APPLIED CATALYSIS B-ENVIRONMENTAL
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2016
·
IF 8.328
Kexin Li,Zhenxing Zeng,Liushui Yan,Mingxin Huo,Yihang Guo,Shenglian Luo,Xubiao Luo
A series of nonmetallic elements co-doped titanium dioxide coated carbon nitride nanotubes (C/X-TiO 2 @C 3 N 4 NTs, X = N, F, Cl) was successfully prepared by a simple sol-gel-pyrolysis process using phenolic organic pollutants, titanium butoxide, and carbon nitride nanotubes as precursors. The morphology, porosity, phase and chemical structure, and optical and electronic property of as-prepared C/X-TiO 2 @C 3 N 4 NTs were well characterized. The as-prepared C/X-TiO 2 @C 3 N 4 NTs exhibited excellent visible-light photocatalytic activity in the conventional degradation and hydrogen evolution systems compared with traditional TiO 2 /g-C 3 N 4 heterojunction, which is attributed to their unique tubular nanostructure and nonmetallic elements co-doped TiO 2 component. Subsequently, the visible-light photocatalytic activity of C/X-TiO 2 @C 3 N 4 NTs was further studied in the simultaneous hydrogen evolution with organic pollutant degradation system on the basis of our previous work. The reaction mechanisms in different photocatalytic systems were further discussed in detail.
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高影响因子
FLUID PHASE EQUILIBRIA
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2017
·
IF 2.473
Congfei Yao,Yucui Hou,Shuhang Ren,Youan Ji,Weize Wu
Phenols are important materials for the organic chemical industry. They mainly come from coal liquefaction oil, coal tar, petroleum and biomass pyrolysis oil, making the separation of phenols from oil mixtures of great commercial value. Two zwitterionic alkaloids, betaine and L-carnitine, biodegradable and environmentally benign ionic compounds , can efficiently separate phenols from oils by forming deep eutectic solvents (DESs). In this work, the phase equilibria of two ternary systems of toluene + phenol + betaine and toluene + phenol + L-carnitine were measured at 25.0 °C, 45.0 °C and 65.0 °C under atmospheric pressure. The phase behaviors of the two ternary systems were studied, which indicated that there were three kinds of phase regions: liquid, liquid-liquid, and liquid-liquid-solid. The separation of phenol from oil mixtures occurs at the latter two phase regions. Effects of temperature, zwitterionic alkaloid type and its dosage on the phase equilibrium were investigated. With decreasing temperature, the distribution and selectivity coefficients increase. L-carnitine shows better performance in separating phenol from oils via forming DES than betaine.
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GREEN CHEMISTRY
·
2016
·Vol. 18
·期 12
·3628-3639
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IF 8.506
Xiaofeng Ning,Sugang Meng,Xianliang Fu,Xiangju Ye,Shifu Chen
In this study, a nanoparticle structure of CdS with cubic phase (CdS-G) was prepared by a facile solid-state reaction at room temperature for the first time. CdS-G can be used as a highly active photocatalyst for selective oxidation of p-methoxybenzyl alcohol (pMBA) to p-methoxybenzaldehyde (pMBAD) and reduction of nitrobenzene (NB) to aniline (AL) in a coupled reaction system under green mild reaction conditions through visible light irradiation. Compared with the counterparts prepared by the conventional precipitation method (CdS-P) and hydrothermal method (CdS-H), the photocatalytic performance of CdS-G is greatly improved owing to the unique features of the nanostructure, the high surface area, pore volume, visible light absorption and photoelectric properties. The yield of pMBAD (AL) over CdS-G is about 1.6 (5.2) and 1.9 (20.8) times higher than that over CdS-P and CdS-H, respectively. The CdS-G sample exhibits excellent selectivity and stability because its valence band (VB) and conduction band (CB) positions matched well with the redox potentials of pMBA/pMBAD and NB/AL. Furthermore, the photogenerated holes and electrons can be efficiently and directly reacted with pMBA and NB, respectively. The photocatalytic selective oxidation and reduction reaction is a synergistic reaction via producing and consuming protons. The photogenerated holes and electrons could be utilized thoroughly to produce pMBAD and AL, respectively. The molar ratio of pMBA and NB was 3 : 1, and the yield of pMBAD and AL could be successfully achieved at a theoretical ratio of 1 : 1. This work highlights the promising scope for selective organic synthesis in one reaction system under mild conditions using photogenerated electrons and holes directly and simultaneously.
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高影响因子
MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 5
·1699-1704
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IF 4.831
Chen Donghua,Peng Rulin,Zhou Hong,Liu Hui
Graphene oxide quantum dots (GOQD) are capable of enhancing the green chemiluminescence (CL) of the system composed of bis (2,4,6-trichlorophenyl) oxalate, hydrogen peroxide and fluorescein (TCPO/H 2 O 2 /fluorescein). It was found that 4-nitrophenol (4-NP) causes a further enhancement of the system, and this was exploited to develop a CL detection scheme for 4-NP. The optimum reaction concentrations were established, and under these conditions the calibration plot is linear in the 1.0 to 300 pmol L −1 concentration range, with a 0.3 pmol L −1 detection limit (at 3σ).We assume that CL enhancement is due to energy transfer from GOQD to fluorescein which is promoted by the interaction of 4-NP with the GOQD. The method was applied to the determination of 4-NP in spiked tap water and river water and gave recoveries between 93.4 and 107.9 %, with relative standard deviations of <4.0 %.
Graphene oxide quantum dots (GOQD) are good enhancer of Bis(2,4,6-trichlorophenyl) oxalate (TCPO) and hydrogen peroxide chemiluminescence (CL) system. The CL emission of fluorescein can be further enhanced by GOQD and this provides an extremely sensitive detection platform for 4-nitrophenol (4-NP).
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高影响因子
CLEAN-Soil Air Water
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2016
·Vol. 45
·期 2
·1600077
·
IF 1.716
Yong-Ming Lu,Qiao-Yue Yang,Li-Ming Wang,Ming-Zhu Zhang,Wen-Qiang Guo,Zheng-Nan Cai,Dan-Dan Wang,Wei-Wei Yang,Yan Chen
Nowadays it is still of great demand to find a feasible, inexpensive and green material for industrial enzyme immobilization for wastewater treatment. In this work, horseradish peroxidase (HRP) was successfully immobilized on glutaraldehyde activated carbon nanospheres. Compared with free HRP, the immobilized one showed better tolerance of temperature and pH. Meanwhile the storability and reusability were also greatly improved after immobilization. The immobilized HRP could be used for removal of several phenolic compounds from an aqueous solution and exhibited excellent removal efficiency, especially for chlorophenols, 4-methoxyphenol, and bisphenol A. The immobilization could also make the enzyme more tolerant of ions and preserve its bioactivity. Moreover, by the introduction of support-enzyme interaction a remarkably enhanced biodegradation was observed. The biodegradation of phenols with electron-donor groups were found to be doubled after immobilization on active carbon nanospheres. These findings might be useful for further construction of immobilized enzymes for industrial applications, which exhibit excellent stability together with high activity.
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高影响因子
FOOD CHEMISTRY
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2016
·
IF 4.052
Lei Liu,Ruifen Zhang,Yuanyuan Deng,Yan Zhang,Juan Xiao,Fei Huang,Wei Wen,Mingwei Zhang
In this study, rice bran was successively steamed with α-amylase, fermented with lactic acid bacteria, and hydrolyzed with complex enzymes. The changes in phenolic profiles and antioxidant activities of the corresponding aqueous solutions from three stages were investigated. Compared to the first stage, fermentation and complex enzyme hydrolysis significantly increased the total phenolics, total flavonoids, total FRAP and ORAC values by 59.2%, 56.6%, 73.6% and 45.4%, respectively. Twelve individual phenolics present in free or soluble conjugate forms were also analyzed during the processing. Ferulic acid was released in the highest amount among different phenolics followed by protocatechuic acid. Moreover, a major proportion of phenolics existed as soluble conjugates. The results showed that fermentation and complex enzyme hydrolysis enhanced total phenolics and antioxidant activities of aqueous solution from rice bran pretreated by steaming with α-amylase. This research could provide basis for the processing of rice bran beverage rich in phenolics.
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PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 70
·66297-66306
·
IF 3.289
Tingting Chang,Yuxin Liu,Xiangyang Yan,Shaomin Liu,Haisong Zheng
In this study, a facile method was used to synthesize core–shell magnetic surface molecularly imprinted polymer (Fe3O4@MIP) nanospheres. Initially, monodisperse carboxyl-functionalized Fe3O4 nanoparticles (Fe3O4–COOH) were obtained through a one-step hydrothermal method, the imprinted layer was then synthesized directly on the surface of the magnetic core via a one-pot sol–gel method. The morphology and structural properties of the prepared magnetic nanoparticles were characterized by XRD, TEM, SEM, FT-IR and VSM. The synthesis conditions for the formation of Fe3O4@MIPs were systematically investigated. It was found that the monodispersity and morphology of Fe3O4@MIPs were highly influenced by the concentration of ammonium hydroxide (NH3·H2O), the solvent composition (methanol–water), and the molar ratio of functional monomer and cross-linker. Interestingly, the preparation process of the Fe3O4@MIPs was direct and simple without further complex modification on the surface of Fe3O4 compared with conventional imprinting methods, which makes the saturation magnetization value for the Fe3O4@MIPs samples higher than those of common obtained materials. Meanwhile, the entire process of sol–gel polymerization was shortened to 1 h, which was much shorter than typical polymerization times. The adsorption performances of Fe3O4@MIPs and Fe3O4@NIPs with optimized morphologies were evaluated in bisphenol A (BPA) aqueous solution. The results showed that the product had the advantages of large adsorption capacity, good selectivity and favourable reusability, which are ascribed to its high uniformity and monodispersity. In addition, the molecular recognition of the obtained Fe3O4@MIPs was realized in aqueous media, which is conducive to practical applications on a larger scale and makes Fe3O4@MIPs an ideal adsorption and enrichment material.
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高影响因子
FOOD CHEMISTRY
·
2016
·
IF 4.052
Lei Liu,Wei Wen,Ruifen Zhang,Zhencheng Wei,Yuanyuan Deng,Juan Xiao,Mingwei Zhang
In this study, phenolic profiles and antioxidant activity of rice bran were analyzed following successive treatment by gelatinization, liquefaction and complex enzyme hydrolysis. Compared with gelatinization alone, liquefaction slightly increased the total amount of phenolics and antioxidant activity as measured by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Complex enzyme hydrolysis significantly increased the total phenolics, flavonoids , FRAP and ORAC by 46.24%, 79.13%, 159.14% and 41.98%, respectively, compared to gelatinization alone. Furthermore, ten individual phenolics present in free or soluble conjugate forms were also analyzed following enzymatic processing. Ferulic acid experienced the largest release, followed by protocatechuic acid and then quercetin. Interestingly, a major proportion of phenolics existed as soluble conjugates , rather than free form. Overall, complex enzyme hydrolysis releases phenolics, thus increasing the antioxidant activity of rice bran extract. This study provides useful information for processing rice bran into functional beverage rich in phenolics.
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PubMed
高影响因子
MACROMOLECULES
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2016
·
IF 5.554
Zhukang Du,Biye Ren,Xueyi Chang,Renfeng Dong,Jun Peng,Zhen Tong
Hydrophobically modified ethoxylated urethanes (HEURs) belong to an important class of telechelic associative polymers for improving solution rheological properties. We designed and prepared a novel azobenzene end-functionalized HEUR polymer (AzoHEUR), which was used to investigate the effects of hydrophobicity change of end hydrophobes induced by photoisomerization of azobenzene on the solution aggregation and rheological properties. The concentrated AzoHEUR solutions show a reversible rheological property change upon alternative exposure to UV and visible light. We have demonstrated that a reversible change in hydrophilic–lipophilic balance of polymer followed by photoisomerization of azobenzene induces a reversible rearrangement of micellar junctions through loop–bridge or bridge–loop transitions, which reversibly changes not only the network connectivity but also the solution relaxation behavior. Moreover, a structural model is proposed to describe the rearrangement of micellar junctions induced by photoisomerization of azobenzene. The work will not only provide new insights into the effect of hydrophobicity change of stimuli-responsive end groups on the aggregation and rheological behavior of HEUR aqueous solutions but also open a new perspective for development of some special applications of HEURs in fabrication and transmission of soft materials, medicines, cosmetics, inks for inkjet printers, and flow rate controlling systems.
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2017
·Vol. 93
·期 5
·1347-1358
·
IF 3.135
Yu Shen,Fumin Wang,Zongzhuang Han,Xubin Zhang
BACKGROUND ZSM-5 zeolites are of great importance in industrial catalysis. However, the diffusion limitations caused by small pore opening restrict the extent of catalytic conversions over conventional ZSM-5. Many studies have shown that mass transfer in zeolite channels can be improved by controlling the morphology or creating additional mesoporosity. Here, the catalytic performance is further improved by the creation of hollow structure and intracrystalline mesopores in ZSM-5 zeolite. RESULTS The characterization results demonstrated that hollow ZSM-5 with intracrystalline mesopores can be synthesized by using a simple one-step hydrothermal strategy with a commercial gemini-type cationic surfactant containing hydrophilic hydroxyl groups. Compared with the Fe-substituted conventional ZSM-5, the Fe-substituted hollow ZSM-5 with intracrystalline mesopores show remarkably enhanced catalytic performance in the hydroxylation of phenol. About 52.2% conversion of phenol can be obtained with almost 96.8% selectivity to dihydroxybenzenes. The catalytic activity remained almost unchanged after five cycles. CONCLUSION The newly created hollow structure and intracrystalline mesopores in ZSM-5 zeolite showed enhanced catalytic activity and reusability for the hydroxylation of phenol, which is higher than most reported systems. The prepared catalyst is a promising alternative material for the hydroxylation of phenol. © 2017 Society of Chemical Industry
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2016
·
IF 3.299
Yuwei Pan,Minghua Zhou,Xiang Li,Liting Xu,Zhuoxuan Tang,Mengmeng Liu
A new modified Fenton-like process (pre-magnetization Fe 0 /H 2 O 2 ) was employed to enhance the degradation of organic pollutants and reduce reagents dosage, using azo dye of tartrazine as the model. Compared with Fe 0 /H 2 O 2 process, pre-magnetization Fe 0 /H 2 O 2 process could have 1.3–11.2 folds enhancement in the degradation rate of tartrazine at different Fe 0 dosages (0.5–4 mmol), initial pH levels (2–6.5) and H 2 O 2 dosages (0.25–2 mmol) owing to the change of Fe 0 characteristics after pre-magnetization. The contact angle of pre-magnetization Fe 0 decreased from 58.4° to 19.8° enhancing the hydrophilicity and BET increased from 0.15 m 2 /g to 1.94 m 2 /g, which improved the corrosion of Fe 0 and accelerated the generation of Fe 2+ . Similar to the case of tartrazine, pre-magnetization Fe 0 /H 2 O 2 process had remarkable improvement on many refractory contaminants. The degradation rate constant of methyl orange, orange, methylene blue, 2,4-dichlorophenol (2,4-DCP), acetylsalicylic acid, phenol and tetracycline by pre-magnetization Fe 0 /H 2 O 2 process was 5.2, 21.3, 9.2, 5.6, 12.3, 9.5 and 3 folds of that by Fe 0 /H 2 O 2 process, respectively. The “magnetic memory” of pre-magnetization Fe 0 could last 24 h which was suitable for off-site application, and the lost some or all “magnetic memory” could be recovered after second pre-magnetization. Pre-magnetization Fe 0 /H 2 O 2 is a more promising and highly efficient Fenton process since it does not require any change of the present water and wastewater treatment process , and does not need an extra energy source and complex equipment but can widen pH range and save more than 75% Fe 0 and H 2 O 2 dosages.
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 65
·60200-60205
·
IF 3.289
Honglong Li,Lin Jin,Jinglong Dong,Liu Liu,Ming Li,Yu Liu,Linghan Xiao,Yuhui Ao
Poly(phenol-formaldehyde resin)/carbon fiber composites with different ratios of graphene–Fe3O4 were manufactured through a molding press process. Fe3O4 was introduced into the graphene to avoid recombination of the layers. The effects of the amount of added graphene–Fe3O4 on the morphology, thermal conductivity, friction performance and thermal properties of the composites were investigated via scanning electron microscopy, thermal constants analysis, tribology and thermogravimetric tests. Scanning electron microscopy confirmed the enhanced friction surface of the composites and the combination of the resin with the fibers. The thermal conductivity measurements showed that the best results were achieved with 2.0 wt% graphene–Fe3O4. The friction coefficient and wear rate also decreased with the addition of graphene–Fe3O4 based on the tribological results.
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危险品化学品经营许可证（带存储）