JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Shengnan Chen,Zhiwei Zhao,Fuyi Cui,Bingyan Liu
Membrane fouling , primarily resulting from natural organic matter (NOM) widely existing in water sources, has always been a chief hindrance for the prevalent application of ultrafiltration (UF). Thus, vacuum ultraviolet (VUV)/chlorine process was proposed as a strategy for UF membrane fouling control and ultraviolet (UV)/chlorine process was used for comparison. VUV/chlorine process exhibited more excellent performance on NOM removal than UV/chlorine process. [HO•]ss and [Cl•]ss were calculated as 1.26 × 10 −13 and 3.06 × 10 −14 M, respectively, and ClO• might not exist under the conditions of 0.08 mM chlorine and 30 min VUV irradiation. [HO•]ss, [Cl•]ss and [ClO•]ss were not available and the formation of reactive radicals was unsustainable in UV/chlorine system. Moreover, VUV/chlorine pretreatment also showed better performance on the reversible and irreversible membrane fouling control than UV/chlorine pretreatment. The dominated fouling mechanism in the final stage of filtration was cake filtration. Additionally, the amount of detected disinfection by-products (DBPs) in VUV/chlorine system was significantly lower than that in UV/chlorine system. During subsequent chlorination disinfection, the yield of DBPs with VUV/chorine pretreatment was higher than that with UV/chlorine pretreatment. VUV/chlorine pretreatment could effectively control DBPs formation when the pretreatment time was extended to 120 min. In summary, VUV/chlorine system presented a most excellent performance on membrane fouling control, NOM degradation and DBPs control.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Diya Wen,Daoyi Chen,Yuelu Jiang
Unwanted proliferation of and adhesion by microalgae, as involved in fouling and species invasion, are important problems across many maritime operations and coastal industrial activities. The algicidal mechanisms of ultraviolet light-emitting diodes (UV-LEDs) and the synergistic algicidal effects between UV-LEDs and chlorine treatments in seawater were investigated in this study. Tetraselmis sp. was employed as the challenge organism. Five UV wavelengths (265, 280, 285, 300 and 315 nm) and three chlorine dosages (0.6, 0.8 and 1 mg L −1 ) were examined in a factorial experiment to optimize the disinfection performance achieved by combined UV-LED/chlorine treatments in seawater. Overall, the combined treatments showed a more effective inactivation of the microalgae than did the single treatments. Treatment with UV 285 combined with 0.8 mg L −1 chlorine resulted in 3.12-log inactivation at 100 mJ cm −2 (i.e. 2.34 Einsteins L -1 , 67 s). This optimal combination showed a higher inactivation rate constant and lower energy consumption (E E,2 ) than did the other treatments. The contribution of UV-LEDs, chlorine and hydroxyl radical (·OH) in the inactivation of Tetraselmis sp. by the combined UV-LED/chlorine disinfection process was investigated to illustrate the mechanism of this synergistic process, the results indicated that ·OH generated by photolysis were not the only contributors to the inactivation of the microalgae. Although a UV 300 /chlorine treatment demonstrated the highest chlorine photolysis rate, the inactivation constant of this treatment was lower than that of UV 285 /chlorine. These results demonstrated a synergistic algicidal effect of the combined disinfection system caused by exposure to the 285 nm UV-LED and low dosages of chlorine, which could provide an important basis for further developments and possibly industrial applications in the future.
研究领域:
海洋生物学
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环境科学
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微生物学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Nannan Wu,Wenrui Xiang,Feng Zhu,Zongli Huo,Zunyao Wang,Ruijuan Qu
This work was to investigate the transformation of coexisting decabromodiphenyl ether (BDE-209) on microplastics and their possible interactions in UV/chlorine process. Compared with pristine microplastics, the highly aged polystyrene (PS) showed an inhibitory effect on degradation of BDE-209. Increasing initial concentration of BDE-209 on PS inhibited degradation, while the chlorine concentration and pH did not affect the final degradation efficiency. Moreover, the presence of NO 3 − , SO 4 2− , HCO 3 − and HA in water was unfavorable for BDE-209 degradation. According to the experimental and calculation results, the contribution to the degradation of BDE-209 was ranked as direct photolysis > HO• > •Cl in the UV/ chlorine system. Chlorination products released by PS during UV/chlorination were detected. Four possible reaction pathways of BDE-209 were proposed, which mainly involved debromination, hydroxylation, chlorine substitution, cleavage of ether bond, and intramolecular elimination of HBr. It was worth noting that PS microplastics not only inhibited the degradation of BDE-209, but also affected the type and abundance of its transformation products. Meanwhile, interaction products of PS and BDE-209 were determined, which was attributed to reactions of PS-derived radicals with •Br/•C 6 Br 5 and •Cl. Results of toxicity evaluation showed that the introduction of carbon-halogen bonds, especially C-Br bond, increased the toxicity of chain scission products of PS. This work provides some new insights into transformation, interaction, and associated ecological risks of coexisting microplastics and surface adsorbed contaminants in the UV/chlorine process of drinking water treatment plants (DWTPs) and wastewater treatment plants (WWTPs).
研究领域:
环境科学
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毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Water
·
2019
·Vol. 11
·期 12
·2639
·
IF 2.524
Chi Wang,Zhian Ying,Ming Ma,Mingxin Huo,Wu Yang
The utilization of reclaimed water is a reliable and sustainable approach to enhance water supply in water-deficient cities. However, the presence of micro-organic pollutants (MPs) in reclaimed water has potential adverse effects on aquatic ecosystems and human health. In this study, we investigated the occurrence of 12 target MPs in the influent and reclaimed water collected from a local wastewater treatment plant, and the ultraviolet (UV)–chlorine process was applied to analyze its ability to remove MPs. The results showed that all 12 MPs were detected in both the influent and the reclaimed water, with the concentrations ranging from 25.5 to 238 ng/L and 8.6 to 42.5 ng/L, respectively. Over 52% of all the target MPs were readily degraded by the UV–chlorine process, and the removal efficiency was 7.7% to 64.2% higher than the corresponding removal efficiency by chlorination or UV irradiation only. The degradation efficiency increased with the increasing initial chlorine concentration. The pH value had a slight influence on the MP degradation and exhibited different trends for different MPs. The formation of known disinfectant byproducts (DBPs) during the UV–chlorine process was 33.8% to 68.4% of that in the chlorination process, but the DBPs’ formation potentials were 1.3 to 2.2 times higher. The toxicity assay indicated that UV–chlorine can effectively reduce the toxicity of reclaimed water.Keywords:MPs;UV–chlorine process;disinfectant byproducts;toxicity
研究领域:
环境科学
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水处理
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毒理学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2023
·
IF 8.6
Lingjun Bu,Xiaojun Chen,Yangtao Wu,Shiqing Zhou
Halonitrophenols (HNPs) are emerging aromatic nitrogenous disinfection by-products ( N -DBPs) with high cyto- and genotoxicity. However, limited information is available regarding the formation mechanism of HNP during chlorination after the UV/chlorine process. In the past, dissolved organic nitrogen (DON) constitutes a vast array of N -DBP precursors due to its heterogeneous nature. Amino acids (AAs) are an important class of DON in water, where combined AAs (i.e., peptides and proteins) make up a larger identifiable section. In this study, three AAs including free tyrosine (Tyr) and two oligopeptides (i.e., tyrosine-alanine (Tyr-Ala) and tyrosine-tyrosine-tyrosine (Tyr-Tyr-Tyr)) were selected as model AAs to evaluate the effect of the UV/chlorine process on the formation of 2,6-dichloro-4-nitrophenol (DCNP). We found an enhanced formation of DCNP after the UV/chlorine process in comparison with direct chlorination, which indicated the nitrogen sources in AAs can contribute to the formation of HNPs. The presence of NO • in the UV/chlorine process was demonstrated by electron spin-resonance spectroscopy (ESR) test. The effects of three typical factors (i.e., UV fluence, pH, and Cl 2 /AA) on the formation of DCNP in the UV/chlorine process were investigated to optimize parameters to minimize the formation of HNPs. Furthermore, it was observed that oligopeptides exhibited higher yields of DCNP than free Tyr. Based on this, we propose a possible formation pathway of DCNP from 2 oligopeptides to elucidate the formation mechanisms more intuitively. We observed and confirmed a convertible tendency from HNPs to aliphatic DBPs (e.g., trichloronitromethane). Overall, this study provided a reliable theoretical basis for a comprehensive understanding of the precursors, formation mechanisms and control methods of HNPs.
研究领域:
环境科学
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毒理学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Jinxiu Lou,Lu Yin,Feilong Dong,Zhanfei He,Huijie Lu,Shuangxi Fang,Xiangliang Pan
Nitrogenous disinfection byproducts (N-DBPs) are notorious for their serious health risks, yet nitrate (NO 3 - ) mediates N-DBPs generation during UV/chlorine treatment remains unexplored. This study investigated the interaction of chlorine and NO 3 - on N-DBPs formation and developed a specific fragment-based screening method using UPLC-QTOF-MS to explore the underlying mechanism. Results showed that the chlorine-to-nitrogen (Cl/NO 3 - -N) molar ratio significantly affects dichloroacetonitrile (DCAN) and dichloroacetamide (DCAM) generation, with peak concentrations at a Cl/NO 3 - -N molar ratio of around 15. NO 3 - promotes the production of HO • , which positively correlates with DCAN and DCAM concentrations, also peaking at this ratio. Utilizing our developed method, three key hydroxyl-substituted intermediates that circumvent the previously reported “limiting-steps” in DCAN formation were identified. This reaction proceeds via a stepwise mechanism involving hydroxylation and chlorine substitution to produce hydroxyl-phenylacetonitrile and hydroxyl-chlorine-phenylacetonitrile. The conversion rate of hydroxyl-chlorine-phenylacetonitrile to DCAN was 8.6 times higher at Cl/NO 3 - -N molar ratio of 15 compared to conditions without NO 3 - , attributed to the weakened bond strength of the side chain, as supported by density functional theory calculations. This study provides novel insights into the mechanistic pathways of DCAN and DCAM formation, critical for developing more effective drinking water disinfection technologies to control N-DBPs.
研究领域:
环境科学
·
饮用水处理
·
化学动力学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Xinran Zhang,Jun He,Shuqi Xiao,Xin Yang
Microcystin-LR (MC-LR), a toxin produced by cyanobacteria, is very toxic and poses a threat to public health when entering water treatment works. In this study, UV/chlorine process, as an advanced oxidation process (AOP), has been demonstrated for effective elimination of MC-LR levels and associated toxicity. At a chlorine dose of 3.0 mg L −1 and UV fluence of 125 mJ cm −2 , MC-LR (initial concentration 1.0 μM) was reduced by 92.5%, which was much higher than 20.3% removal under UV irradiation alone and 65.1% removal during dark chlorination. Enhanced degradation was attributed by hydroxyl radicals (HO ) and reactive chlorine species (RCS), mainly Cl 2 - and ClO . Increasing chlorine doses or lowering pH favored MC-LR removal. Increased bicarbonate and natural organic matter concentrations inhibited MC-LR removal, but bromide ions enhanced MC-LR removal instead. MC-LR elimination rates in natural waters were roughly two times smaller than those in ultrapure water. The reactive radicals promoted hydroxylation of both diene of Adda moiety and double bond of Mdha moiety in MC-LR. UV exposure enhanced the dechlorination of chloro-MC-LR via the cleavage of C Cl bond. The toxicity was evaluated by a protein phosphatase (PP2A) inhibition assay. At a chlorine dose of 3.0 mg L −1 and UV fluence of 125 mJ cm −2 , the toxicity of the treated water was reduced by 75.0%, which was also higher than 25.7% and 46.7% removal under UV irradiation alone and during dark chlorination, respectively. These results highlight UV/chlorine is an efficient AOP for MC-LR degradation and detoxification.
研究领域:
环境科学
·
水处理工程
·
毒理学
✓ 已验证
DOI
PubMed
高影响因子
ACS ES&T Engineering
·
2025
·
IF 6.7
Baoqiang Hao,Renyuan Zhang,Genye He,Zishi An,Xiaoqing Li,Jing Li
The combined application of UV254 irradiation and chlorination (UV/chlorine) is considered to be a promising method for the disinfection and removal of organic pollutants. However, it is not clear how this process affects the formation of disinfection by-products (DBPs). In this study, the formation of DBPs from 11 of the most commonly used azoles in the UV/chlorine process has been investigated. The study demonstrated that dichloroacetylene, a previously unreported DBP, was identified as a coproduct of azoles. In addition to dichloroacetylene, another toxic DBP, cyanogen chloride (CNCl), was also detected in the process. However, neither dichloroacetylene nor CNCl was detected in the presence of azoles during chlorination alone. The results indicated that •OH and •Cl radicals resulting from UV/chlorine were the key factors in the production of dichloroacetylene and CNCl. Further studies have shown that dichloroacetylene was relatively stable in water with a hydrolysis half-life of 77 h and can be degraded in the presence of UV irradiation or high doses of chlorine. Additionally, bromochloroacetylene was observed in the UV/chlorine system in the presence of bromide. Furthermore, the presence of dichloroacetylene was detected in real UV/chlorine-treated water samples at concentrations ranging from 0.06 to 0.18 μM. This was found to be significantly increased by the addition of pyrazole, as was the case with CNCl. Dichloroacetylene and CNCl were detected in wastewater treatment plants at concentrations ranging from 0.15 to 0.31 μM. This finding suggested that the active species of the UV/chlorine process may alter the DBP formation pathway and lead to the emergence of novel toxic DBPs that have not yet been identified.
研究领域:
环境科学
·
公共卫生
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Kai Yin,Yongxiu Deng,Chengbin Liu,Qunying He,Yuanfeng Wei,Shuo Chen,Tongcai Liu,Shenglian Luo
Although UV/chlorine advanced oxidation process has been employed to treat contaminants, the roles of secondary radicals are generally negligible. The comprehensive evaluation of secondary radicals on contaminants degradation remains deficient. In this study, two typical neonicotinoid insecticides, imidacloprid (IMD) and thiacloprid (THIA), were degraded via UV/chlorine process. It is for the first time found that the existence of Cl − significantly promoted THIA degradation during UV/chlorine process, attributed to the formation of Cl 2 − . In addition, the effects of pH, fulvic acid (FA), and bicarbonate (HCO 3 – ) on the degradation of IMD and THIA were evaluated. Low pH was in favor of the degradation of IMD and THIA, while both FA and HCO 3 – had slight inhibition effects. Meanwhile, the degradation of IMD and THIA via UV/chlorine process was inhibited in real matrices. The existence of Br − heavily suppressed the degradation of THIA via UV/chlorine process. The initial transformation pathways of IMD and THIA involved electron transfer, H-abstraction, and then disproportionation or the methylene bridge cleavage, yielding hydroxyl and keto derivatives as well as free amine. Although the mineralization for IMD (29%) and THIA (35%) was low, the acute toxicity to Vibrio fischeri for the treated samples was lower than that for corresponding parent compounds. This study comprehensively evaluated the degradation of IMD and THIA via UV/chlorine process, highlighting Cl 2 − as an important reactive species for THIA elimination.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
Environmental Technology & Innovation
·
2022
·
IF 7.758
Xinran Zhang,Pengfei Ren,Jianhua Zhou,Junyi Li,Zhenxing Li,Ding Wang
This study investigated the formation of disinfection byproducts (DBPs) from a real ammonia-polluted source water treated by a pilot-scale ultraviolet (UV)/chlorine process with subsequent post-chlorination. The experimental results indicated that UV/chlorine treatment enhanced the formation of trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitriles (HANs) in post-chlorination, compared to UV or chlorine applied alone under parallel experimental conditions. DBP formation was observed to depend on pH values, chlorine doses, and reaction times. THM formation was higher at pH 9.0 than pH 6.0, while HAAs and HANs were produced more readily at pH 6.0 rather than 9.0. A higher chlorine dose led to a higher amount of DBPs formed after the treatment of UV/chlorine followed by post-chlorination. The concentration of DBPs increased with the UV/chlorine treatment time increasing from 2 to 15 s and then presented a decrease trend with the reaction time prolonging to 30 s. In addition, changes in natural organic matter (NOM) properties were evaluated using three-dimensional fluorescence spectra and parallel factor analysis (PARAFAC) UV/chlorine treatment effectively destroyed humic-like and tyrosine-like components in waters with the maximum fluorescence intensity ( FI m a x ) reduced by 51.4% and 64.6%, respectively, compared to the raw water sample. The decrease of fluorescence of waters exhibited a positive correlation with the formation of DBP-FP in UV/chlorine treatment. Overall, DBP formation from the ammonia-polluted source water caused by UV/chlorine treatment could be managed by carefully determining chlorine doses and contact times to be used in the UV/chlorine process.
研究领域:
环境科学
·
公共卫生
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Baoqiang Hao,Yang Guo,Xueling Bai,Renyuan Zhang,Xiaoqing Li,Jing Li
The combined application of chlorination and UV irradiation has the potential to yield important benefits in water treatment. However, much of the fundamental chemistry that governs the behavior of UV/chlorine systems have not been well defined. Cyano-containing pesticides (CNPs) are widely used in agriculture and inevitably enter surface waters and other aquatic environments. In this study, twenty CNPs and their intermediates were investigated to evaluate the formation of disinfection byproducts under chlorination and UV/chlorine systems. It was found that UV/chlorine can significantly enhance the generation of cyanogen chloride (CNCl) and dichloroacetonitrile (DCAN) compared to chlorination alone. The CNCl and DCAN concentrations increased from an average of 0.13 and 0.12 μM during the chlorination alone to 0.85 and 0.41 μM, respectively, when UV 254 light was introduced. The maximum yields of CNCl and DCAN could reach 31.8 % and 7.7 %, respectively. Both the photo-induced • OH and • Cl played a key role in the generation of CNCl and DCAN. Additionally, higher yields of total CNX were observed in the UV/chlorine system in the presence of bromide. Similar results were obtained in the treatment of actual water samples, in which the concentrations of CNCl and DCAN increased by orders of magnitude under UV/chlorine treatment compared to the chlorination alone. The results showed that the cyano group of organic pollutants has a higher potential to be directly converted to toxic CNCl and DCAN under UV/chlorine treatment. The inclusion of this basic chemistry will deepen our understanding of UV/chorine water treatment technologies.
研究领域:
环境科学
·
水处理化学
·
毒理学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）