CHEMOSPHERE
·
2019
·
IF 5.108
Junqin Liu,Pingxiao Wu,Shuaishuai Li,Meiqing Chen,Wentin Cai,Dinghui Zou,Nengwu Zhu,Zhi Dang
A high removal rate (>99.7%) of combined arsenite (As(III)) and Cd (Cd(II)) in low concentration (1000 μg/L) from contaminated water was achieved by a calcined MgZnFe-CO 3 layered double hydroxide (CMZF) adsorbent. Batch control studies and a series of spectroscopy detection technologies were employed to investigate the removal mechanism and interactions between As(III) and Cd(II) on the interface of water/CMZF. Synergistic adsorption and photooxidation occurred based on the systematical kinetic and isotherm studies. The enhanced removal of As(III) was achieved by the photooxidation, formation of ternary As(III) Cd(II) surface complexes and enhanced hydrogen bond . Meanwhile, oxidative formed negative charged As(V) could reduce the electrostatic repulsion force between Cd(II) cations and play a role as anion bridging, consequently resulted in a stronger attraction between CMZF and Cd(II). Combined with the verdicts of relevant characterizations such as XRD, XPS and EPR, it was assumed that the deep co-removal mechanism could be attributed to the coupling of various processes including intercalation, complexation, photooxidation of As(III) and precipitation of CdCO 3 . Moreover, the successful removal of As(III) and Cd(II) from real water matrix qualified the CMZF a potentially attractive adsorbent for both As(III) and Cd(II) deep treatment in practical engineering.
研究领域:
环境科学
·
材料科学
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2012
·Vol. 20
·期 1
·31-38
·
IF 2.651
Wang Yajie,Xu Jing,Zhao Yan,Zhang Lin,Xiao Mei,Wu Feng
Iron and arsenic have been found to coexist in a water environment and the fate of arsenite in the aquatic system is influenced by iron. Goethite is a form of iron hydroxide, which is commonly found in sediments. In previous studies, we have used iron complexes to degrade organic pollutants. Results have shown that some organic pollutants could be totally degraded by iron complexes and our work indicated that iron might cause conversion of arsenic when irradiated. This work attempts to investigate the conversion of arsenite [As(III)] using natural goethite, as the iron source, to quantify the effect of various factors on photooxidation. We also consider the possible mechanism for photooxidation of As(III) using a suspension of natural goethite. The As(III) concentration variation under illumination was compared with the one in the dark to quantify the contribution of light to As(III) oxidation to As(V) in goethite suspended solution. The experiments under N 2 and air atmosphere confirmed the participation of dissolved oxygen. The photooxidation efficiency of As(III) under different conditions was compared to determine the effect of different environmental factors such as pH value, goethite concentration, and humic acid concentration on the photooxidation reaction. In the solution containing 100 μg L −1 arsenite and 0.1 g L −1 suspended goethite at pH 3.0, nearly 80 % of As(III) was photooxidized after irradiation by a 250-W metal halogen lamp ( λ ≥ 313 nm) after 6 h. The effects of initial pH and goethite concentration and humic acid concentration were all examined. The results show that the greatest efficiency of photooxidation of As(III) was at pH 3.0. The extent of photooxidation decreased with increasing goethite concentration and fell sharply in the presence of humic acid under the conditions in this work. Although about 80 % of As(III) was photooxidized after irradiation by a 250-W halogen lamp at pH 3.0 in the presence of goethite suspension, photooxidation was also affected by factors such as pH, concentration of goethite, and presence of humic acid. The scavenger experiments showed that the HO• radical and photogenerated hole are the predominant oxidants in this system responsible for 87.1 % oxidation of As(III), while HO
• 2
/O
•− 2
is responsible for 12.9 % oxidation of As(III).
研究领域:
环境科学
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化学
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DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2021
·
IF 3.196
Yajie Wang,Xianhe Gong,Xin Dong,Yunjie Wu
In this work, arsenite (As(III)) removal in a goethite/oxalate suspension under UVA-irradiation (λ max = 365 nm) was explored under different conditions (initial pH, oxalate concentration, goethite dosage, and phosphate). SEM, EDS, FTIR, XRD and XPS were used to investigate the morphology, composition, functional groups, structure, and surface properites of goethite. The greatest efficiency of As(III) removal was 95.52% at pH 3.0, 100.0 µg·L –1 As(III), 0.05 g·L –1 goethite, and 0.5 mmol·L –1 oxalate. The removal of As(III) in the goethite/oxalate system was strongly pH-dependent. An increase in pH was accompanied by a reduction in photo-oxidation efficiency and an increase in adsorption efficiency. Addition of appropriate amounts of oxalate can enhance As(III) removal at pH 3.0 by promoting the photo-dissolution of iron oxide. However, the addition of oxalate was detrimental to As(III) removal at pH 7.0 due to its competition for photo-generated hole ( h vb + ) as well as adsorption sites. Increasing dosage from 0.0 to 0.5 g·L –1 accelerated As(III) removal at both pH 3.0 and pH 7.0. ESR, radical-scavenging, and N 2 -purging experiments showed that As(III) removal was mainly achieved by photo-oxidation at pH 3.0 and HO · appeared to be the primary oxidant for the As(III) oxidation, which was strongly dependent on HO 2 · /O 2 ·– . However, adsorption served as a major pathway and photo-oxidation played a minor role at pH 7.0. As(III) photo-oxidation was predominantly attributed to the direct reaction between As(III) and h vb + under neutral conditions. In addition, O 2 played an important role in As(III) photo-oxidation under acidic and neutral conditions. Moreover, goethite remained morphologically intact and demonstrated good reusability up to five regeneration cycles. These findings show that As(III) can be effectively removed from water containing iron oxides and carboxylic acid, which is important for the remediation of arsenic-contaminated waterbodies and wastewaters.
研究领域:
环境科学
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化学
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DOI
高影响因子
CHEMOSPHERE
·
2017
·
IF 4.208
Ivan P. Pozdnyakov,Tamara E. Romanova,Xiaojiao Cai,Victoria A. Salomatova,Victor F. Plyusnin,Ping Na,Olga V. Shuvaeva
Photooxidation of As(III) in ternary As(III) – Fe(III) – Fulvic acid system at pH 4 was investigated by optical spectroscopy, steady-state photolysis (365 nm) and atomic-emission spectrometry with inductively coupled plasma techniques. It was found that at all values of [FA]/[Fe] ratio the main photoactive species is OH radical formed by photolysis of Fe(III) hydroxocomplexes. Addition of fulvic acid leads to mainly negative effect on As(III) photooxidation due to the following reasons: (i) slow dark reduction of photoactive Fe(III) species with formation of scattering particles and photoinert Fe(II) species; (ii) formation of photoreductive Fe(III)-FA complexes incapable to oxidize As(III), (iii) competition of both FA and Fe(III)-FA complexes for UVA quanta with FeOH 2+ complex and for OH radicals with As(III). Aging of ternary system is also very important parameter leading to one order decrease of quantum yields of both Fe(II) formation and As(III) photooxidation.
研究领域:
环境科学
·
化学
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2022
·Vol. 23
·期 24
·16121
·
IF 6.208
Zhenghua Zhao,Mingjie Liu,Kai Zhou,Hantao Gong,Yajing Shen,Zongbi Bao,Qiwei Yang,Qilong Ren,Zhiguo Zhang
Heterogeneous Brønsted acidic catalysts such as phosphoric acids are the conventional activators for organic transformations. However, the photocatalytic performance of these catalysts is still rarely explored. Herein, a novel Zr-based metal−organic frameworkZr-MOF-Pwith phosphoric acids as a heterogeneous photocatalyst has been fabricated, which shows high selectivity and reactivity towards the photo-oxidation of sulfides under white light illumination. A mechanism study indicates that the selective oxygenation of sulfides occurs with triplet oxygen rather than common reactive oxygen species (ROS). WhenZr-MOF-Pis irradiated, the hydroxyl group of phosphoric acid is converted into oxygen radical, which takes an electron from the sulfides, and then the activated substrates react with the triplet oxygen to form sulfoxides, avoiding the destruction of the catalysts and endowing the reaction with high substrate compatibility and fine recyclability.Keywords:metal−organic frameworks;phosphoric acid;photo-oxidation;oxygen radical
研究领域:
化学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
·
IF 7.149
Jiyuan Jin,Shujuan Zhang,Bingdang Wu,Zhihao Chen,Guoyang Zhang,Paul G. Tratnyek
Quinones are important electron shuttles as well as micropollutants in the nature. Acetylacetone (AA) is a newly recognized electron shuttle in aqueous media exposed to UV irradiation. Herein, we studied the interactions between AA and hydroquinone (QH2) under steady-state and transient photochemical conditions to clarify the possible reactions and consequences if QH2 and AA coexist in a solution. Steady-state experimental results demonstrate that the interactions between AA and QH2 were strongly affected by dissolved oxygen. In O2-rich solutions, the phototransformation of QH2 was AA-independent. Both QH2 and AA utilize O2 as the electron acceptor, but in O2-insufficient solutions, AA became an important electron acceptor for the oxidation of QH2. In all cases, the coexistence of AA increased the phototransformation of QH2, whereas the decomposition of AA in O2-saturated and oversaturated solutions was inhibited by the presence of QH2. The underlying mechanisms were investigated by a combination of laser flash photolysis (LFP) and reduction potential analysis. The LFP results show that the excited AA serves as a better electron shuttle than QH2. As a consequence, AA might regulate the redox cycling of quinones, leading to significant effects on many processes, ranging from photosynthesis and respiration to photodegradation.
研究领域:
环境科学
·
光化学
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产品关联
DOI
PubMed
高影响因子
FOOD HYDROCOLLOIDS
·
2023
·
IF 10.7
Bo-wen Yang,Sheng-yang Ji,Tian Zhao,Zhang-tie Wang,Yan-song Zhang,Qian-nan Pan,Wei-su Huang,Bai-yi Lu
Although phytosterols (PS) showed various excellent health functions, their applications in the food industry were limited by poor water solubility and high oxidation sensitivity. This study investigated the fabrication of phytosterol-enriched emulsions stabilized by different emulsifiers and evaluated the effect of different interfacial layers on the photooxidation of phytosterols and emulsions. The emulsions were prepared with Tween 20, whey protein isolate (WPI), and soy protein isolate (SPI) to achieve interfacial membranes with different properties. The SPI-dextran mixture or dextran-glycated SPI was adopted as the additional emulsifier. Compared with Tween 20, high molecular weight emulsifiers (proteins and their mixtures) exhibited stronger photooxidation stabilities and high viscosity and density of droplet interfacial membrane. The stability of PS emulsions that undergo photooxidation was impacted by the inclusion of these emulsifiers, whereas the extent of phytosterols photooxidation was, from highest to lowest, in the following order: SPI/dextran mixture > glycated SPI mixture > WPI > SPI > Tween 20. The proper SPI concentration (1.5 wt%) showed the highest interface pressure and viscosity and the higher PS stability. Moreover, the higher rheological properties and surface pressure of droplets reveal extra oxidative stability and lower oxidation rate of PS, as well as the formation of additional 7β-OH products. This work demonstrates that emulsions may be tuned toward better photooxidation oxidative stability by modifying interface composition and interfacial properties.
研究领域:
食品科学
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生物学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 11
·5206-5217
·
IF 3.925
Yajie Wang,Xianhe Gong,Xin Dong,Xiuzhen Tao,Yingchun Luo
In this study, the kinetics of arsenite (As(III)) removal in a ferrihydrite/oxalate system under irradiation was investigated, and the effects of pH, ferrihydrite dosage, As(III) initial concentration, and oxalate concentration were evaluated. Ultraviolet A (UVA) irradiation significantly promoted As(III) removal in the presence of ferrihydrite and oxalate. The greatest removal efficiency of As(III) (92.5%) was observed under the following conditions: pH 3.0, 100.0 μg L−1 As(III), 0.0125 g L−1 ferrihydrite, 0.1 mmol L−1 oxalate, and after 90 min under UVA irradiation. The removal of As(III) in the ferrihydrite/oxalate system was strongly pH-dependent. Mechanistic investigations indicated that HO˙ was the primary oxidant for As(III) photo-oxidation in the ferrihydrite/oxalate system. Surface adsorbed hydroxyl radical (HOads˙) was the dominant oxidant over the entire pH range in the presence of oxalate, and the hydroxyl radical in aqueous solution (HOaq˙) made only a small contribution under acidic conditions. The sources of HO˙ were also strongly dependent on pH; HO2˙/O2˙− was the precursor of HO˙ under acidic conditions, while photo-generated holes gradually became the main source of HO˙ as the pH increased. The photo-oxidation of As(III) mainly occurred on the surface of ferrihydrite. Although some ferrihydrite transformed into goethite during the removal process, the iron oxides showed good reusability for up to five regeneration cycles. The findings indicate that As(III) can be efficiently removed by the ferrihydrite/oxalate system and provide guidance for developing effective treatment strategies for As(III)-contaminated waters.
研究领域:
环境科学
·
化学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Baowei Cao,Dachuan He,Fei Rao,Qadeer Ul Hassan,Xiaolong Cai,Lingna Liu,Fan Xue,Gangqiang Zhu
BiOI-loaded flower-like CeO 2 (BiOI/CeO 2 ) p-n heterojunction was synthesized via a simple two-step chemical route. The phase structure and chemical states of the heterojunction were analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The transmission electron microscopic (TEM) and the scanning electron microscope (SEM) reveal the close contact between BiOI and CeO 2 . The formation of the p-n heterojunction is verified by the Mott-Schottky curves. The p-type BiOI with a narrow band-gap when loaded on CeO 2 can not only improve the separation of photogenerated electron-hole pairs but also facilitate the absorption of visible light. The photo-oxidative removal efficiency of 9%BiOI/CeO 2 among other heterojunctions for NO reaches 45.49% and remains highly stable with an efficiency of 40.40% after the five cycles. Trapping experiments and ESR measurements were conducted to explore the contribution of charge carriers and the reactive oxygen species during the photocatalytic NO removal. This work highlights that constructing such p-n heterojunction by loading BiOI on CeO 2 microstructures can significantly enhance photocatalytic NO removal.
研究领域:
环境科学
·
材料科学
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DOI
高影响因子
Nano Research
·
2020
·Vol. 14
·期 5
·1471-1478
·
IF 8.183
Shao Weiwei,Li Xiaodong,Zu Xiaolong,Liang Liang,Pan Yang,Zhu Junfa,Wang Chengming,Sun Yongfu,Xie Yi
Photooxidation provides a promising strategy for removing the dominant indoor pollutant of HCHO, while the underlying photooxidation mechanism is still unclear, especially the exact role of H 2 O molecules. Herein, we utilize in-situ spectral techniques to unveil the H 2 O-mediated HCHO photooxidation mechanism. As an example, the synthetic defective Bi 2 WO 6 ultrathin sheets realize high-rate HCHO photooxidation with the assistance of H 2 O at room temperature. In-situ electron paramagnetic resonance spectroscopy demonstrates the existence of •OH radicals, possibly stemmed from H 2 O oxidation by the photoexcited holes. Synchrotron-radiation vacuum ultraviolet photoionization mass spectroscopy and H 2 18 O isotope-labeling experiment directly evidence the formed •OH radicals as the source of oxygen atoms, trigger HCHO photooxidation to produce CO 2 , while in-situ Fourier transform infrared spectroscopy discloses the HCOO* radical is the main photooxidation intermediate. Density-functional-theory calculations further reveal the •OH formation process is the rate-limiting step, strongly verifying the critical role of H 2 O in promoting HCHO photooxidation. This work first clearly uncovers the H 2 O-mediated HCHO photooxidation mechanism, holding promise for high-efficiency indoor HCHO removal at ambient conditions.
研究领域:
环境科学
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材料科学
·
化学
✓ 已验证
DOI
高影响因子
EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY
·
2018
·Vol. 121
·期 4
·1800078
·
IF 2.2
Xue Li,Ruinan Yang,Chunling Lv,Lin Chen,Liangxiao Zhang,Xiaoxia Ding,Wen Zhang,Qi Zhang,Chundi Hu,Peiwu Li
The residues of chlorophyll induce oxidative rancidity and deterioration through photo-oxidation. However, the effect of chlorophyll on the quality of rapeseed oil is still unknown. In this study, chlorophyll is added into rapeseed oil to reach the desired treatment levels of 2, 5, and 10 mg kg −1 , while no chlorophyll is added in the control sample. Dynamic changes of the peroxide value of rapeseed oils with different chlorophyll contents exposed to light and stored in the dark at different times (0, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 days) are investigated. The results show that the peroxide value of rapeseed oil exposed to light increased significantly, especially for the oil with a high content of chlorophyll. In contrast, the peroxide value of rapeseed oil stored in the dark is nearly unchanged no matter whether extra chlorophyll is added. This study shows that chlorophyll in rapeseed oil can trigger oil oxidation, and therefore it is necessary to take measures to reduce the chlorophyll content in rapeseed oil or store rapeseed oil in the dark as soon as possible. Practical Applications : This study shows that chlorophyll in rapeseed oil can trigger oil oxidation, and therefore it is necessary to take measures to reduce the chlorophyll content in rapeseed oil. In this study, dynamic changes of peroxide values of rapeseed oils with different chlorophyll contents exposed to light and stored in the dark at different times are investigated. The results show that the peroxide value of rapeseed oil exposed to light increases significantly, especially for the rapeseed oil with a high content of chlorophyll. In conclusion, chlorophyll in rapeseed oil can trigger oil oxidation.Therefore, it is necessary to take measures to reduce the chlorophyll content in rapeseed oil or store rapeseed oil in the dark as soon as possible.
研究领域:
食品科学
·
植物化学
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产品关联
DOI
高影响因子
CHEMOSPHERE
·
2020
·
IF 5.778
Xingyun Huang,Ying Peng,Jing Xu,Feng Wu,Gilles Mailhot
Iron species have essential influence on the environmental/geochemical behaviors of arsenic species in water and soil. Colloidal ferric hydroxide (CFH) induces photooxidation of arsenite (As(III)) to arsenate (As(V)) in water at neutral pH through surface complexation and ligand-to-metal charge transfer (LMCT). However, the effect of the co-existing natural organic matter (NOM) on the complexation-photolysis in this process has remained unclear. In the present work, the photooxidation of As(III) induced by CFH was investigated in the presence of various carboxylic acids and polyphenols as simple model compounds of NOM. Two different light sources of ultraviolet A (UVA) ( λ max = 365 nm) and ultraviolet B (UVB) ( λ max = 313 nm) were used for photooxidation treatment of the experimental ternary system and the control binary system respectively. The obtained results demonstrated that all investigated NOM inhibited the photooxidation of As(III) in the As(III)/CFH system at pH 7. Moreover, the correlation analysis between the pseudo-first order rate constant k obs and various property parameters of NOM showed that the stable constant for the complexation between Fe(III) and NOM (logK Fe-NOM ) as well as the molecular weight of NOM and the percentages of total acidity of NOM exhibited significant correlations. A simple quantitative structure-activity relationship (QSAR) model was established between k obs and these three parameters utilizing a multiple linear regression method, which can be employed to estimate the photooxidation efficiency of As(III) in the presence of ferric iron and NOM. Thus, the present work contributes to the understanding of the environmental interactions between NOM and iron.
研究领域:
环境科学
·
化学
✓ 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）