WATER RESEARCH
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2016
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IF 5.991
Wen-Long Wang,Qian-Yuan Wu,Nan Huang,Ting Wang,Hong-Ying Hu
For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants . In this study, the synergistic treatment with UV irradiation and chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species ( OH and Cl), and this process could be well depicted by pseudo first order kinetic. The degradation rate constants ( k obs,CBZ ) of CBZ increased linearly with increasing UV irradiance and chlorine dosage. The degradation of CBZ by UV/chlorine in acidic solutions was more efficient than that in basic solutions mainly due to the effect of pH on the dissociation of HOCl and OCl − and then on the quantum yields and radical species quenching of UV/chlorine. When pH was increased from 5.5 to 9.5, the rate constants of degradation of CBZ by OH decreased from 0.65 to 0.14 min −1 and that by Cl decreased from 0.40 to 0.11 min −1 . The rate constant for the reaction between Cl and CBZ was 5.6 ± 1.6 × 10 10 M −1 s −1 . Anions of HCO 3 − (1–50 mM) showed moderate inhibition of CBZ degradation by UV/chlorine, while Cl − did not. UV/chlorine could efficiently degrade CBZ in wastewater treatment plant effluent, although the degradation was inhibited by about 30% compared with that in ultrapure water with chlorine dosage of 0.14–0.56 mM. Nine main oxidation products of the CBZ degradation by UV/chlorine were identified using the HPLC-QToF MS/MS. Initial oxidation products arose from hydroxylation, carboxylation and hydrogen atom abstraction of CBZ by OH and Cl, and were then further oxidized to generate acylamino cleavage and decarboxylation products of acridine and acridione.
研究领域:
环境科学
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水处理
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化学工程
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
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2023
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IF 11.1
Qi Wang,Nan Huang,Wenlong Wang,Yunpeng Wu,Song Xue,Hongwei Xu,Zhuo Chen,Yinhu Wu,Qianyuan Wu,Hongying Hu
Urea in the ultrapure water production process threatens semiconductor manufacturing . This work proposed a urea removal strategy involving the VUV/UV/chlorine process in an acidic solution to achieve high-efficiency urea removal. VUV/UV/chlorine could thoroughly remove urea of 2 mg/L within 9 min at pH 3. A TN removal rate of 70% and a dissolved organic carbon removal rate of 84% were achieved in the urea degradation process . The decrease in pH and the increase in oxidant dosage could improve urea removal efficiency. The presence of chloride anion could improve urea removal by 55–85%. Based on the radical probe and quenching experiments, free radicals accounted for more than 90% of urea removal. •Cl 2 − and •OH were calculated to contribute approximately 36% and 22%, respectively, to urea removal. •Cl and •ClO together contributed less than 32%. The chlorination of urea was responsible for less than 10% of urea removal. Nitrogen in urea was transformed efficiently into inorganic nitrogen (N 2 , ammonium, and nitrate with a rough ratio of 6:1:1.1). Organic chlorine products formed in the urea degradation process took up less than 3% in all chlorine element and was converted into chloride anion finally.
研究领域:
环境科学
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水处理
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
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2020
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IF 9.13
Yinqiao Zhang,Huijiao Wang,Yang Li,Bin Wang,Jun Huang,Shubo Deng,Gang Yu,Yujue Wang
The ultraviolet/chlorine (UV/Cl 2 ) process is an emerging advanced oxidation technology for micropollutant abatement in water and wastewater treatment . However, the application of the conventional UV/Cl 2 process in decentralized systems is limited by the transport and management of liquid chlorine. To overcome this limitation, this study evaluated an electrochemically driven UV/Cl 2 (E-UV/Cl 2 ) process for micropollutant abatement under conditions simulating decentralized water treatment . The E-UV/Cl 2 process combines UV irradiation with in situ electrochemical Cl 2 production from anodic oxidation of chloride (Cl − ) in source waters. The results show that with typical Cl − concentrations present in water sources for decentralized systems (30–300 mg/L Cl − ), sufficient amounts of chlorine could be quickly electrochemically produced at the anode to enable E-UV/Cl 2 process for water treatment. Due to its multiple mechanisms for micropollutant abatement (direct photolysis, direct electrolysis, Cl 2 -mediated oxidation, as well as hydroxyl radical and reactive chlorine species oxidation), the E-UV/Cl 2 process effectively eliminated all micropollutants (trimethoprim, ciprofloxacin, metoprolol, and carbamazepine) spiked in a surface water in 5 min. In contrast, at least one micropollutant with ∼20–80% residual concentrations could still be detected in the water treated by 10 min of UV irradiation, chlorination, electrolysis, and the conventional UV/Cl 2 process under similar experimental conditions. The electrical energy per order (E EO ) for micropollutant abatement ranged from 0.15 to 1.8 kWh/m 3 for the E-UV/Cl 2 process, which is generally comparable to that for the conventional UV/Cl 2 process (0.14–2.7 kWh/m 3 ). These results suggest that by in-situ generating Cl 2 from anodic oxidation of Cl − , the E-UV/Cl 2 process can overcome the barrier of the conventional UV/Cl 2 process and thus provide a promising technology for micropollutant abatement in decentralized water treatment systems.
研究领域:
环境科学
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水处理
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化学工程
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电化学
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高级氧化工艺
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
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2024
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IF 11.4
Qi Lu,Qi Han,Hongnan Liu,Li Feng,Yongze Liu,Ziwen Du,Liqiu Zhang
Dissolved black carbon (DBC) released from biochar, is an essential group in the dissolved organic matter (DOM) pool and is widely distributed in aquatic environments. In various advanced oxidation processes (AOPs), DBC exhibits enhanced free radical scavenging compared to typical DOM, attributed to its smaller molecular weight and more compacted aromatic structure; however, the molecular-level transformations of DBC in different AOPs , such as UV/H 2 O 2 , UV/PDS, and UV/Chlorine, remain unclear. This study employed a DBC derived from wheat biochar for experimentation. Characterization involved ultraviolet-visible (UV–Vis) spectroscopy and fluorescence excitation-emission-matrix (EEM) spectroscopy, revealing the transformation of DBC through diminished SUVA 254 values and reduced intensity of three-dimensional fluorescence peaks. Further insights into the transformation were gained through Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). After each UV-AOP treatment, a conspicuous augmentation in the oxygen content of DBC was observed. The detailed oxygenation processes were elucidated through mass difference analysis, based on 23 types of typical reactions. Results indicated that oxygenation reactions were most frequently detected in all three UV-AOP treatments. Specifically, the hydroxylation (+O) predominated in UV/H 2 O 2 , while the di-hydroxylation (+2O) prevailed in UV/PDS. UV/Chlorine treatments commonly exhibited tri-hydroxylation (+3O), with the identification of 1194 Cl-BPs of unknown structures. This study contributes to a comprehensive understanding of the molecular transformations of DBC induced by various free radicals in different UV-AOP processes, leading to a better understanding of the different fates of DBC in UV-AOP processes. In addition, the identification of DBC as a precursor of by-products will also contribute to the understanding of how to inhibit the generation of by-products.
研究领域:
环境科学
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化学工程
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分析化学
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水处理
✓ 已验证
DOI
PubMed
高影响因子
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