SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Jiayu Du,Decai Liu,Zhiyong Zhang,Huiying Ai,Ming-Lai Fu,Wenjie Sun,Baoling Yuan
The widespread use of chlorine during disinfection has led to the problems of disinfection by-products (DBPs). Recently, the combination of ultraviolet (UV, 254 nm) and vacuum ultraviolet (VUV, 185 nm) with chlorine has been considered a promising strategy to mitigate the formation of DBPs. This study systematically evaluated the efficacy of six different disinfection methods in abating humic acid (HA), a common precursor of DBPs (UV-Chlorine, VUV/UV-Chlorine, Chlorine-UV, Chlorine-VUV/UV, UV/Chlorine, and VUV/UV/Chlorine). Under 40 mJ/cm 2 UV fluence and 3 mg/L chlorine dose, the synergistic processes yielded DBP levels below 20 μg/L, whereas sequential disinfection resulted in DBP levels exceeding 100 μg/L. Additionally, there was no significant difference in the formation of DBPs between the two methods of chlorination followed by irradiation. However, for irradiation followed by chlorination, the addition of VUV led to an increase of 50 μg/L in trihalomethanes (THMs). As the irradiation time increased, the inclusion of VUV demonstrated enhanced control of DBP levels in the sequential disinfection process. Moreover, compared to UV/Chlorine, at 13 mg/L chlorine dose in VUV/UV/Chlorine process, the inclusion of VUV expedited the appearance of peak DBPs by two minutes and reduced the peak value by 25.6 %, but the DBP yield was 12.9 times higher than that at a chlorine dose of 3 mg/L. This study, comparing six combination disinfection methods, will provide deeper insights into precursor abatement and DBP control during drinking water disinfection.
研究领域:
环境科学
·
公共卫生
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2021
·
IF 6.498
Juan Li,Qi Zhang,Baiyang Chen,Lei Wang,Rongshu Zhu,Jie Yang
Understanding the formation and transformation of radicals generated by a low pressure mercury lamp emitting both 254 nm ultraviolet (UV 254 ) and 185 nm vacuum UV (VUV 185 ) is currently challenging due to the complexity of concurrent redox reactions occurring in this complex system. Because hydrogen peroxide (H 2 O 2 ) is a common product of both oxidizing and reducing radicals generated during the VUV irradiation process, monitoring the variations in H 2 O 2 levels can help us better understand the presence and relative dominance of different radicals. In this study, we systematically evaluated the effects of several selected anions on the formation of H 2 O 2 under a variety of pH and dissolved oxygen (DO) conditions. Results show that although addition of these anions inhibited the formation of H 2 O 2 , their H 2 O 2 -inhibition mechanisms are markedly different. At low concentrations (≤1.0 mg/L), chloride reduced the generation of H 2 O 2 primarily by consuming hydroxyl radicals (•OH); however, in high concentrations (11.0 mg/L), its light-screening effect was dominant. In comparison, the presence of bromide (≤1.0 mg/L) inhibited H 2 O 2 formation mainly by reacting rapidly with both •OH and H 2 O 2 . Carbonate and phosphorous species exerted influence mainly by consuming •OH. Along with irradiation, increasing pH significantly decreased H 2 O 2 levels, confirming that H 2 O 2 was formed mainly by •OH. In contrast, raising DO did not raise H 2 O 2 maximum yields, confirming that reducing radicals like aqueous electrons (e - aq ) and hydrogen atoms (•H) are not the key precursors of H 2 O 2 in this process. Mathematically, the evolutions of H 2 O 2 can be reliably modeled (R 2 ≥ 0.80) using a kinetics model incorporating H 2 O 2 formation and decomposition kinetics. The results of this study may contribute to better understanding the use of VUV technology in water/wastewater treatment.
研究领域:
环境科学
·
水处理技术
✓ 已验证
DOI
PubMed
高影响因子
WATER RESEARCH
·
2022
·
IF 13.4
Huimei Pan,Yuanxi Huang,Juan Li,Boqiang Li,Yang Yang,Baiyang Chen,Rongshu Zhu
Haloacetaldehydes (HALs) are the third largest disinfection by-product (DBP) ubiquitously detected in finished drinking water and have relatively higher toxicity than currently regulated DBPs. To efficiently alleviate them, this study investigated a green, chemical-free technology by using ultraviolet/vacuum ultraviolet (UV/VUV) on degrading three refractory chlorinated HALs (Cl-HALs). The results indicate that the rates of Cl-HALs decomposition in tap water irradiated by UV/VUV were 23–70 times higher than those irradiated by UV, proving that VUV instead of UV played the key role in degrading Cl-HALs. Increasing Cl-HALs dosage, pH, and dissolved oxygen (DO) all decreased the Cl-HALs degradations significantly, and the rates in tap water were apparently lower than those in ultrapure water. Unlike previous studies, this study proved that both oxidation and reduction were present during the VUV process. Photooxidation via oxidative radicals like •OH mineralized Cl-HALs, leading to substantial drops of total organic carbon ; photoreduction via reductive radicals like •H dehalogenated Cl-HALs, resulting in formation of considerable intermediate organics (e.g., formic acid and acetic acid). No matter what pathway, the mass balances of chlorine were always maintained, meaning that dehalogenation occurred instantaneously rather than sequentially. Although the overall photodegradation rates dropped with rising pH and DO, photoreduction was increased with rising pH while photooxidation was elevated with rising DO. The results hence provide insights to better understand the VUV technology in controlling micropollutants in water.
研究领域:
环境科学
·
水处理技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Dong Wen,Wentao Li,Jinrong Lv,Zhimin Qiang,Mengkai Li
This study investigated methylene blue (MB) degradation by the vacuum-ultraviolet/ultraviolet/persulfate (VUV/UV/PS) process using a mini-fluidic VUV/UV photoreaction system. Results show that MB degradation by the VUV/UV/PS process was significantly higher than that of the conventional UV/PS process, as the VUV photolysis of H 2 O and PS generated more reactive oxygen species (ROSs). HO • and SO 4 •− , identified as the main ROSs, were mostly consumed by dissolved organic carbon and Cl ‒ in real waters, respectively. Additionally, the impacts of solution pH and the concentrations of PS, humic acid, and inorganic ions (HCO 3 ‒ , Cl ‒ , NO 3 ‒ , SO 4 2‒ , Fe(II), and Fe(III)) were systematically evaluated. The solution pH significantly affected the photon absorption distributions, as well as the contributions of photolysis and oxidation to MB degradation, resulting in different variations in the degradation rate constant and total organic carbon removal ratio with increasing solution pH. At all tested pH levels (3.0–11.0), particularly under acidic conditions, HO and SO 4 − were two predominant contributors to MB degradation, while VUV and UV photolysis contributed more when the solution pH increased. This study provides a highly efficient process for organic pollutant removal, which could be applied in water treatment.
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
Advanced Materials Technologies
·
2017
·Vol. 2
·期 12
·1700221
·
IF 0
Kai Song,Nan Ma,Ya Yang
Semiconductor materials based UV photodetectors can be operated via photovoltaic effect by converting UV light into electric signals. Recent studies have been focused on how to fabricate excellent semiconductor materials based photodetectors through construction of heterojunctions, which may not be suitable for practical large-scale devices due to the high cost and sophisticated fabrication process. Here, by utilizing naturally existing temperature change of UV illumination and the pyroelectric effect of ferroelectric materials, a novel self-powered UV photodetector based on Pb(Zr,Ti)O 3 (PZT) material is presented through a simple fabricating process, which can be well utilized to detect 365 nm UV light by using light-induced temperature variation. Under a temperature change rate of 2.40 K s −1 , the voltage response and the corresponding responsivity can be enhanced by larger than 6600% as compared with that of individual UV light illumination. This study provides a feasible solution to realize self-powered UV light detection by utilizing light-induced pyroelectric effect in PZT.
研究领域:
材料科学
·
光子学
·
电气工程
✓ 已验证
产品关联
DOI
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Hang Li,Yanling Yang,Jiawei Ren,Zhiwei Zhou,Xing Li,Yuankun Liu,Jianyong Feng
Pre-ozonation is often used as an effective method to assist coagulation in removing organic contaminants . In this study, a new process that combining ozone (O 3 ) with vacuum ultraviolet (VUV/UV) process (VUV/UV/O 3 ) is investigated to enhance the removal of organic matters in greywater from public buildings or household. The influence of organic characteristics (molecular weight distribution, hydrophobicity , and fluorescence) in greywater on VUV/UV/O 3 enhanced coagulation has not been fully studied. Herein, organic matters of greywater were separated and classified, and fates of organic fractions by VUV/UV/O 3 enhanced coagulation were clarified. Greywater contains tryptophan-like and tyrosine-like proteins, and terrestrially derived humic-like substances. The highest UV 254 , LAS , DOC and COD Cr removal efficiency from greywater could reach up to 47.54%, 58.92%, 17.96% and 15.76% in VUV/UV/O 3 enhanced coagulation, respectively. The removal efficiency of tryptophan-like and tyrosine-like in filtrates of varied molecular weight ranges by VUV/UV/O 3 enhanced coagulation was 93.59%–98.13% and 89.86%–95.53%, respectively. VUV/UV/O 3 enhanced coagulation was effective for the removal of bio-polymers, humic substances and low molecular weight acid ≤ 30 kDa, while it was insignificant for that of 0.22 µm - 100 kDa. Particle size of flocs increased significantly in filtrates obtained from increasing membrane pore size, indicating that macromolecular organic matter was more likely to form flocs. Finally, the VUV/UV/O 3 could improve coagulation on the removal of varied organic pollutants and improve sedimentation by changing the flaky flocs to dense ones. Therefore, the results demonstrate VUV/UV/O 3 is an effective pre-oxidation method to enhance the effect of coagulation on greywater treatment.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2017
·Vol. 7
·期 8
·117
·
IF 2.175
Wenjing Xia,Nianqing Zhu,Rongjie Hou,Wengui Zhong,Mingqing Chen
The polyurethane prepolymer terminated with a double bond was synthesized using isophorone diisocyanate (IPDI), hydroxyl terminated polybutadiene (HTPB), 1,4-butanediol (BDO), and 2-hydroxyethyl acrylate (HEA). Then, a series of innovative UV-curable polyurethane coatings were prepared by blending ene-terminated polyurethane, fluoroacrylate monomer, and multifunctional thiol crosslinker upon UV exposure. The incorporation of fluoroacrylate monomer and multifunctional thiols into polyurethane coatings significantly enhanced the hydrophobic property, mechanical property, pencil hardness, and glossiness of the polyurethane coatings. This method of preparing UV crosslinkable, hydrophobic polyurethane coatings based on thiol-ene chemistry exhibited numerous advantages over other UV photocuring systems.Keywords:polyurethane;fluorine-containing;UV-crosslinkable
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Huishuang Jiang,Yang Qu,Xianfa Zhang,Rui Gao,Xiaoli Cheng,Shan Gao,Lihua Huo,Zolt́an Major,Yingming Xu
As a poisonous and harmful gas, NO 2 , is not only harmful to the environment, but also detrimental to human health. In this work, ionic liquids (1-hexadecyl-3-methylimidazolium chloride [C 16 Mim] Cl) were selected as dopants to prepare flower-like Cl uniform doped In 2 O 3 nanomaterials. The material exhibits excellent sensing performance to NO 2 under UV light because of Cl uniform doped. Compared with the experiment in dark conditions, the response value of the sensor to 5 ppm NO 2 under UV light is approximately two times higher (S = 425.9) and presents a faster recovery rate (69 s). Chlorine doping shifts the valence band of the material upwards, facilitating the photogenerated electron leap under UV illumination. Moreover, the in-situ DRIFT under UV light were employed to verify the interaction between the materials and NO 2 gas in N 2 , air and O 2 atmospheres respectively. It was found that the presence of oxygen in the environment affects the adsorption of NO 2 on the surface of the Cl doped In 2 O 3 material. This work is of great significance to the sensing mechanism investigation of photo-activated NO 2 gas sensors.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Yu-Jia Nong,Qian-Yuan Wu,Yun-Peng Wu,Ju-Won Lee,Min-Yong Lee,Wen-Long Wang
The KrCl-excimer lamp, emitting far-UVC light at 222 nm (UV222), offers a promising alternative to conventional UVC light at 254 nm (UV254) for the photolysis of organic pollutants and the activation of radical sensitizers. This study was aimed to investigate the efficiencies of UV222 in the treatment of halogenated aromatics, focusing on its performance in degradation, dechlorination and detoxification. Chlorophenols, representative recalcitrant and toxic halogenated aromatics, were used as target pollutants. The pathways of direct photolysis, photooxidation and photoreduction under UV222 illumination were compared. UV222 outperformed UV254 in photolyzing chlorophenols (1.4−34.1 times faster), especially protonated chlorophenols, due to substantially higher UV absorption (17.1−108.0 times) and quantum yields (2.1−3.4 times). The quantum yields of chlorophenols were influenced by the inducive electron-withdrawing effect of Cl-substitutes. Moreover, UV222 improved the dechlorination of chlorophenols to 95 % compared to 60 % by UV254. The introduction of radical sensitizer (e.g., H 2 O 2 , nitrate, and sulfite) reduced 4-chlorophenol photolysis by competing for UV222 absorption, though the sensitizers partially increased radical oxidation via generating • OH or e aq − . UV222 photolysis of 4-chlorophenol increased the toxicity by 88.6 times through forming toxic intermediates (e.g., hydroquinone and resorcinol). Notably, • OH and e aq − (i.e., UV222/H 2 O 2 and UV222/sulfite) increased the dechlorination and • OH (i.e., UV222/H 2 O 2 ) detoxified the mixture solution. Moreover, UV222 photolysis remained effective for 4-chlorophenol removal in real paper-mill wastewater, indicating the potential application of KrCl* lamp UV222.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Functional Materials Letters
·
2023
·
IF 1.3
Pu Qin,Chengyan Zhu,Malik Ashtar,Ming Li,Yuan Liu,Mingming Chen,Dawei Cao,Ying Yang
ZnO is one of the most popular materials in UV photodetectors, but its low switching and long attenuation time seriously hinder its practical application. In this work, the performance of PZT/ZnO planar photodetectors is optimized by using the ferroelectric polarization of PZT thin films. The results show that the residual polarization field of PZT affects the electron arrangement in ZnO film, making ZnO in a depleted state, reducing the dark current of resulted photodetectors, and influencing the carrier life. By inhibiting recombination, the photocurrent is increased, and the switching ratio of the ZnO photodetector is increased by 5 times, and more importantly, the optical responsivity increases by 7 times to 1.015 A/W. This work provides a simple and feasible method for ferroelectric polarization to control the performance of two-dimensional material photodetectors.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Shanshan Su,Chengjin Cao,Yaping Zhao,Dionysios D. Dionysiou
Roxarsone (ROX) is extensively used as a feed additive which tends to leave toxic inorganic arsenic (As) in the natural environment. A composite of reduced graphene oxide and carbon nanotubes was impregnated with goethite designated as α-FeOOH@GCA and tested as an integrated catalyst and adsorbent for ROX decontamination. Nearly 100% of the ROX was transformed in α-FeOOH@GCA activating persulfate (PS) under UV 365 irradiation system at relatively low dosage of the α-FeOOH@GCA catalyst (250 mg L −1 ) in 120 min. The As(V) released in the ROX oxidation was simultaneously adsorbed onto the surface of the α-FeOOH@GCA. A possible ROX transformation pathway is proposed. The As(V) adsorbed on catalyst was recovered and used to form an efficient Ag 3 AsO 4 photocatalyst. This work further extends the oxidation-adsorption technology in solving organoarsenical contamination without producing secondary pollution.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2022
·
IF 3.754
Jian Lu,Hui Lin,Ruijin Hong,Dawei Zhang
By the solid phase reaction method, pure KNN and KNN with different proportions halloysite nanotubes (HNTs) were prepared to study the photocatalytic hydrogen evolution performance under the UV light irradiation. The band gaps of KNN with HNTs are narrower than that of pure KNN. The absorbance of KNN in the ultraviolet region is significantly enhanced by the incorporation of HNTs, where the absorbance in the 200-300 nm region increased about 2 times. Compared with KNN, the conduction band edge of KNN-5wt%HNTs reduced from −1.13 eV to −1.18 eV, showing stronger reducing ability. The H 2 production rate of KNN with HNTs is much higher than that of the raw KNN without HNTs. The best H 2 production rate of KNN-5wt%HNTs is 31.28 μmol•g −1 •h −1 , approximate 4.48 times as high as the rate of pure KNN (6.98 μmol•g −1 •h −1 ), suggesting appropriate addition of HNTs can efficiently improve the H 2 production efficiency.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）