JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 135
·期 37
·46686
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IF 1.901
Safdar Ali,Farooq Khurum Shehzad,Inamullah Maitlo,Sultan Valiev,Ghulam Muhyodin,Jun Nie
Two types of cryogels were obtained using 2-hydroxyethyl acrylate (HEA) and 2-hydroxyethyl methacrylate (HEMA) by homogeneous mixing with poly(ethylene glycol) diacrylate (PEGDA) as crosslinker at subzero temperature followed by photopolymerization with two different light initiation sources (high-pressure Hg arc lamp and UV-LED).The solution was frozen unidirectionally at −60 °C before polymerization and finally photopolymerized at the same temperature. The cryogels were characterized using photo-DSC, UV–vis and Fourier transform infrared spectroscopy, and scanning electron microscopy techniques. The cryogels cured with an LED light showed a higher polymerization rate and better morphological characteristics than ones cured with a high-pressure Hg arc. The water intake ratio of HEA/PEGDA was higher than HEMA/PEGDA for both curing sources. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46686.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2022
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IF 5.141
Liangchen Long,Yang Yang,Shijie You,Liangliang Wei,Baiyang Chen
Quantifying ultraviolet (UV) photon flux is important for water photolysis practice. However, it is currently challenging to quantify the photon flux of 185 nm vacuum UV (VUV 185 ) emitted by low-pressure mercury lamp (LPML) because of the interference of coexisting 254 nm UV (UV 254 ). Given that formaldehyde (FA) is insensitive to UV 254 within the time scale of interests whereas vulnerable to VUV 185 , this study for the first time evaluated the possibility of using FA as a chemical actinometer to determine the VUV 185 photon flux under varying conditions. Experimental results revealed that the photodegradation of FA followed a pseudo -1 st -order reaction kinetic under VUV 185 irradiation, and the products of initial concentration ( C 0 ) and reaction rate constants (i.e., C 0 × k ) were proportional to the numbers of LPMLs (under C 0 of 50–300 mg/L), suggesting that C 0 × k is an excellent indicator for photon flux determination. Increasing dissolved oxygen concentration from 1.0 to 7.8 mg/L, pH from 4.0 to 10.4, and temperature from 22 to 44 °C all imposed negligible interferences (variation ≤ 10%) on the C 0 × k values, proving that FA is a good actinometer for VUV 185 photon flux detection. Because FA can be measured readily by spectrophotometry method, its use as an actinometer is more convenient than conventional actinometers. Therefore, this study demonstrates that FA is a promising candidate of actinometer for VUV 185 quantification in the copresence of UV 254 .
研究领域:
环境科学
·
水处理工程
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DOI
高影响因子
ENVIRONMENTAL RESEARCH
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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
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水处理技术
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2018
·
IF 6.653
Guoyang Zhang,Shijie Wei,Bingdang Wu,Zhihao Chen,Shujuan Zhang
Nitrous oxide (N2O) is widely used in radiation-chemistry and photochemistry as a scavenger to convert a hydrated electron (eaq–) into a hydroxyl radical (·OH). However, few investigations pay attention to the photochemistry of dissolved N2O itself. The effects of purged N2O on photochemical processes are unclear and neglected. In the present work, the effects of N2O on the hydroxylation of terephthalic acid (TPA) were investigated with both medium-pressure and low-pressure mercury lamps as the light sources. Under short-wavelength UV (200–300 nm) irradiation, N2O accelerated the decay of TPA and the formation of 2-hydroxylterephthalic acid (hTPA). The effective quantum yield of ·OH from the photolysis of dissolved N2O at 254 nm was determined as 1.15–1.63, which was far larger than those of NO3– (0.09) and NO2– (0.046). On the basis of the kinetic analysis in N2 and N2O purged solutions, isotope fractionation with heavy oxygen water, and ·OH scavenging experiments with tert-butyl alcohol, the contribution of the ·OH radicals generated from the photolysis of N2O to the formation of hTPA (61.7%) was determined to be 1 order of magnitude higher than that from the converted eaq– (6.5%). These results demonstrate that using N2O and ·OH probes to quantify photogenerated eaq– in UVC irradiation might lead to false results. The work here is helpful for the proper design of scavenging and probing experiments by the combination of N2O and ·OH probes.
研究领域:
光化学
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辐射化学
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环境科学
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分析化学
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产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Jiaojiao Fan,Yuanzhi Zheng,Yingtian Yang,Le Du,Yujun Wang
Ultraviolet B (UVB) irradiation is of great importance for photochemical synthesis of steroidal intermediates, which could be efficiently provided by neither traditional mercury lamps nor novel light-emitting diodes. Herein, a photochemical microfluidic strategy with enhanced UVB irradiation was developed by the integration of novel photoluminescent composite films, which were readily prepared to shift the emission peak. The UVB emission intensity was increased by approximately 10 times for an 8 W lamp with this flexible and removable film. It allowed a productivity as high as that of a 100 W lamp without using any cooling devices, showing great potential to replace traditional medium-pressure mercury lamps for UVB-irradiated synthesis. In addition, a calculation method was developed to assess the effect of specific wavelengths based on the photon flux and photonic efficiency, which could provide theoretical guidance for photochemical microfluidic processes to refine the emission ranges.
研究领域:
化学工程
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材料科学
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光化学
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产品关联
DOI
高影响因子
Chemical Engineering and Processing-Process Intensification
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2023
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IF 4.3
Yu Zhong,Kama Huang,Nanya Zhong,Yijun Wang,Wenqi Chen
The traditional cathode low-pressure Hg lamp is the most mainstream UV light source in degrading organic wastewater but with significant limitations of short lifetime, environmental hazard and poor degradation efficiency. Here, we evaluate a self-designed microwave-driven ZnI 2 deep-UV lamp on degrading Rhodamine B (RhB), methylene blue (MB), and p-nitrophenol (PNP). An electrodeless Hg lamp was used as control. First we investigated the emission wavelength, spatial radiation distribution, the effect of power on radiation intensity, and relative permittivity of ZnI 2 lamp. Then the degradation rate, kinetics and energy yield on degrading RhB, MB and PNP as well as the cost were studied. ZnI 2 lamp showed shorter wavelengths, approaching UVC radiation intensity, approaching attenuation factor and higher microwave coupling capability to Hg lamp. After treatment with ZnI 2 lamp for 10, 6 and 15 min, 5 mg/L of RhB, MB and PNP can reach 100% removal rates. Moreover, higher degradation rate and kinetic constants of ZnI 2 lamp for 3 compounds than the Hg lamp in this paper and in the literature were achieved. With the assistance of microwave and properties of environmental-friendly and low cost, ZnI 2 lamp provides a new alternative to traditional Hg lamp and wastewater photochemical treatment method.
研究领域:
环境科学
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光化学技术
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产品关联
DOI
高影响因子
ACS Applied Energy Materials
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2023
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IF 6.4
Jinni Shen,Xu Liu,Yuhua Zhong,Chengwei Qiu,Huihui Xu,Hongsheng He,Haifeng Li,Jianhan Lin,Zizhong Zhang,Xuxu Wang
Solar light-driven overall water splitting for hydrogen production is an ideal solution to climate warming and energy shortage issues. Obtaining a highly efficient and stable photocatalyst remains a major challenge at present. Herein, NixP/γ-Ga2O3 nanosheets, which were synthesized from NiCl2, NaH2PO2, and home-made γ-Ga2O3 nanosheets by the photodeposition method under 254 UV irradiation for 30 min, are found as a highly active and durable photocatalyst for pure water splitting into H2 and O2 without a sacrificial reagent. The H2 production rate is as high as 5.5 mmol·g–1·h–1 under 125 W high-pressure mercury lamp irradiation, which is 3.4 and 2.5 times higher than that on the pristine γ-Ga2O3 nanosheets and Pt/γ-Ga2O3 nanosheets, respectively, and is 2.0 times higher than that on the 0.5 wt % Ni2P/γ-Ga2O3 reported previously. However, the O2 evolution rate is much less than the H2 evolution rate in the initial reaction stage. On prolonging the irradiation time, H2 evolution declines, while O2 evolution increases until it reaches its stoichiometric value corresponding to H2. The reason for the photocatalytic behavior of NixP/γ-Ga2O3 is studied and the corresponding mechanism is suggested. The absent or low oxygen evolution in the initial reaction stage is because the dioxygen generated from water oxidation by the photogenerated holes is wholly or partially captured by the surface oxygen vacancies to form the surface peroxide bonds (−O–O−). Once the oxygen vacancies are eliminated by the photogenerated O2, the overall water splitting reaction would reach the steady state. Thereafter, H2 production decreases from 5.5 to 2.0 mmol·g–1·h–1, but the O2 evolution gradually approaches the corresponding stoichiometric value, especially for the photocatalyst treated with H2O2 for 24 h.
研究领域:
材料科学
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催化
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可再生能源
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光化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2024
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IF 8.2
Zhi Wang,Mingyang Li,Wei Cao,Zhenhua Liu,Deyang Kong,Wei Jiang
Perfluorooctanoic acid (PFOA) is potentially toxic and exceptionally stable attributed to its robust C F bond, which is hard to be removed by UV/TiO 2 systems. In this research, bismuth nanoparticle (Bi NP) modified titanium oxides (Bi/TiO 2 ) were synthesized by a simple photochemical deposition-calcination method and were applied as photocatalysts for the first time to degrade PFOA. The removal rate of 50 mg/L PFOA reached 99.3 % with 58.6 % defluorination rate after 30 min of irradiation via a mercury lamp. Bi/TiO 2 exhibited superior performance in PFOA degradation compared to commercial photocatalysts (TiO 2 , Ga 2 O 3 , Bi 2 O 3 and In 2 O 3 ). In addition, Bi/TiO 2 showed high degradation activity under actual sunlight, achieved 100 % removal rate and 59.3 % defluorination rate within 2 h. Bi NPs increase the light trapping ability of Bi/TiO 2 and promote the separation of photogenerated electron-hole pairs via local surface plasmon resonance (LSPR) effect, which results in more photogenerated holes (h + ) and hydroxyl radicals ( OH). Combined with DFT calculations and intermediate detections, the degradation reaction is initiated from the oxidation of the PFOA carboxyl group via h + , followed by the loss of the CF 2 unit step by step with the participation of OH. This work presents a novel approach for the practical implementation of TiO 2 -based photocatalysts to achieve highly efficient photocatalytic degradation of perfluorocarboxylic acids (PFCAs).
研究领域:
环境科学
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材料科学
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化学
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产品关联
DOI
PubMed
高影响因子
Journal of Analytical Methods in Chemistry
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2017
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IF 1.801
Longli Lin,Qijun Wu,Xun Gong,Yu Zhang
To solve the problem of separation and recovery of photocatalyst in water, the modification of TiO2 was studied as well as its immobilization and photocatalytic properties. To improve surface properties, TiO2 nanotubes were synthesized by a hydrothermal method and silylated by silane coupling agents to introduce a certain functional group. Supported on polyurethane (PU) membrane, TiO2 nanotubes were prepared to produce immobilized PU/TiO2. Catalysts were characterized and identified by means of Fourier-transform infrared spectroscopy (FTIR), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy (SEM). Results showed that silylated TiO2 nanotubes were well grafted on the surface of the activated PU membrane. With a 300 W high pressure mercury lamp as light source, the photocatalytic activity and stability of immobilized PU/TiO2 were investigated with degrading methyl orange. It was showed that the target is degraded by immobilized PU/TiO2 with high activation and the catalytic performance is stable for a long time if catalyst is washed with ethanol.
研究领域:
材料科学
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环境工程
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化学工程
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纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）