JOURNAL OF APPLIED POLYMER SCIENCE
·
2012
·Vol. 128
·期 6
·3846-3852
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IF 1.289
Hong Zhou,Yeping Xu,Hongwu Tong,Yuxin Liu,Fang Han,Xiangyang Yan,Shaomin Liu
Molecularly imprinted polymers (MIP) with high performance in selectively recognizing bisphenol A (BPA) were prepared by using a novel and facile surface molecular-imprinting technique. Vinyl-functionalized, monodispersed silica spheres were synthesized by a one-step emulsion reaction in aqueous solution. Then, BPA surface molecularly imprinted polymers (SMIP) were prepared by polymerization with 4-vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. Maximal sorption capacity ( Q max ) of the resulting SMIP was up to 600 μmol g −1 , while that of nonimprinted polymers was only 314.68 μmol g −1 . Kinetic binding study showed that sorption capacity reached 70% of Q max in 20 min and sorption equilibrium at 80 min. SMIP had excellent accessibility and affinity toward BPA, for the selectivity coefficients of SMIP for BPA in respect to phenol, p-tert -butylphenol, and o -phenylphenol were 3.39, 3.35, and 3.02, respectively. The reusage process verified the SMIP owning admirably stable adsorption capacity toward BPA for eight times. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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Journal of Materials Chemistry A
·
2014
·Vol. 3
·期 8
·4307-4313
·
IF 0
Xianchun Liu,Renxi Jin,Dashu Chen,Lin Chen,Shuangxi Xing,Hongzhu Xing,Yan Xing,Zhongmin Su
In this study, we report a simple in situ auto-reduction strategy for the fabrication of Ag@FDU-15 nanocomposites, in which the small sized Ag nanoparticles are monodispersed in the channels of FDU-15 ordered mesopolymers. The as-prepared Ag@FDU-15 nanocomposites were characterized by small and wide angle X-ray diffraction (XRD), nitrogen sorption, thermo-gravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). TEM results show that the silver nanoparticles are uniformly dispersed with a mean diameter of 5.6 ± 0.5 nm. When used as a hydrogenation catalyst, the Ag@FDU-15 nanocomposites exhibit excellent catalytic performance and reusability for the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4.
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OPTICS EXPRESS
·
2015
·Vol. 23
·期 13
·17487-17510
·
IF 3.488
Dibo Hou,Jian Zhang,Zheling Yang,Shu Liu,Pingjie Huang,Guangxin Zhang
The issue of distribution water quality security ensuring is recently attracting global attention due to the potential threat from harmful contaminants. The real-time monitoring based on ultraviolet optical sensors is a promising technique. This method is of reagent-free, low maintenance cost, rapid analysis and wide cover range. However, the ultraviolet absorption spectra are of large size and easily interfered. While within the on-site application, there is almost no prior knowledge like spectral characteristics of potential contaminants before determined. Meanwhile, the concept of normal water quality is also varying due to the operating condition. In this paper, a procedure based on multivariate statistical analysis is proposed to detect distribution water quality anomaly based on ultraviolet optical sensors. Firstly, the principal component analysis is employed to capture the main variety features from the spectral matrix and reduce the dimensionality. A new statistical variable is then constructed and used for evaluating the local outlying degree according to the chi-square distribution in the principal component subspace. The possibility of anomaly of the latest observation is calculated by the accumulation of the outlying degrees from the adjacent previous observations. To develop a more reliable anomaly detection procedure, several key parameters are discussed. By utilizing the proposed methods, the distribution water quality anomalies and the optical abnormal changes can be detected. The contaminants intrusion experiment is conducted in a pilot-scale distribution system by injecting phenol solution. The effectiveness of the proposed procedure is finally testified using the experimental spectral data.
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CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Tongtong Han,Yuanlong Xiao,Minman Tong,Hongliang Huang,Dahuan Liu,Luyan Wang,Chongli Zhong
A series of CNT@MIL-68(Al) composites with different carbon nanotubes (CNTs) loadings have been synthesized and characterized by SEM, TEM, PXRD, FT-IR, TGA, and N 2 adsorption. As evidenced from SEM and TEM images, the incorporation of CNTs can result in better dispersity of MIL-68(Al) in composites and smaller particle size than pure MIL-68(Al). Adding appropriate amounts of CNTs increases both the BET surface areas and the total volume of small micorpores (<16 Å), leading to largely improved performance of adsorptive removal of phenol from aqueous solution. In the industrial concentration range of phenol, the adsorption capacity of 0.75% CNT@MIL-68(Al) was improved up to 188.7% compared with the pristine MIL-68(Al), possibly due to the increase of small micropores introduced by the incorporation of CNTs. Regeneration experiments demonstrated that the composites are stable with good regenerability for at least five cycles. This work shows that the composites formed by the combination of CNTs and MOFs may find promising applications in liquid phase adsorption.
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RSC Advances
·
2014
·Vol. 4
·期 91
·49924-49929
·
IF 3.708
Gang Feng,Zhen Liu,Ping Chen,Hui Lou
Solvents play a pivotal role in many chemical reactions as well as in upgrading of pyrolysis bio-oil. Herein we report a systematic study of the effects of solvents such as water, methanol, ethanol, propanol, butanol, acetone, ethyl acetate, tetrahydrofuran and hexane on hydrogenation of a lignin-derived component of pyrolysis bio-oil, phenol, over activated carbon supported palladium catalysts. The solvents were classified into four groups so as to better understand the effect of them. For hydrogen bond donor–hydrogen bond acceptor (HBD–HBA) solvents and hydrogen bond acceptor (HBA) solvents, the conversion of phenol decreased with increasing polarity/polarizability π*. Phenol was converted completely in hexane or water at 250 °C. However, in methanol or ethanol, it was converted partially. Synergistic action of multiple factors had an effect on the hydrogenation of phenol. To convert phenol better, water and hexane as solvents were excellent in upgrading of pyrolysis bio-oil.
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FOOD CHEMISTRY
·
2014
·
IF 3.259
Zai-yong Li,Hong-jiang Quan,Cheng-bin Gong,Yu-zhu Yang,Qian Tang,Yu-bo Wei,Xue-bing Ma,Hon-wah Lam
A novel photoresponsive molecularly imprinted polymer (MIP) was developed for the selective extraction of guanine from complex samples. The photoresponsive MIP was fabricated using guanine as the template, water-soluble 5-[(4-(methacryloyloxy)phenyl)diazenyl]isophthalic acid as the functional monomer, and water-soluble triethanolamine trimethacrylate as the cross-linker. The MIP displayed good selectivity toward guanine with a dissociation constant of (2.70 ± 0.16) × 10 −5 mol L −1 in aqueous media. The density of the guanine-specific receptor sites in the MIP material was (4.49 ± 0.22) μmol g −1 . Quantitatively release and uptake of guanine by the MIP occured with irradiation at 365 and 440 nm, respectively. The MIP could efficiently extract guanine from beer and then release it into aqueous media under photocontrol. This method could be used for selective separation and subsequent determination of a specific analytes from complex samples.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Yuyuan Deng,Qin Zhang,Huachuan Zhang,Chengxi Zhang,Wenhu Wang,Yi Gu
To study oxazine ring formation in benzoxazine synthesis from phenol, primary amine and formaldehyde, reactions between 2-phenylaminomethylphenol (Mannich base) and formaldehyde in homogeneous dioxane/water solution are researched. Reaction orders, rate constants at different temperatures, and activation energy are calculated, the process of reaction is proposed, and the influence of acid and base is discussed. The reaction can occur at low temperature and generate the product 3,4-dihydro-2H-3-phenyl-1,3-benzoxazine. No intermediate 2-(N-hydroxymethyl-N-phenylamino)methylphenols are observed. The concentration of a Mannich base has little effect on the reaction rate, while the reaction is first-order to formaldehyde. Based on chemical properties of formaldehyde in aqueous solution, the reaction process includes the following three steps: degradation of poly(oxymethylene) glycols to methylene glycol, dehydration of methylene glycol to formaldehyde molecule, and the reaction between a Mannich base and formaldehyde molecule to benzoxazine. Dehydration of methylene glycols to formaldehyde molecules is the rate-controlling step.
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POLYMER COMPOSITES
·
2014
·Vol. 35
·期 10
·2056-2066
·
IF 1.455
Xiangming Hu,Yanyun Zhao,Weimin Cheng,Deming Wang,Wen Nie
In this study, phenol, urea, and paraformaldehyde were used as the monomers for the one-step synthesis of phenol-urea-formaldehyde (PUF) foaming resin that was used to block air leakage in mining. An orthogonal test was used to study the effects of urea amount, catalyst amount, reaction temperature, and reaction time on the foaming property of the resin. The results showed that the optimum parameters for synthesizing PUF resin are as follows: 1 mol phenol, 0.5 mol urea, 3 mol formaldehyde equivalents of paraformaldehyde, and 0.05 mol catalyst at 75°C for 3 h. The infrared and 13 C nuclear magnetic resonance spectra of the PUF resin showed that the chemical structure of the PUF resin was significantly different from that of phenol-formaldehyde resin, indicating that a copolymerization reaction has occurred among the three components, that is, phenol, urea, and paraformaldehyde. In this study, PUF foam was prepared from catalysts and PUF resin. The results showed that the foaming capacity and oxygen index of the PUF foam were significantly improved by using urea, whereas the shrinking percentage decreased with no change in compression strength. POLYM. COMPOS., 35:2056–2066, 2014. © 2014 Society of Plastics Engineers
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Yucui Hou,Yuehong Ren,Wei Peng,Shuhang Ren,Weize Wu
Phenolic compounds, which are important substances in industry, are mainly derived from coal liquefaction oil, coal tar, and petroleum, and also from biomass via pyrolysis. However, the traditional process of separation of phenols from oil using water, NaOH, and H2SO4 causes serious environmental problems. In this work, imidazolium-based ionic liquids (ILs) were used to extract phenol from a model oil of hexane and phenol in order to reduce environmental risk. It was found that these ILs could successfully separate phenols from hexane, and a small amount of [Bmim]Cl, equimolar to that of phenol in hexane, was enough to extract phenol with a high extraction efficiency of 99%. Anions of imidazolium-based ILs have a significant influence on the phenol extraction efficiency, which follows the order: Cl– > Br– > BF4– > PF6–. But the cation of these ILs shows a relatively small influence on the extraction. Particularly, [Bmim]Cl shows best performance in terms of phenol extraction efficiency. Furthermore, it is not sensitive to temperature changes and can be performed at ambient temperature. The extracted phenol in ILs could be recovered by evaporation, and the regenerated ILs could be reused for four cycles with no obvious loss in the phenol extraction efficiency. [Bmim]Cl was also used to extract phenols from real coal liquefaction oil, and the extraction efficiency of phenols could reach 90%.
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
·
2013
·
IF 2.487
Huijun Liu,Hong Wang,Caixia Li,Lichao Wang,Zaifa Pan,Lili Wang
Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography/mass spectrometry (GC/MS) method was applied for the investigation of low molecular weight volatile organic metabolites (VOMs) in pleural effusion samples. Three important HS-SPME experimental parameters that influence extraction efficiency (fiber coating, extraction time and temperature of sampling) were optimized by a univariate optimization design. The highest extraction efficiency was obtained when sampling was performed at 50 °C for 10 min under agitation using a carboxen/polydimethylsiloxane (CAR/PDMS) fiber. A total of 36 volatile metabolites belonging to nine distinct chemical classes were identified in 40 pleural effusion samples (20 malignant effusions from lung cancer patients and 20 benign effusions from inflammatory patients). Ketones, alcohols, and benzene derivatives were the main chemical classes for the metabolomic profile of malignant effusions. The average peak areas of ketones and alcohols were much higher in malignant group compared to benign group. Together with phenols, they exhibit significant differences ( P < 0.05) between the two groups. Particularly, the average peak areas of cyclohexanone and 2-ethyl-1-hexanol in malignant effusions were significantly higher than those in benign ones. Furthermore, of the 36 identified metabolites, 5 compounds including cyclohexanone and 2-ethyl-1-hexanol were found to be statistically different (Student's t -test, P < 0.05) between the two groups by statistical analysis based on the peak areas of all identified metabolites. Among them, cyclohexanone and 2-ethyl-1-hexanol might be considered as candidate biomarkers of lung cancer to differentiate malignant from benign effusions. The results show that HS-SPME-GC/MS is a simple, rapid, sensitive and solvent-free method for the determination of VOMs in pleural effusion samples. Pleural effusion is a valuable sample source for observation of changes in VOMs for differentiation between lung cancer patients and inflammatory individuals.
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ADVANCED MATERIALS
·
2014
·Vol. 26
·期 25
·4260-4267
·
IF 15.409
Shan Cong,Yuyu Tian,Qingwen Li,Zhigang Zhao,Fengxia Geng
Graphical Tungsten oxide quantum dots (QDs) with an average size down to 1.6 nm are developed, serving as a new class of promising electrode materials, which yield efficient and fast electron/ion transport in the charge/discharge process. With a visually impressive display, the QDs present coloration/bleaching times within 1 s, which is much superior to inorganic analogues and even competitive to organic-related materials.
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ANALYTICAL LETTERS
·
2014
·
IF 1.019
Zhidong Chen,Chuangui Tang,Yanbo Zeng,Haiqing Liu,Zhengzhi Yin,Lei Li
A novel electrochemical sensor for bisphenol A was developed through the combination of a molecular imprinting technique with a multiwalled carbon nanotube paste electrode. A molecularly imprinted polymer and nonimprinted polymer were synthesized in the presence and absence of bisphenol A, and then used to prepare the electrode. The bisphenol A imprinted polymer was applied as a selective recognition element in the electrochemical sensor. Differential pulse voltammetry was used to characterize the electrochemical behavior of bisphenol A at the modified electrodes. The results showed that the imprinted sensor had highest response for bisphenol A. Parameters including the carbon paste composition, pH, and adsorption time for the imprinted sensor were optimized. Under the optimized conditions, the differential pulse voltammetry peak current was linear with the concentration of bisphenol A from 0.08 to 100.0 µM, with a detection limit of 0.022 µM. The imprinted sensor for bisphenol A exhibited good selectivity, stability, and reproducibility. This sensor was successfully used for the determination of bisphenol A in real water samples.
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