CHEMICAL ENGINEERING JOURNAL
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2021
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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
SCIENCE OF THE TOTAL ENVIRONMENT
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2018
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IF 4.61
Guo-Qiang Li,Zheng-Yang Huo,Qian-Yuan Wu,Yun Lu,Hong-Ying Hu
An ultraviolet (UV)-based advanced oxidation process (AOP) for disinfecting water is introduced in this paper. This study aimed to evaluate the potential of UV light-emitting diodes (UV-LEDs)/chlorine AOP (UV/Cl 2 ) for Bacillus subtilis spore inactivation. Chlorine was combined with 265 and 280 nm LEDs (UV 265 /Cl 2 , UV 280 /Cl 2 ) and investigated. The addition of 4.0 mg/L of free chlorine at pH 7.0 in the presence of 125 mJ/cm 2 of UV irradiation resulted in an additional 1.8-log reduction in UV 265 /Cl 2 and 1.5-log reduction in UV 280 /Cl 2 . There was no observed enhancement in spore inactivation with the addition of a radical scavenger, t-BuOH, which indicated the role of • OH in the synergistic effect. To quantitatively evaluate the synergism, the primary treatment with UV/Cl 2 was followed by further UV or Cl 2 treatment. After UV/Cl 2 pretreatment at different pH levels, the 265 and 280 nm LEDs treatment enhanced an approximate 0.4–0.5-log reduction compared to UV only, and Cl 2 treatment enhanced an approximate 0.7–1.1-log reduction compared to Cl 2 only. In addition, at pH 7.0, in UV 265 /Cl 2 -Cl 2 and UV 280 /Cl 2 -Cl 2 , the inactivation rate constant k increased by approximately 2 and 1.5 times, respectively. The CT for the lag phases ( CT lag ) reduced to approximately 67 and 58%, respectively. Similar results were obtained at pH 7.5 and 8.0, and in the secondary effluent. The synergistic effect on spore inactivation suggested that the pathogen inactivation efficiency of sequential UV and chlorine disinfection processes, which are commonly applied, can be significantly enhanced by adding chlorine prior to UV treatment .
研究领域:
微生物学
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环境科学
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水处理技术
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
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2019
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IF 7.913
Xiang-Yun Zou,Yi-Li Lin,Bin Xu,Tian-Yang Zhang,Chen-Yan Hu,Tong-Cheng Cao,Wen-Hai Chu,Yang Pan,Nai-Yun Gao
Ultraviolet light-emitting diodes (UV-LEDs) are promising alternatives to conventional low-pressure UV (LPUV) lamps, mainly because they contain no toxic mercury and have a potential for less energy consumption and longer lifetime. In this study, UV sources including UV-LEDs (265, 275 and 285 nm) and LPUV (254 nm) were compared in UV/chlorine degradation of an organic contaminant , ronidazole (RNZ). UV-LED/chlorine performed better than LPUV/chlorine at neutral and alkaline pH values for RNZ degradation considering the fluence-based rate constant. However, the wall plug efficiencies of UV-LEDs are relatively low at present and must reach about 20–25% to achieve the same electrical energy per order as the LPUV in UV/chlorine degradation of RNZ at pH 7.5 and 9. Neither the contribution of radical (HO· or Cl·) nor the quantum yield of chlorine could explain the different RNZ degradation rate by UV/chlorine at different wavelengths and pH values, while the chlorine photolysis rate should be the key factor for these phenomena. The effects of common co-existing substances in real water (chloride, bicarbonate and natural organic matter) on UV/chlorine degradation of RNZ were similar at different UV wavelengths. Opposite to other oxidants or reductants, the molar absorption coefficient of chlorine increases when the UV wavelength increases from 254 to 285 nm at neutral and alkaline pH, which makes UV-LED/chlorine one of the best choices for UV-LED-based advanced oxidation/reduction processes.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2018
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IF 6.735
Ze-Chen Gao,Yi-Li Lin,Bin Xu,Ying Xia,Chen-Yan Hu,Tong-Cheng Cao,Xiang-Yun Zou,Nai-Yun Gao
This study revealed the iopamidol degradation performance and the synergistic effect of dual-wavelength ultraviolet light-emitting diodes (UV-LEDs). It was found that the dual-wavelength irradiation (265 and 280 nm) can promote iopamidol degradation during both UV-LED alone and UV-LED/chlorine processes ( p < 0.05). The effects of key experimental parameters including pH, chlorine dosage and water matrix during UV-LED/chlorine process were evaluated. Peak degradation rate was observed at pH 7.0 due to the combined effects of the quantum yield of aquatic chlorine photolysis (Φ chlorine ) and absorptivity of chlorine. The destruction pathways of iopamidol in the UV-LED/chlorine process were proposed by Ultra Performance Liquid Chromatography-Electrospray Ionization-mass spectrometry. Additionally, an opposite trend of iodinated trihalomethane (I-THM) formation during subsequent chlorination between Milli-Q and real waters with prolonging irradiation time was observed, while other detected disinfection by-product (DBP) formation showed the same variation in Milli-Q and real waters. The UV-LED/chlorine treatment using dual-wavelength can enhance iopamidol degradation significantly, but it also promoted I-THM formation in real water, indicating the need for evaluating DBPs before the application of UV-LED/chlorine process in drinking water treatment.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
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2020
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IF 4.006
Liumin Fan,Xiao Liu,Xiuping Dong,Shanshan Dong,Qisen Xiang,Yanhong Bai
Ultraviolet light-emitting diodes (UV-LEDs) have become widespread for decontaminating the surfaces of food products and their packaging as a safer alternative to traditional mercury-vapor based UV lamps. This study aimed to investigate the effect of UVC- LEDs (275 nm) on the inactivation of foodborne pathogens and quality attributes of raw tuna fillets. Raw tuna fillets inoculated with cocktails of Salmonella Typhimurium, Listeria monocytogenes , and Escherichia coli O157:H7 were exposed to UVC-LEDs at 500-4000 mJ/cm 2 . UVC-LED treatments of single-layer tuna fillets at a dose of 4000 mJ/cm 2 resulted in 1.31-, 1.86-, and 1.77- log reduction of S . Typhimurium, L . monocytogenes , and E . coli O157:H7, respectively. The pH value, water-holding capacity, metmyoglobin, texture, and color characteristics of tuna fillets were not significantly ( p > 0.05) changed following the UVC-LED treatment at radiation doses up to 4000 mJ/cm 2 . Nonetheless, the UVC-LED irradiation led to increased levels of lipid oxidation in tuna fillets. Overall, the present study demonstrates that UVC-LEDs are a promising technology to reduce microbial flora and maintain the physicochemical properties of fish products.
研究领域:
食品科学
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微生物学
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DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
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2015
·Vol. 25
·期 18
·2754-2762
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IF 11.805
Yujing Zuo,Jinfeng Cao,Shengyu Feng
The increasing pursuit of biocontained elastic materials led the investigation of the potential use of the monoterpene limonene in film synthesis via thiol–ene reaction. Poly[(mercaptopropyl)methylsiloxane] (PMMS) is first synthesized. By controlling the molar ratio of PMMS and functional monomers, such as polyethylene glycol allyl methyl ether or rhodamine-B, PMMS is partially functionalized while leaving spare mercapto groups that could be further used as cross-linking sites. On the basis of the functionalized PMMS, novel transparent silicone luminescent films with hydrophilic tunable properties are prepared by natural-sunlight-triggered thiol–ene “click” chemistry by using d -limonene as a cross-linker. Their structures and properties are thoroughly characterized. Transparent luminescent films are coated on commercially available UV-light emitting diode (LED) cell from solution medium followed by an in situ cross-linking step; a colorful LED cell is obtained through this facile and efficient method. The UV-LED coated by films show very intense photoluminescence under normal visible light or the light is on, and has very high coloric purity.
研究领域:
材料科学
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化学工程
✓ 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）