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Hu C, Wu Y, Dong Z, Dong Z, Ji S, Hu L, Yang X, Liu H. Degradation of carbamazepine by the UVA-LED 365/ClO 2/NaClO process: Kinetics, mechanisms and DBPs yield. J Environ Sci (China) 2025; 148:399-408. [PMID: 39095175 DOI: 10.1016/j.jes.2024.01.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 08/04/2024]
Abstract
A mixed oxidant of chlorine dioxide (ClO2) and NaClO was often used in water treatment. A novel UVA-LED (365 nm)-activated mixed ClO2/NaClO process was proposed for the degradation of micropollutants in this study. Carbamazepine (CBZ) was selected as the target pollutant. Compared with the UVA365/ClO2 process, the UVA365/ClO2/NaClO process can improve the degradation of CBZ, with the rate constant increasing from 2.11×10-4 sec-1 to 2.74×10-4 sec-1. In addition, the consumption of oxidants in the UVA365/ClO2/NaClO process (73.67%) can also be lower than that of UVA365/NaClO (86.42%). When the NaClO ratio increased, both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA365/ClO2/NaClO process. The solution pH can affect the contribution of NaClO in the total oxidant ratio. When the pH range of 6.0-8.0, the combination process can generate more active species to promote the degradation of CBZ. The change of active species with oxidant molar ratio was investigated in the UVA365/ClO2/NaClO process. When ClO2 acted as the main oxidant, HO• and Cl• were the main active species, while when NaClO was the main oxidant, ClO• played a role in the system. Both chloride ion (Cl-), bicarbonate ion (HCO3-), and nitrate ion (NO3-) can promote the reaction system. As the concentration of NaClO in the reaction solution increased, the generation of chlorates will decrease. The UVA365/ClO2/NaClO process can effectively control the formation of volatile disinfection by-products (DBPs), and with the increase of ClO2 dosage, the formation of DBPs can also decrease.
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Affiliation(s)
- Chenyan Hu
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Yihui Wu
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China
| | - Zhengyu Dong
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Ziyi Dong
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China
| | - Shengjie Ji
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China
| | - Lili Hu
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China
| | - Xinyu Yang
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China
| | - Hao Liu
- College of Environmental and Chemical Engineering, Shanghai Engineering Research Center of Energy, Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China
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Wan D, Song G, Mi W, Tu X, Zhao Y, Bi Y. Insights into the Enhanced Photogeneration of Hydroxyl Radicals from Chlorinated Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:805-815. [PMID: 38156625 DOI: 10.1021/acs.est.3c08257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Free available chlorine has been and is being applied in global water treatment and readily reacts with dissolved organic matter (DOM) in aquatic environments, leading to the formation of chlorinated products. Chlorination enhances the photoreactivity of DOM, but the influence of chlorinated compounds on the photogeneration of hydroxyl radicals (•OH) has remained unexplored. In this study, a range of chlorinated carboxylate-substituted phenolic model compounds were employed to assess their •OH photogeneration capabilities. These compounds demonstrated a substantial capacity for •OH production, exhibiting quantum yields of 0.1-5.9 × 10-3 through direct photolysis under 305 nm and 0.2-9.5 × 10-3 through a triplet sensitizer (4-benzoylbenzoic acid)-inducing reaction under 365 nm LED irradiation. Moreover, the chlorinated compounds exhibited higher light absorption and •OH quantum yields compared to those of their unchlorinated counterparts. The •OH photogeneration capacity of these compounds exhibited a positive correlation with their triplet state one-electron oxidation potentials. Molecular-level compositional analysis revealed that aromatic structures rich in hydroxyl and carboxyl groups (e.g., O/C > 0.5 with H/C < 1.5) within DOM serve as crucial sources of •OH, and chlorination of these compounds significantly enhances their capacity to generate •OH upon irradiation. This study provides novel insights into the enhanced photogeneration of •OH from chlorinated DOM, which is helpful for understanding the fate of trace pollutants in chlorinated waters.
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Affiliation(s)
- Dong Wan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Gaofei Song
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Wujuan Mi
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Xiaojie Tu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Yafei Zhao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Yonghong Bi
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
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Characterization in Inhibitory Effectiveness of Carbamazepine in Voltage-Gated Na + and Erg-Mediated K + Currents in a Mouse Neural Crest-Derived (Neuro-2a) Cell Line. Int J Mol Sci 2022; 23:ijms23147892. [PMID: 35887240 PMCID: PMC9321339 DOI: 10.3390/ijms23147892] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/15/2022] [Accepted: 07/15/2022] [Indexed: 12/18/2022] Open
Abstract
Carbamazepine (CBZ, Tegretol®) is an anticonvulsant used in the treatment of epilepsy and neuropathic pain; however, several unwanted effects of this drug have been noticed. Therefore, the regulatory actions of CBZ on ionic currents in electrically excitable cells need to be reappraised, although its efficacy in suppressing voltage-gated Na+ current (INa) has been disclosed. This study was undertaken to explore the modifications produced by CBZ on ionic currents (e.g., INa and erg-mediated K+ current [IK(erg)]) measured from Neuro-2a (N2a) cells. In these cells, we found that this drug differentially suppressed the peak (transient, INa(T)) and sustained (late, INa(L)) components of INa in a concentration-dependent manner with effective IC50 of 56 and 18 μM, respectively. The overall current–voltage relationship of INa(T) with or without the addition of CBZ remained unchanged; however, the strength (i.e., ∆area) in the window component of INa (INa(W)) evoked by the short ascending ramp pulse (Vramp) was overly lessened in the CBZ presence. Tefluthrin (Tef), a synthetic pyrethroid, known to stimulate INa, augmented the strength of the voltage-dependent hysteresis (Hys(V)) of persistent INa (INa(P)) in response to the isosceles-triangular Vramp; moreover, further application of CBZ attenuated Tef-mediated accentuation of INa(P)’s Hys(V). With a two-step voltage protocol, the recovery of INa(T) inactivation seen in Neuro-2a cells became progressively slowed by adding CBZ; however, the cumulative inhibition of INa(T) evoked by pulse train stimulation was enhanced during exposure to this drug. Neuro-2a-cell exposure to CBZ (100 μM), the magnitude of erg-mediated K+ current measured throughout the entire voltage-clamp steps applied was mildly inhibited. The docking results regarding the interaction of CBZ and voltage-gate Na+ (NaV) channel predicted the ability of CBZ to bind to some amino-acid residues in NaV due to the existence of a hydrogen bond or hydrophobic contact. It is conceivable from the current investigations that the INa (INa(T), INa(L), INa(W), and INa(P)) residing in Neuro-2a cells are susceptible to being suppressed by CBZ, and that its block on INa(L) is larger than that on INa(T). Collectively, the magnitude and gating of NaV channels produced by the CBZ presence might have an impact on its anticonvulsant and analgesic effects occurring in vivo.
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