POLYMER DEGRADATION AND STABILITY
·
2011
·
IF 2.594
Shumin Li,Youwei Yao
Zinc barbiturate [Zn(H 2 L) 2 ·2H 2 O, abbreviated as ZnL 2 ] was synthesized by a precipitation method in aqueous solution, and investigated as a co-stabilizer with calcium stearate (CaSt 2 ) for rigid poly(vinyl chloride) (PVC) by the discoloration test and the dehydrochlorination test at 180 °C. ZnL 2 exhibits high stabilizing effect with excellent initial colour of PVC films. In comparison with the synergistic effect of CaSt 2 /ZnSt 2 stabilizers, the CaSt 2 /ZnL 2 stabilizers in mass ratios ranging from 0.3/1.2 to 0.6/0.9 exhibit better synergistic effect. Moreover, PVC films stabilized by CaSt 2 /ZnL 2 show better initial colour with the addition of dibenzoyl methane as an auxiliary stabilizer . The mechanism of stabilizing action of ZnL 2 is also proposed. ZnL 2 may replace the labile chlorine atoms to interrupt the formation of conjugated double bonds in PVC chains, and act as the absorber of hydrogen chloride to restrain the self-catalytic dehydrochlorination.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
ENERGY & FUELS
·
2018
·
IF 3.024
Yang Chen,Shuhua Zhang,Xiuxiu Han,Xu Zhang,Mengting Yi,Siyuan Yang,Dayang Yu,Weijun Liu
The catalytic effects of CuAl layered double hydroxide (CuAl-LDH) on dechlorination and carbonization of polyvinyl chloride (PVC) during pyrolysis were investigated. The thermal degradation and combustion behaviors were researched via thermogravimetric analysis (TGA) and cone calorimetry (CONE). The released gases were evaluated in detail by thermogravimetric analysis coupled with Fourier transform infrared spectrometry (TGA-FTIR). Subsequently, elemental analysis and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) were employed to fully characterize the solid residues. The results of TGA and CONE showed that the addition of CuAl-LDH brought about the PVC degradation earlier and the char residues increase significantly. Moreover, the results of TGA-FTIR, elemental analysis, SEM-EDS, and Raman analysis revealed that the existence of CuAl-LDH accelerated the dehydrochlorination and promoted the char formation of PVC. CuAl-LDH maybe a potential catalyst applied to treat PVC waste into carbon materials to realize material and chemical recycling, which possess tremendous environmental and economic benefits.
研究领域:
材料科学
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环境科学
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化学工程
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产品关联
DOI
高影响因子
Catalysts
·
2018
·Vol. 8
·期 3
·116
·
IF 3.465
Meng Ye,Li Chen,Xiaolong Liu,Wenqing Xu,Tingyu Zhu,Guanyi Chen
A series of Ru-based mono and bimetallic materials were prepared and evaluated in the catalytic oxidation of chlorobenzene. Among the different Ru-based catalysts, 1Ru/TiO2(P25) was the most active catalyst and contributed the lowest complete oxidation temperature, suggesting that commercial P25 TiO2was the best support for Ru catalysts. After ceria oxides were introduced into the Ru catalytic system, the catalytic activity of 1Ru-5Ce/TiO2(Rutile) dramatically improved and that of P25 supported catalysts was decreased. Comparing the chlorobenzene consumption rates for 1Ru/TiO2and 1Ru-5Ce/TiO2at 280 °C, it could be concluded that monometallic Ru catalytic system was appropriate for P25 support, and the Ru-Ce bimetallic catalytic system was suitable for the rutile TiO2support. At 280 °C, for 1Ru-5Ce/TiO2(Rutile) and 1Ru-5Ce/TiO2(P25), the chlorobenzene conversion was stabilized at approximately 91% and 86%, respectively. According to the physicochemical properties of the catalysts as characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and Hydrogen temperature programmed reduction (H2-TPR), it can be concluded that (a) electrophilic Oadsspecies play an important role in VOCs oxidation; (b) abundant RuO2nanoparticles on the surface of 1Ru-5Ce/TiO2(Rutile) result in higher catalytic activity and stability; and (c) dispersion is not the major factor for the catalytic activity, rather the unique structure greatly facilitated the catalytic activity and stability.Keywords:chlorinated volatile organic compounds;chlorobenzene;catalytic oxidation;ruthenium;bimetallic catalysts
研究领域:
环境科学
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催化化学
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DOI
高影响因子
RSC Advances
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2019
·Vol. 9
·期 25
·14400-14406
·
IF 3.049
Rong-xiang Zhao,Xiu-ping Li,Chun-feng Mao,Liangpei Hou,Xiaohan Gao
N,N-Dimethylformamide hydrochloric acid/XMCln ([HDMF]Cl/XMCln, M = Zn or Fe, n = 2 or 3) was synthesized by stirring the mixture of [HDMF]Cl and metal chloride. [HDMF]Cl-based DES was characterized by FT-IR spectroscopy, ESI-MS and 1H-NMR spectroscopy. The oxidative desulfurization activity was investigated using [HDMF]Cl/0.2FeCl3 and [HDMF]Cl/ZnCl2 as the extractant and catalyst, and hydrogen peroxide (H2O2) as the oxidant. The desulfurization rate can reach up to 98.08% and 99.2% for DBT using [HDMF]Cl/0.2FeCl3 and [HDMF]Cl/ZnCl2, respectively. After recycling for 7 times, the removal rate of DBT still can reach more than 97%.
研究领域:
化学工程
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环境科学
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产品关联
DOI
PubMed
高影响因子
Food Analytical Methods
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2019
·Vol. 12
·期 8
·1871-1885
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IF 2.413
Xu Lijun,Miao Xiaohuan,Yang Zhaoguang,Li Haipu,Qiu Bo
Solid-phase extraction (SPE) was combined with dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) as a pretreatment technique for the simultaneous analysis of 11 organochlorine pesticides (OCPs) and 5 polychlorinated biphenyls (PCBs) in fish tissue. Gas chromatography with electron capture detector was used for the identification and quantification of these compounds. In the newly developed method, the acetonitrile extractant of the fish sample was cleaned up by commercialized SPE cartridges packed with acid alumina, and then mixed with water, sodium-chloride, and n-pentadecane for the purpose of target analyte enrichment via DLLME-SFO process. Effect of the parameters including SPE packing material, amount and chemical nature of extraction solvent, water volume, and salt concentration on the signal responses were investigated, and the recoveries of this method ranged between 70.1% and 112.3% at three spiked levels under the optimized conditions. The calibration curves were found to be linear in the range of 1.56–312.5 μg L −1 , and the limits of detection ranged from 0.372 to 1.12 μg kg −1 . Comparing the other reported pretreatment method, the presented one was sensitive, time-saving, and environmentally friendly.
研究领域:
分析化学
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环境科学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
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2019
·Vol. 9
·期 18
·5130-5141
·
IF 5.726
Shuang Song,Qiuxiang Liu,Jinhui Fang,Weiting Yu
The reductive dechlorination of chlorinated organic compounds (COCs) is very important to reduce the toxicity of waste effluents produced from pharmaceutical, electronics, dyestuff, pesticide, paper, and plastics industries. Electrochemical dechlorination as a green technology under mild reaction conditions is widely used in the reductive dechlorination of COCs using Pd as the electrode. Currently, the challenges of this method are the need to use large Pd loadings and the low dechlorination efficiency. Efforts were made in this work to reduce the loading of Pd and improve the efficiency using 2,4-dichlorophenoxyacetic acid (2,4-D) as a probe molecule for COCs in dechlorination. In this study, Pd-anchored Ni(OH)2/Ni-foam bifunctional electrodes were prepared in situ and for the first time applied in the reductive dechlorination of COCs. The results indicate that the dechlorination efficiency of 2,4-D can be enhanced on Pd-anchored Ni(OH)2/Ni-foam bifunctional electrodes even at a low Pd loading (<2 mg cm−2). A synergistic effect is found for 2,4-D dechlorination: H* formation on Ni(OH)2 and dechlorination steps on Pd. The enhanced dechlorination efficiency might be related to the shortened transport route between Ni(OH)2 and Pd active centers for H*.
研究领域:
环境科学
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电化学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2017
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IF 3.359
Chuanlin Fan,Haitao Yang,Qingshan Zhu
Given the strong demands for high purity vanadium products dedicated for all-vanadium redox flow battery (VRFB), numerous preparation technologies have been developed. One of them, the chloride process that using vanadium oxytrichloride (VOCl 3 ) as purification intermediate presents distinct technical advantages. The intermediate is readily purified via distillation process to remove most of the impurities. However, the trace titanium tetrachloride (TiCl 4 ) is difficult to be removed, due to close saturated vapor pressures. In present work, based on thermodynamic calculation and analyses, we found that TiCl 4 reacts with water significant preferentially to form the corresponding oxide, compared with VOCl 3 . Then we proposed a novel method to remove trace TiCl 4 from VOCl 3 by selective hydrolysis – distillation. The related experiments were conducted and validated the feasibility of the innovative process. Vanadium pentoxide (V 2 O 5 ) with purity higher than 99.99 wt% (4N) was further prepared from the purified VOCl 3 by precipitation – calcination .
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2014
·Vol. 132
·期 10
·
IF 1.64
Hao Li,Ping Yu,Haigang Li,Yunbai Luo
Membrane-based separation technology is one of the most active separation technologies being employed in water treatment. Polyamides (PA) are widely used membrane materials because they exhibit excellent performance, such as high flux with high salt rejection, and enhanced stability against wide range of pH and temperature. Unfortunately, PA membranes exhibit extremely poor resistance to chlorine leading to increased operation costs and decreased membrane lifetime. In this study, we find new ways for prolonging membrane lifetime and reducing the operating costs by investigating the chlorination and modification of PA membranes. Varying concentrations of hypochlorite were used to chlorinate a commercial reverse osmosis membrane (BW-30, DOW). The results showed that short-time exposure to high concentrations of hypochlorite could cause more serious problems to membranes than long-time exposure to low concentrations under the similar total exposure. The performance of the chlorinated membranes was recovered to some extent after treatment with NaOH solution (pH 10), indicating that the alkali treatment could initiate the reversible regeneration of chlorinated membranes. Furthermore, an industrial grade epoxy resin was used to modify the membranes to enhance the chlorine resistance via the reaction between the amide nitrogen and epoxy bond. The successful modifications were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. Moreover, the chlorination tests showed that the modifications performed in these experiments enhanced the chlorine resistance of the membranes, especially for the membranes exposed to low concentration of chlorine. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41584.
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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DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
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2018
·
IF 2.441
Xuran Wang,Ming Gao,Jiajia Gao,Xuedong Wang,Meiping Ma,Huili Wang
Herein, we established an ionic liquid (IL)-based liquid-solid transformation microextraction (IL-LTME) combined with HPLC-UV detection for the simultaneous determination of triclosan (TCS) and its methylated product, methyltriclosan (MTCS), in human fluids. The IL-LTME method was based on an in situ metathesis between hydrophilic IL and ion-exchange salt to form a solid hydrophobic IL. According to the above principle, a hydrophilic IL, [C 12 MIM]Br, was selected as the extractant, and NH 4 PF 6 as ion-exchange salt. The prominent advantages of the newly developed method are: (1) the in-situ reaction between the extractant [C 12 MIM]Br and ion-exchange salt NH 4 PF 6 changed the IL from hydrophilic to hydrophobic that avoiding the stick of ionic liquid on the tube wall; (2) bubbling with NH 3 greatly increased the contact area between IL-extractant and analytes resulting in improved extraction recovery; and (3) solidification of the [C 12 MIM] PF 6 provided a good separation and avoided the use of specialized equipment. A series of main parameters were optimized by single-factor screening and central composite design as follows: 0.9 mL of NaOH, 2.0 min of second ultrasonically time, 10 min of centrifugation time, 21 mg of extractant [C 12 MIM]PF 6 , 2.4 min of ultrasonic time, 65 mg of NH 4 PF 6 and 13.8 min of cooling time. Under the optimized conditions, the limits of detection for TCS and MTCS were 0.126–0.161 μg L −1 in plasma samples, and 0.211–0.254 μg L −1 in urine samples, respectively. The extraction recoveries for TCS and MTCS were in the range of 94.1–103.8%. The intra-day and inter-day precisions were 1.00–4.74% and 1.02–5.21%, respectively. In general, the IL-LTME method is environment-friendly, time-saving, economical, high efficient and robust with low detection limits and high recoveries. Thus, the newly developed method has excellent prospects for sample pretreatment and analysis of trace TCS and MTCS in blood and urine samples.
研究领域:
分析化学
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环境科学
·
医学
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产品关联
DOI
PubMed
高影响因子
WASTE MANAGEMENT
·
2018
·
IF 4.723
Ming-Xiu Zhan,Long-Jie Ji,Yu-Feng Ma,Wang-Ruochen Chen,Sheng-Yong Lu
Catalytic oxidation is regarded an effective technique to control the emissions of chlorinated benzenes (CBzs) and polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) from waste incinerators . Among the numerous factors affecting the degradation efficiency of CBzs and PCDD/Fs, limited attention has been paid to the impact of hydrochloric acid (HCl) present in the flue gas . This study investigates how HCl affects the catalytic degradation of 1,2-dichlorbenzene (1,2-DCBz) at different reaction times and temperature regimes. The results showed that the removal efficiency of 1,2-DCBz, which was achieved by the V 2 O 5 /WO 3 -TiO 2 (VWTi) catalyst, decreased the largest by 10% in the presence of HCl. Furthermore, it was found that the increasing concentration of water vapor hindered the degradation efficiency of 1,2-DCBz. No relationship between the process temperature and the destruction efficiency of PCDD/Fs was observed in the presence of HCl. Potential increasing of the removal efficiency of 1,2-DCBz was confirmed by adding different amount of activated carbon (AC) in the presence of HCl.
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
IRANIAN POLYMER JOURNAL
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2017
·Vol. 26
·期 3
·205-211
·
IF 1.422
Zhou Min-Jie,He Fang,Wu Hu,Wang Guo-Xiang,Liu Li-Chao,Xu Wenyuan
Fe-mediated photo-induced atom transfer radical polymerization (ATRP) of methyl methacrylate was studied with chlorophyll A as photoredox catalyst in the absence of ligands. This is the first report on photo-induced and FeBr 3 -mediated ATRP. A low-cost and environmentally friendly ATRP is provided in this system. A good linear semi-logarithmic plot of polymerization kinetics is the first-order time conversion, and narrow molecular weight distributions explain the well-controlled behavior. The measured number average molecular weight, M
n,GPC (determined by gel permeation chromatography), is increased with monomer conversion, and it is in good agreement with the theoretical values ( M
n,th ). The effect of FeBr 3 is studied with respect to the polymerization. The values of the resultant PMMA increased with reduced FeBr 3 concentration. In this system, the effect of periodic light/off process has been investigated through chain growth instantly turned on and off in response to the visible light. The polymerization was controllable even though the concentration of Fe-based catalyst was dropped to 4 ppm. The chain-end group having a functionality in the synthesized poly(methyl methacrylate) was characterized by nuclear magnetic resonance spectrometry ( 1 H NMR). However, chain extension experiments show reserved chain-end functionality in the synthesized polymers and further confirm the “living” feature of the Fe-mediated photo-induced atom transfer radical polymerization.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2017
·
IF 5.401
Lisha Zhang,Pei Song,Hao Long,Meng Meng,Yongmei Yin,Rimo Xi
Amlodipine is one of the most important anti-hypertension agents and S-amlodipine is 1000 folds more efficient than R-amlodipine. However, chiral separation of amlodipine remains a challenge. Here we present an effective strategy for chiral resolution of amlodipine using anti-S-amlodipine antibody for ultra-specific capture and magnetic beads for convenient collecting. The collected enantiomers are ultra-pure based on the chiral HPLC identification. Simultaneously, the captured S-amlodipine could be quantitatively detected with a linear range from 0.1 to 1000 ng mL −1 ( R 2 = 0.9937), along with a limit of detection of 0.04 ng mL −1 . The advantages of the developed magnetic electrochemical biosensor for amlodipine include specific chiral separation, sensitive quantitation, easy-to-operate procedures and time-saving protocols. This method is demonstrated as a novel tool for highly confident separation and quantification of amlodipine enantiomers, in this study. The magnetic biosensor may open up new avenues for intensive study of amlodipine enantiomers and thus be potential in clinical pharmacy and pharmacokinetics studies.
研究领域:
药理学
·
分析化学
·
生物医学工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）