivity (detection limit = 10 nM; quantification limit = 33 nM), an excellent specificity and a wide detection range (0–100 μM). Moreover, it performed well in the presence of possible interfering substances, including two other peroxides (i.e., peroxydisulfate and hydrogen peroxide), some common ions and organics. The detection results for real water samples further validated the practical utility of the developed fluorescence method. This work provides a new method for the specific recognition and sensitive determination of PMS in complex aqueous solutions.
关键词： benzoic acid,aromatic hydroxylation,fluorescence detection,sulfate radical,salicylic acid,peroxymonosulfate
更新于2025-09-09 09:28:46