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Effects of humic acid fractions with different polarities on photodegradation of 2,4-D in aqueous environments

YU Chunyan, QUAN Xie, OU Xiaoxia, CHEN Shuo

《环境科学与工程前沿(英文)》 2008年 第2卷 第3期   页码 291-296 doi: 10.1007/s11783-008-0049-1

摘要: Four fractions (A, B, C, and D) of humic acids (HAs) were separated based on the polarity from weak to strong. UV-vis absorption and Fourier transform infrared spectroscopy (FTIR) analysis show that the fractions C and D possessed more aromatic C=C content. The influences of HAs and their fractions on the photolysis were investigated by the photodegradation of 2,4-D solutions under simulated solar light irradiation. The degradation rate of 2,4-D was found to decrease in the presence of bulk HAs or their fractions especially at high HAs concentration. The fractions of strong polarity C and D retarded the degradation rate more than the fractions of weak polarity A and B. This could be attributed to the different absorption intensity of the four HAs fractions in the order of D ≥ C > A > B, and the stronger ?-? electron donor-acceptor interactions between the strong polar fractions and 2,4-D.

关键词: polarity     photodegradation     different absorption     UV-vis absorption     FTIR    

Effect of natural aquatic humic substances on the photodegradation of bisphenol A

ZHAN Manjun, YANG Xi, KONG Lingren, YANG Hongshen

《环境科学与工程前沿(英文)》 2007年 第1卷 第3期   页码 311-315 doi: 10.1007/s11783-007-0052-y

摘要: The photochemical degradation of bisphenol A (BPA) was studied in the presence of natural humic sub stances from different origins under simulated solar irradiation. BPA underwent insignificant direct photolysis in neutral water, but rapid photosensitized degradation in four humic substances solutions via pseudo-first-order reaction occurred. The photodegradation rate of BPA was insensitive to the different initial BPA concentrations and was inhibited in aerated solution compared with the deoxygenated medium. The reactive oxygen species (ROS) such as ?·OH and O produced from excitation of humic substances under irradiation was determined from the quenching kinetic experiment using molecular probe. The five main intermediate photoproducts of BPA in Nordic lake fulvic acid (NOFA) were tentatively identified using gas chromatography/mass spectrometer (GC/MS). Based on the identification of ROS and the analysis of photoproduct formation, the possible phototransformation pathways of BPA were proposed, involving the direct photolysis due to the energy transfer from the triplet state humic substance (HS) to BPA molecules and hydroxyl radical addition and oxidation as well.

关键词: irradiation     photoproduct     deoxygenated     possible phototransformation     bisphenol    

Novel Ag-AgBr decorated composite membrane for dye rejection and photodegradation under visible light

Yixing Wang, Liheng Dai, Kai Qu, Lu Qin, Linzhou Zhuang, Hu Yang, Zhi Xu

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 892-901 doi: 10.1007/s11705-020-2011-0

摘要: Photocatalytic membranes have received increasing attention due to their excellent separation and photodegradation of organic contaminants in wastewater. Herein, we bound Ag-AgBr nanoparticles onto a synthesized polyacrylonitrile-ethanolamine (PAN-ETA) membrane with the aid of a chitosan (CS)-TiO layer via vacuum filtration and partial reduction. The introduction of the CS-TiO layer improved surface hydrophilicity and provided attachment sites for the Ag-AgBr nanoparticles. The PAN-ETA/CS-TiO /Ag-AgBr photocatalytic membranes showed a relatively high water permeation flux (~ 47 L·m ·h ·bar ) and dyes rejection (methyl orange: 88.22%; congo red: 95%; methyl blue: 97.41%; rose bengal: 99.98%). Additionally, the composite membranes exhibited potential long-term stability for dye/salt separation (dye rejection: ~97%; salt rejection: ~6.5%). Moreover, the methylene blue and rhodamine B solutions (20 mL, 10 mg·L ) were degraded approximately 90.75% and 96.81% in batch mode via the synthesized photocatalytic membranes under visible light irradiation for 30 min. This study provides a feasible method for the combination of polymeric membranes and inorganic catalytic materials.

关键词: Ag-AgBr     dye rejection     photodegradation     visible light    

TiO@palygorskite composite for the efficient remediation of oil spills via a dispersion-photodegradation

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1365-3

摘要:

• A novel and multi-functional clay-based oil spill remediation system was constructed.

关键词: Palygorskite     TiO2     Pickering emulsion     Oil spill     Dispersion     Photodegradation    

Factors influencing the photodegradation of

Bingbing XU, Zhonglin CHEN, Fei QI, Jimin SHEN, Fengchang WU

《环境科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 91-97 doi: 10.1007/S11783-009-0013-8

摘要: In order to provide basic data for practical application,photodegradation experiment of -nitrosodimethylamine (NDMA) in aqueous solution was carried out with a low-pressure Hg lamp. Effects of the initial concentration of NDMA, solution pH, dissolved oxygen, and the presence of humic acid on NDMA photodegradation were investigated. NDMA at various initial concentrations selected in this study was almost completely photodegraded by UV irradiation within 20 min, except that at 1.07 mmol/L, NDMA could be photodegraded almost completely in the acidic and neutral solutions, while the removal efficiency decreased remarkably in the alkaline solution. Dissolved oxygen enhanced the NDMA photodegradation, and the presence of humic acid inhibited the degradation of NDMA. Depending on the initial concentration of NDMA, NDMA photodegradation by UV obeyed the pseudo-first-order kinetics. Dimethylamine, nitrite, and nitrate were detected as the photodegradation products of NDMA. O was found to be the reactive oxygen species present in the NDMA photodegradation process by UV, based on the inhibiting experiments using tert-butanol and sodium azide.

关键词: N-nitrosodimethylamine (NDMA)     ultraviolet irradiation     degradation kinetic     dimethylamine     photodegradation product    

Complexation of iron by salicylic acid and its effect on atrazine photodegradation in aqueous solution

Xiaoxia OU, Chong WANG, Fengjie ZHANG, Yan MA, He LIU, Xie QUAN,

《环境科学与工程前沿(英文)》 2010年 第4卷 第2期   页码 157-163 doi: 10.1007/s11783-010-0018-3

摘要: The photodegradation of atrazine and the photochemical formation of Fe(II) and HO in aqueous solutions containing salicylic acid and Fe(III) were studied under simulated sunlight irradiation. Atrazine photolysis followed first-order reaction kinetics, and the rate constant () corresponding to the solution of Fe(III)-salicylic acid complex (Fe(III)-SA) was only 0.0153 h, roughly one eighth of the observed in the Fe(III) alone solution (0.115 h). Compared with Fe(III) solution, the presence of€ salicylic€ acid€ significantly€ enhanced€ the€ formation€ of Fe(II) but greatly decreased HO generation, and their subsequent product, hydroxyl radical (OH), was much less, accounting for the low rate of atrazine photodegradation in Fe(III)-SA solution. The interaction of Fe(III) with salicylic acid was analyzed using Fourier-transform infrared (FTIR) spectroscopy and UV-visible absorption, indicating that Fe(III)-salicylic acid complex could be formed by ligand exchange between the hydrogen ions in salicylic acid and Fe(III) ions.

关键词: salicylic acid     iron     atrazine     photodegradation    

Efficient photodegradation of phenol assisted by persulfate under visible light irradiation via a nitrogen-doped

Yan Cui, Zequan Zeng, Jianfeng Zheng, Zhanggen Huang, Jieyang Yang

《化学科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 1125-1133 doi: 10.1007/s11705-020-2012-z

摘要: To realize the utilization of visible light and improve the photocatalytic efficiency of organic pollutant degradation in wastewater, a nitrogen-doped titanium-carbon composite (N-TiO /AC) prepared by sol-gel methods was applied in the photodegradation of phenol assisted by persulfate under visible light irradiation (named N-TiO /AC/PS/VIS). The results show that a synergistic effect exists between visible-light photocatalysis and persulfate activation. Compared with TiO /PS/VIS, the phenol degradation rate was found to be observably improved by 65% in the N-TiO /AC/PS/VIS system. This significant increase in degradation rate was mainly attributed to the following two factors: 1) The N and C doping can change the crystal structure of TiO , which extends the TiO absorption wavelength range to the visible light region. 2) As an electron acceptor, PS can not only prevent electrons and holes from recombining with each other but can also generate strong oxidizing radicals such as ∙SO and ∙OH to accelerate the reaction dynamics. The process of phenol degradation was found to be consistent with the Langmuir pseudo-first-order kinetic model with an apparent rate constant of 1.73 min . The N-TiO /AC/PS/VIS process was proven to be a facile method for pollutant degradation with high pH adaptability, excellent visible-light utilization and good application prospects.

关键词: N-TiO2/AC     visible light     photocatalysis     persulfate activation     phenol    

Photodegradation of chromophoric dissolved organic matters in the water of Lake Dianchi, China

Yuan ZHANG,Chunming HU,Tao YU

《环境科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 575-582 doi: 10.1007/s11783-014-0664-y

摘要: Water samples were taken from Lake Dianchi, on the Yungui Plateau of southwest China, and experiments were conducted to simulate the photochemical degradation characteristic of chromophoric dissolved organic matter (CDOM) in the lake water. Three groups of experiments under different light conditions: ultraviolet (UV) light, visible light, and dark, were done and variations of fluorescence properties, UV absorbance, and dissolved organic carbon (DOC) concentrations during the experiments were analyzed to study the photodegradation process of CDOM with time. The result showed that light irradiation led to significant photochemical degradation of CDOM, resulting in changes in florescent properties, absorbance losses, decreases in aromaticity and average molecular weight, as well as decline in DOC concentration in the water. It was also observed that UV irradiation had greater effect than visible light did. However, various fluorophores had different sensitivities to the same irradiation condition, that is, protein-like fluorophore at the low excitation wavelengths is more sensitive to UV irradiation than the other fluorophores, and is more readily to undergo photo-degradation. In addition, visible light irradiation did not have significant impact on DOC in the water, with DOC concentration decrease by 5.57% –59.9% during the experiment time. These results may provide new knowledge on the environment behavior of CDOM in the water of Lake Dianchi.

关键词: chromophoric dissolved organic matter     photodegradation     ultraviolet radiation     dissolved organic carbon    

organic matter from wastewater treatment plants and their mediation effect on 17α-ethinylestradiol photodegradation

《环境科学与工程前沿(英文)》 2023年 第17卷 第6期 doi: 10.1007/s11783-023-1669-1

摘要:

● EE2 photodegradation behavior in the presence of four WWTPs’ DOM was explored.

关键词: Photosensitivity sources     17α-ethinylestradiol     Photodegradation     Dissolved organic matter     Wastewater treatment plants    

Durable and recyclable BiOBr/silk fibroin-cellulose acetate composite film for efficient photodegradation

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1765-1775 doi: 10.1007/s11705-023-2323-y

摘要: A stable and recyclable of BiOBr/silk fibroin-cellulose acetate composite film was prepared by blending-wet phase transformation and in situ precipitate technology. The cellulose acetate film modified by silk fibroin formed a finger-shaped porous structure, which provided a large space for the uniform growth of BiOBr nanosheets and facilitated the shuttle flow of dyes in film. The morphology, phase structure, and optical properties of the composite films were characterized using various techniques, and their photocatalytic performance for dye wastewater was evaluated under visible light irradiation. Results showed that the BiOBr/SF-CA composite film exhibited efficient photocatalytic activity with 99.9% of rhodamine B degradation rate. Moreover, the composite film maintained high catalytic stability because Bi as the active species deposited on the film showed almost no loss. Finally, the possible photocatalytic mechanisms in the BiOBr/SF-CA composite film were speculated through radical-trapping experiments and electron spin resonance testing.

关键词: BiOBr nanosheet     cellulose acetate     silk fibroin     photocatalytic degradation     dye wastewater    

Predictive models on photolysis and photoinduced toxicity of persistent organic chemicals

Qing ZHANG

《环境科学与工程前沿(英文)》 2013年 第7卷 第6期   页码 803-814 doi: 10.1007/s11783-013-0547-7

摘要: Photodegradation is a major abiotic transformation pathway of toxic chemicals in the environment, which in some cases might lead to photoinduced toxicities. The data on photodegradation kinetics and photoinduced toxicities of organic chemicals are essential for their risk assessment. However, the relevant data are only available for a limited number of chemicals, due to the difficulty and high cost of experimental determination. Quantitative structure-activity relationship (QSAR) models that relate photodegradation kinetics or photoinduced toxicity of organic chemicals with their physicochemical properties or molecular structural descriptors may enable simple and fast estimation of their photochemical behaviors. This paper reviews the QSAR models on photodegradation quantum yields and rate constants for toxic organic chemicals in different media including liquid phase, gaseous phase, surfaces of plant leaves, and QSAR models on photoinduced toxicity of organic chemicals to plants, bacteria, and aquatic invertebrates. Further prospects for QSAR model development on photodegradation kinetics and photoinduced toxicity of refractory organic chemicals are proposed.

关键词: quantitative structure-activity relationship (QSAR) models     photodegradation     persistent organic pollutants     environmental media     mechanisms    

Improving hole transfer of boron nitride quantum dots modified PDI for efficient photodegradation

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1718-1727 doi: 10.1007/s11705-023-2319-7

摘要: In recent years, organic photocatalyst under visible-light absorption has shown significant potential for solving environmental problems. However, it is still a great challenge for constructing a highly active organic photocatalyst due to the low separation efficiency of photogenerated carriers. Herein, an effective and robust photocatalyst perylene-3,4,9,10-tetracarboxylic diamide/boron nitride quantum dots (PDI/BNQDs), consisting of self-assemble PDI with π–π stacking structure and BNQDs, has been constructed and researched under visible light irradiation. The PDI/BNQDs composite gradually increases organic pollutant photodegradation with the loading amount of BNQDs. With 10 mL of BNQDs solution added (PDI/BNQDs-10), the organic pollutant photodegradation performance reaches a maximum, about 6.16 times higher with methylene blue and 1.68 times higher with ciprofloxacin than that of pure PDI supramolecular. The enhancement is attributed to improved separation of photogenerated carriers from self-assembled PDI by BNQDs due to their preeminent ability to extract holes. This work is significant for the supplement of PDI supramolecular composite materials. We believe that this photocatalytic design is capable of expanding organic semiconductors’ potential for their applications in photocatalysis.

关键词: PDI     boron nitride     quantum dots     photocatalysis     hole transfer    

Tuning nitrogen defects and doping sulfur in carbon nitride for enhanced visible light photocatalytic activity

《化学科学与工程前沿(英文)》 2023年 第17卷 第1期   页码 93-101 doi: 10.1007/s11705-022-2175-x

摘要: Defect construction and heteroatom doping are effective strategies for improving photocatalytic activity of carbon nitride (g-C3N4). In this work, N defects were successfully prepared via cold plasma. High-energy electrons generated by plasma can produce N defects and embed sulfur atoms into g-C3N4. The N defects obviously promoted photocatalytic degradation performance that was 7.5 times higher than that of pure g-C3N4. The concentration of N defects can be tuned by different power and time of plasma. With the increase in N defects, the photocatalytic activity showed a volcanic trend. The g-C3N4 with moderate concentration of N defects exhibited the highest photocatalytic activity. S-doped g-C3N4 exhibited 11.25 times higher photocatalytic activity than pure g-C3N4. It provided extra active sites for photocatalytic reaction and improved stability of N defects. The N vacancy-enriched and S-doped g-C3N4 are beneficial for widening absorption edge and improving the separation efficiency of electron and holes.

关键词: g-C3N4     nitrogen defect     sulfur doping     photodegradation     plasma    

Photolysis and photooxidation of typical gaseous VOCs by UV Irradiation: Removal performance and mechanisms

In-Sun Kang, Jinying Xi, Hong-Ying Hu

《环境科学与工程前沿(英文)》 2018年 第12卷 第3期 doi: 10.1007/s11783-018-1032-0

摘要: Photodegradation by ultraviolet irradiation (UV) is increasingly applied in volatile organic compound (VOC) and odor gas treatments. In this study, 27 typical VOCs, including 11 hydrocarbons and 16 hydrocarbon derivatives, at 150–200 ppm in air and nitrogen gas were treated by a laboratory-scale UV reactor with 185/254 nm irradiation to systematically investigate their removal and conversion by UV irradiation. For the tested 27 VOCs, the VOC removal efficiencies in air were within the range of 13%–97% (with an average of 80%) at a retention time of 53 s, which showed a moderate positive correlation with the molecular weight of the VOCs ( = 0.53). The respective contributions of photolysis and photooxidation to VOC removal were identified for each VOC. According to the CO results, the mineralization rate of the tested VOCs was within the range of 9%–90%, with an average of 41% and were negatively correlated to the molecular weight ( = 0.63). Many of the tested VOCs exhibited high concentration particulate matters in the off-gases with a 3–283 mg/m PM range and a 2–40 mg/m PM range. The carbon balance of each VOC during UV irradiation was analyzed based on the VOC, CO and PM concentrations. Certain organic intermediates and 23–218 ppm ozone were also identified in the off-gases. Although the UV technique exhibited a high VOC removal efficiency, its drawbacks, specifically low mineralization, particulate matters production, and ozone emission, must be considered prior to its application in VOC gas treatments.

关键词: VOCs     UV photodegradation     Particulate matters     Ozone    

Fabrication of titania thin film with composite nanostructure and its ability to photodegrade rhodamine B in water

ZHANG Gaojie, WU Jinming, LIU Shaoguang, YAN Mi

《化学科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 44-48 doi: 10.1007/s11705-008-0001-8

摘要: A titania nanorod film was synthesized by direct oxidation of metallic Ti with hydrogen peroxide solution under a low temperature. Titania nanoparticles were then filled into the gaps among the nanorods through an infiltration sol-gel procedure to form a composite titania film with an ordered nanostructure. X-ray diffraction spectra indicate that the composite film was a mixture of anatase and rutile while the titania film obtained by only using a sol-gel procedure was pure anatase. Field emission scanning electron microscopy observations show that titania nanoparticles were embedded into the titania nanorod film. Photoluminescence spectra suggest the enhanced separation of electron and hole pairs for the obtained composite titania film over the corresponding titania nanorod film. The composite titania film exhibited improved ability to photodegrade rhodamine B in water compared with the titania nanorod film. The apparent photodegradation rate constant, fitting a pseudo-first-order, was 3 times of that obtained by the sol-gel derived titania film at the same weight. The improved photocatalytic activity for the composite titania film could be attributed to the enhanced separation of electron and hole pairs due to the embedding of the titania nanoparticles within the titania nanorods.

关键词: constant     weight     apparent photodegradation     hydrogen     nanorod    

标题 作者 时间 类型 操作

Effects of humic acid fractions with different polarities on photodegradation of 2,4-D in aqueous environments

YU Chunyan, QUAN Xie, OU Xiaoxia, CHEN Shuo

期刊论文

Effect of natural aquatic humic substances on the photodegradation of bisphenol A

ZHAN Manjun, YANG Xi, KONG Lingren, YANG Hongshen

期刊论文

Novel Ag-AgBr decorated composite membrane for dye rejection and photodegradation under visible light

Yixing Wang, Liheng Dai, Kai Qu, Lu Qin, Linzhou Zhuang, Hu Yang, Zhi Xu

期刊论文

TiO@palygorskite composite for the efficient remediation of oil spills via a dispersion-photodegradation

期刊论文

Factors influencing the photodegradation of

Bingbing XU, Zhonglin CHEN, Fei QI, Jimin SHEN, Fengchang WU

期刊论文

Complexation of iron by salicylic acid and its effect on atrazine photodegradation in aqueous solution

Xiaoxia OU, Chong WANG, Fengjie ZHANG, Yan MA, He LIU, Xie QUAN,

期刊论文

Efficient photodegradation of phenol assisted by persulfate under visible light irradiation via a nitrogen-doped

Yan Cui, Zequan Zeng, Jianfeng Zheng, Zhanggen Huang, Jieyang Yang

期刊论文

Photodegradation of chromophoric dissolved organic matters in the water of Lake Dianchi, China

Yuan ZHANG,Chunming HU,Tao YU

期刊论文

organic matter from wastewater treatment plants and their mediation effect on 17α-ethinylestradiol photodegradation

期刊论文

Durable and recyclable BiOBr/silk fibroin-cellulose acetate composite film for efficient photodegradation

期刊论文

Predictive models on photolysis and photoinduced toxicity of persistent organic chemicals

Qing ZHANG

期刊论文

Improving hole transfer of boron nitride quantum dots modified PDI for efficient photodegradation

期刊论文

Tuning nitrogen defects and doping sulfur in carbon nitride for enhanced visible light photocatalytic activity

期刊论文

Photolysis and photooxidation of typical gaseous VOCs by UV Irradiation: Removal performance and mechanisms

In-Sun Kang, Jinying Xi, Hong-Ying Hu

期刊论文

Fabrication of titania thin film with composite nanostructure and its ability to photodegrade rhodamine B in water

ZHANG Gaojie, WU Jinming, LIU Shaoguang, YAN Mi

期刊论文