SCIENCE OF THE TOTAL ENVIRONMENT
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2024
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IF 8.2
Shengnan Chen,Zhiwei Zhao,Li Li,Fuyi Cui
Ultrafiltration (UF) is widely used in drinking water plants, nevertheless, it still encounters challenges stemming from inevitable membrane fouling caused by natural organic matter (NOM). Herein, this work applied VUV/PS as UF membrane pretreatment and used UV/PS for comparison. VUV/PS system exhibited superior ability in removing NOM compared to UV/PS system. HO and SO 4 − played crucial roles in the degradation. [SO 4 − ]ss was notably higher than [HO ]ss in the systems, yet HO was of greater significance. [HO ]ss and [SO 4 − ]ss in the VUV/PS process were remarkably higher than those in the UV/PS process, due to the function of 185 nm photons. VUV/PS pretreatment basically recovered flux and effectively reduced fouling resistance, with better performance than UV/PS. Fouling mechanism was dominated by multiple mechanisms after UV/PS pretreatment, whereas it was transformed into pore blockage after VUV/PS pretreatment. Moreover, the UF effluent quality after VUV/PS pretreatment outperformed that of UV/PS but fell short of that without pretreatment, possibly due to the generation of abundant low MW substances under the action of HO and SO 4 − . After chlorine disinfection, UV/PS and VUV/PS pretreatments increased the DBPs production and cytotoxicity. Specifically, oxidant PS affected the membrane surface morphology and fouling behaviors, and had no obvious effect on interception performance and mechanical properties. In actual water treatment, VUV/PS and UV/PS pretreatments exhibited excellent performance in alleviating membrane fouling, improving water quality, and reducing DBPs formation and acute toxicity.
研究领域:
环境科学
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水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
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2022
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IF 8.943
Boqiang Li,Fei Yang,Baiyang Chen,Juan Li,Lijuan Zhu,Wen-Tao Li
Dissolved organic nitrogen (DON) plays a key role in many biogeochemistry and engineering processes such as forming nitrogenous disinfection byproducts . However, detecting aqueous DON at trace levels is challenging currently because conventional DON conversion methods have very high method detection limits (MDL). In addition, DON is measured indirectly by subtracting dissolved inorganic nitrogen (DIN) from total dissolved nitrogen (TDN), which can propagate analytical errors of each analyte. In order to solve these issues, we isolated DON from DIN with electrodialysis before and herein tested vacuum ultraviolet (VUV) in tandem with several oxidants to convert DON completely into nitrate for subsequent N analysis. Results showed that H 2 O 2 was more suitable than chlorine and persulfate because VUV/chlorine or VUV/persulfate is either inefficient to convert DON or subjected to nonnegligible N loss. To verify the efficiency, we evaluated the effects of typical water and operating variables on the conversions of four model DON compounds and their yields of nitrate. Under optimal conditions (pH 10.3 and 500 mg/L H 2 O 2 ), the process converted DON completely into nitrate within just 60 min. Compared to conventional TDN analytical methods, the VUV/H 2 O 2 method features not only better analytical precision but also lower MDL because the formed nitrate can be analyzed at very low MDL by ion chromatography (IC). So, this approach moves one step further to achieve a conceptually new DON analytical method by coupling electrodialysis, VUV/H 2 O 2 , and IC.
研究领域:
环境科学
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分析化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2017
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IF 6.216
Yujie Zhan,Jian Ji,Haibao Huang,Miao He,Dennis Y.C. Leung,Shuilian Liu,Yajie Shu,Qiuyu Feng,Ruijie Xie,Ruimei Fang,Xinguo Ye
Catalytic oxidation and AOPs normally require catalysts or chemical oxidants during VOCs degradation, making these processes costly and complex. We herein developed a facile system, VUV photolysis in pure water (VUV/H 2 O), for efficient VOCs degradation without auxiliary substances. The performance and mechanism of this system was intensively studied through controlling reaction conditions, detecting intermediates and analyzing reaction process during toluene degradation. Compared with direct VUV photolysis of gaseous toluene (VUV/Gas), the VUV/H 2 O system exhibited higher removal efficiency (83%) and mineralization rate (80%) of gaseous toluene bubbled into the system. In addition, no O 3 and gaseous byproducts were detected in the outlet gas stream. The excellent performance of VUV/H 2 O was attributed to the generation of more ·OH from the VUV photolysis of water and the continuous degradation of accumulated intermediates dissolved in water. The high CO 2 yield under an air atmosphere demonstrated that the dissolved oxygen in the water was essential for toluene mineralization since it was involved in the ring-fragmentation of toluene. According to various radicals and organic intermediates detected, possible pathway of toluene degradation in the VUV/H 2 O system was also proposed, which include OH addition, hydrogen abstraction and isomerization. The water after reaction can be effectively purified by sustaining VUV irradiation. This study presents a facile VUV/H 2 O system without auxiliary substances for efficient VOCs degradation and provides an insight into its degradation mechanism.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Shengnan Chen,Zhiwei Zhao,Chuang Wang,Fuyi Cui
Ultrafiltration (UF) is widely used in drinking water plants; however, membrane fouling is unavoidable. Natural organic matter (NOM) is commonly considered as an important pollutant that causes membrane fouling. Herein, we proposed VUV/H 2 O 2 as a UF pretreatment and used UV/H 2 O 2 for comparison. Compared to UV/H 2 O 2 , the VUV/H 2 O 2 system presented superior NOM removal. In the VUV/H 2 O 2 system, the steady-state concentration of HO• was approximately twice that in the UV/H 2 O 2 system, which was ascribed to the promoting effect of the 185 nm photons. Specifically, 185 nm photons promoted HO• generation by decomposing mainly H 2 O at a low H 2 O 2 dose or by decomposing mainly H 2 O 2 at a high H 2 O 2 dose. The VUV/H 2 O 2 pretreatment also demonstrated better membrane fouling mitigation performance than did UV/H 2 O 2 . An increase in the H 2 O 2 dose promoted HO• generation, thereby enhancing the performance of NOM degradation and membrane fouling alleviation and shifting the major membrane fouling mechanism from cake filtration to standard blocking. The VUV/H 2 O 2 (0.60 mM) pretreatment effectively reduced disinfection byproducts (DBPs) formation during chlorine disinfection. Additionally, the oxidant H 2 O 2 affected the membrane surface morphology and performance but had no evident effect on the mechanical properties. In actual water treatment, the VUV/H 2 O 2 pretreatment exhibited better performance than the UV/H 2 O 2 pretreatment in easing membrane fouling, ameliorating water quality, and reducing DBPs formation and acute toxicity.
研究领域:
环境科学
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水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2022
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IF 8.91
Nan Huang,Wan-Ting Shao,Wen-Long Wang,Qi Wang,Zhi-Qiang Chen,Qian-Yuan Wu,Hong-Ying Hu
Methylisothiazolinone (MIT) is frequently used as antimicrobial in household and industrial products, and poses ecological and health risks to aquatic organisms and humans. In this study, vacuum ultraviolet (VUV)/ultraviolet (UV) irradiation was found highly efficient for removal of MIT. The rate constant of MIT degradation ( k obs ) under VUV/UV irradiation was 3.75 μEinstein −1 cm 2 , which was around 12.5 times higher than that under UV irradiation. The •OH concentration during the VUV/UV process was 1.0 × 10 −12 M. The contributions of UV photolysis and •OH oxidation to MIT degradation under VUV/UV irradiation were 7.3% and 92.7%, respectively. The optimum solution pH (6.0–7.1) gave k obs 33%–39% higher than those at pH 3.9 and 9.3. CO 3 2− /HCO 3 − inhibited MIT degradation and the k obs decreased by 74% when the concentration of CO 3 2− /HCO 3 − was increased to 1 mM. The order of MIT removal efficiency under VUV/UV irradiation was ultrapure water > secondary effluent > reverse osmosis (RO) concentrate, because of the light screening and •OH quenching effect of actual wastewater. In RO concentrate, the rate constant of MIT degradation under VUV/UV irradiation was 22% higher than that obtained under UV irradiation. The reduction of TOC , UV 254 , and total fluorescence regional integration of the RO concentrate during VUV/UV process were 7.2%, 34.9%, and 52.3%, respectively. Twelve main transformation products of MIT were identified after VUV/UV degradation. The main degradation mechanisms of MIT were sulfur atom oxidation and hydroxyl addition. Quantitative structure–activity relationship analysis showed that VUV/UV degradation was an efficient method to remove the toxicity of MIT.
研究领域:
环境科学
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水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Bin Zhang,Jun Ma,Huizhong Chi,An Ding,Yanjun Xin,Yingying Ma,Qingliang Liu,Xu He
Given the limitations of conventional vacuum ultraviolet (VUV) systems, a novel vacuum ultraviolet/graphite carbon nitride (VUV/g-C 3 N 4 ) system with high adaptability to varying environmental conditions was developed. Compared with conventional VUV and UV/g-C 3 N 4 systems, the VUV/g-C 3 N 4 system demonstrates a much higher ability for the efficient degradation of chlorophenols (CPs). In particular, the VUV/g-C 3 N 4 system exhibits outstanding performance even at low pH and high concentrations of humic acid and SO 4 2- . Alkaline conditions and the presence of HCO 3 - can further promote CP removal. In addition, the feasibility of the VUV/g-C 3 N 4 system was verified by its stable operation in both river water and tap water . Unlike conventional photochemical systems relying on •OH, the dominant reactive species for CP degradation by the VUV/g-C 3 N 4 system was identified to be •O 2 - . This study conclusively provided a novel system for the efficient photocatalytic treatment of pollutants.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Cong Geng,Zhijie Liang,Fuyi Cui,Zhiwei Zhao,Chen Yuan,Jinying Du,Chuang Wang
Due to the inefficient treatment by the biotic and UV-disinfection processes in wastewater treatment plants, the broad-spectrum Fluoroquinolone antibiotics (FQs) are frequently detected in water environment around the world. In this work, the photo-degradation of three FQs (norfloxacin-NOR, ciprofloxacin-CIP, levofloxacin-LEV) by VUV/UV irradiation was investigated. The results showed that the degradation of FQs in VUV/UV irradiation system were more effective than that in UV irradiation system by enhanced the defluorination and decarboxylation . FQs could be degraded more efficiently with high temperature and low initial concentration, and the effect of flow rate was small. Initial pH played a key role in degradation of NOR and CIP. Most anions could slightly affect the FQs removal in water, except the carbonate and phosphate species. 1 O 2 and ·OH played the primary role in FQs degradation in VUV/UV system. Defluorination, decarboxylation, and piperazine ring oxidation were the main degradation pathways for three FQs degradation, but demethylation was a particular degradation pathway of LEV. Antibacterial activities of FQs aqueous sample were reduced in both VUV/UV and UV system, while the removal of antibacterial activities in the VUV/UV process were more efficient than UV process for NOR and LEV. VUV/UV system was more energy-saving for removing FQs. These results suggested that VUV/UV system is potential alternative in replacing or enhancing UV system in wastewater treatment plants for FQs removal in the future.
研究领域:
环境科学
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水处理工程
✓ 已验证
产品关联
DOI
高影响因子
Chemical Engineering Journal Advances
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2020
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IF 0
Hanlu Yan,Minghan Luo,Qiuwen Chen,Taeseop Jeong,Jianyun Zhang,Li Wang
Eliminating tetracycline antibiotics from waste streams by conventional water treatment techniques remains challenging. Vacuum-ultraviolet/ultraviolet (VUV/UV)-based advanced oxidation technique is a promising, environment-friendly alternative to remove micropollutants from wastewater without adding chemicals. This study carried out flow-through experiments and numerical modeling to determine the efficiency and mechanism of VUV/UV process in degrading oxytetracycline (OTC) via a newly developed photoreactor with tangential inlet and outlet. OTC degradation pathway and reaction rate constant were identified through semi-batch experiments at various initial OTC concentrations in different water matrices. The decomposition of OTC by the VUV/UV process was as effective as that by the H 2 O 2 /UV approach but generated less byproducts and thus could be beneficial for process control. Removal of organic matter and inorganic ions were suggested before VUV/UV process to improve the treatment efficiency. Flow characteristics simulated by computational fluid dynamics (CFD) revealed that a special bidirectional spiral flow was formed in the new reactor, which improved the mixing efficiency of fluids and thus enhanced the contact between hydroxyl radicals and the contaminant. The distribution profiles of OTC and hydroxyl radicals confirmed that the target contaminant was decomposed following the flow direction, and the degradation efficiency could be further increased by decreasing the internal diameter of the photoreactor. The electrical energy-per-order analysis of the photoreactor proved the high-energy utilization efficiency and cost-effectiveness of the VUV/UV process.
研究领域:
环境科学
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水处理工程
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化学工程
✓ 已验证
DOI
JOURNAL OF HAZARDOUS MATERIALS
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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
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水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Water Process Engineering
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2020
·
IF 3.465
Zhuang Lin,Wenlei Qin,Lei Sun,Xiangjuan Yuan,Dongsheng Xia
The degradation of Bisphenol A (BPA) in the vacuum ultraviolet/ ultraviolet/ peroxymonosulfate (VUV/UV/PMS) process based on a mini-fluidic VUV/UV photoreaction system has been comprehensively investigated focusing on the degradation performances and kinetics in this study. With 20 min reaction at pH 7.0 in VUV/UV/PMS process, the removal efficiency and the apparent degradation rate constant ( k app ) of BPA were > 95.2 % and 0.145 min −1 (R 2 = 0.9935). In addition, the impacts of operational parameters and co-existing constituents on BPA degradation are systematically evaluated. Importantly, the effective degradation of BPA (> 96.1 % at least) achieved at the test pH conditions (5–11) after 30 min reaction and achieved the highest BPA removal rate at pH = 11 (0.243 min −1 , R 2 = 0.9952). The electron paramagnetic resonance and radical scavenger experiments confirmed that both hydroxyl radical ( OH) and sulfate radical (SO 4 − ) are the predominant reactive radicals in VUV/UV/PMS process. The second-order reaction rate constants of BPA with OH and SO 4 − under different pH conditions were determined to be 0.74–1.86 × 10 10 M −1 s −1 and 2.92–5.01 × 10 9 M −1 s −1 via the competition kinetics. Meanwhile, the relative contribution rate of OH decreased from 97.2 %–33.1 % with the increasement of pH from 5.0 to 11.0, while the relative contribution rate of SO 4 − rose from 1.7 % to 48.9 %. The present study demonstrated that the VUV/UV/PMS process, as a new advanced oxidation process, has potential applications for micropollutants removal in water.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Wen-Long Wang,Zi-Bo Jing,Yi-Lin Zhang,Qian-Yuan Wu,Jörg E. Drewes,Min-Yong Lee,Uwe Hübner
Low-pressure mercury lamps with high-purity quartz can emit both vacuum-UV (VUV, 185 nm) and UV (254 nm) and are commercially available and promising for eliminating recalcitrant organic pollutants. The feasibility of VUV/UV as a chemical-free oxidation process was verified and quantitatively assessed by the concept of H2O2 equivalence (EQH2O2), at which UV/H2O2 showed the same performance as VUV/UV for the degradation of trace organic contaminants (TOrCs). Although VUV showed superior H2O activation and oxidation performance, its performance highly varied as a function of light path length (Lp) in water, while that of UV/H2O2 proportionally decreased with decreasing H2O2 dose regardless of Lp. On increasing Lp from 1.0 to 3.0 cm, the EQH2O2 of VUV/UV decreased from 0.81 to 0.22 mM H2O2. Chloride and nitrate hardly influenced UV/H2O2, but they dramatically inhibited VUV/UV. The competitive absorbance of VUV by chloride and nitrate was verified as the main reason. The inhibitory effect was partially compensated by •OH formation from the propagation reactions of chloride or nitrate VUV photolysis, which was verified by kinetic modeling in Kintecus. In water with an Lp of 2.0 cm, the EQH2O2 of VUV/UV decreased from 0.43 to 0.17 mM (60.8% decrease) on increasing the chloride concentration from 0 to 15 mM and to 0.20 mM (53.5% decrease) at 4 mM nitrate. The results of this study provide a comprehensive understanding of VUV/UV oxidation in comparison to UV/H2O2, which underscores the suitability and efficiency of chemical-free oxidation with VUV/UV.
研究领域:
环境工程
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水处理
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Jianyong Feng,Xing Li,Hang Li,Yanling Yang
Membrane biofouling is a challenge for biocarriers facilitated gravity-driven membrane (GDM) systems to achieve high-efficiency filtration in decentralized drinking water treatment . The purpose of this study was to investigate the effects of vacuum ultraviolet (VUV) as a pretreatment on membrane fouling , permeate water quality and bacterial communities. VUV pretreatment was found to significantly reduce the cake layer resistance by 24.4% and the membrane pore resistance by 40.0% ( p < 0.05), resulting in a 22.2% increase in stable flux. The removal of low molecular weight neutrals and protein-like materials was enhanced by 22.5% and 40.1% respectively after VUV pretreatment. The heterogeneity of the biofouling layer was improved by VUV pretreatment, and the porosity and roughness were increased by 227.5% and 46.5%, respectively. The application of VUV pretreatment resulted in a larger nanoparticle size in the biofouling layer suspension (peak at 85.4 nm), improvement in the membrane hydrophilicity, and a decrease in protein-like substances adhesion. The richness and diversity of the bacterial community were decreased by VUV pretreatment. The bacterial community structure had the highest mantel correlation with biopolymers (r = 0.89). Overall, VUV pretreatment can be a promising strategy to effectively alleviate membrane biofouling in biocarriers facilitated GDM systems.
研究领域:
环境工程
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水处理技术
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微生物学
✓ 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）