CONSTRUCTION AND BUILDING MATERIALS
·
2019
·
IF 4.046
Jianfeng Ma,Yazhuo Shang,Changjun Peng,Honglai Liu,Shuzhen Zheng,Hongxia Zhao,Shuai Qi,Qianping Ran
Air content can greatly affect the properties of concrete, therefore, the development of high efficient air-entraining agents is important. In this work, novel phosphate-modified polymers with different aryl substitutions were synthesized and used as highly efficient air-entraining agents. The structure of polymers was characterized by 1 H NMR and IR spectra. The foamability and foam stability of the different polymeric surfactants were tested in solutions. Surfactants with large steric hindrance, such as APP-6, showed superior performance of foamability and foam stability. In view of the excellent foamability properties of synthesized polymers in aqueous solution, the application of these polymers used in cement mortar as air-entraining agents were also evaluated for practical application. The surface tension, theoretical calculation and dynamic light scattering test for these polymeric surfactants were also studied. The synthetic aryl-polyether-phosphate surfactants showed higher surface activity, foamability, foam stability, and air-entraining performance compared with commercial air-entraining agent.
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 11
·9140-9150
·
IF 3.201
Jiliang Ma,Xinwen Peng,Linxin Zhong,Runcang Sun
The application of biomass-based carbonaceous solid acids in catalysis is attracting increasing attention in the field of chemistry. In this study, a heterogeneous carbon-based solid acid biocatalyst (CXH-SO3H) with regular spherical structure was synthesized from xylan-type hemicellulose (XH) by a simple two-step method. The catalyst was successfully applied in the synthesis of O- and N-heterocycles with yields of 80–99% and 60–97%, respectively. In view of environment and economy, CXH-SO3H shows the merits of environmental friendliness, easy operation, simple work-up, excellent yields, and the avoidance of use of organic solvents and expensive catalysts. Moreover, the as-synthesized solid acid catalyst could be used for several cycles without significant loss in its catalytic activity. The results of FT-IR, XRD, and SEM showed that no distinct differences in physico-chemical structures of CXH-SO3H were observed. Thus, the eco-friendly CXH-SO3H catalyst is a promising candidate for green synthesis of O- and N-heterocycles from low-cost feed-stocks and has good prospect in partially substituting commercially available solid and liquid acid catalysts and precious metal catalysts.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2018
·
IF 6.434
Lingshuai Kong,Guodong Fang,Ya Kong,Meng Xie,Vinothkumar Natarajan,Dongmei Zhou,Jinhua Zhan
Wastewater systems contain a large number of compounds, such as anthropogenic aromatic pollutants and natural organic matter (NOM), and usually have pH higher than 4. Fenton-like reaction is the most widespread method for removal of organic pollutants, but their reactivity with H 2 O 2 may be inhibited by NOM due to the competition of hydroxyl radicals and chelating agents. In this work, Cu 2 O@β-cyclodextrin was developed to achieve the collaboration between molecular recognition and Fenton-like catalysis to destruct aromatic pollutants at neutral pH. In Cu 2 O@β-CD, covalent Cu O C bond was topotaxially converted from CuCl assisted by β-CD at room temperature. Covalently linked β-CD could keep humic acid from interfering catalytic performance of Cu 2 O surfaces and inhibit the leaching of copper. A higher catalytic ability was observed for Cu 2 O@β-CD with rate constant 0.0331 min −1 than Cu 2 O (0.0064 min −1 ) at neutral pH. A mechanism of synergistic catalysis was proposed on the basis of Cu + , β-CD and phenoxo-Cu 2+ complexes in the Cu 2 O@β-CD/BPA/H 2 O 2 system. The strategy of coupling molecular recognition into Fenton-like reaction provides an efficient and promising approach to the destruction of aromatic pollutants at neutral pH.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2018
·
IF 2.829
Jianfeng Ma,Yazhuo Shang,Changjun Peng,Honglai Liu,Shuzhen Zheng,Yanwei Wang,Shuai Qi,Qianping Ran
In this work, four types of comb-like dispersants and one linear dispersant were synthesized to explore the effect of dispersant structure on the bubble structure in water solution and mortar system for the first time. Dispersants were modified with different adsorption groups (i.e., carboxylic acid , phosphate ester, and sulfonic groups). Polymer structures were identified using gel permeation chromatography and infrared spectroscopy . Surface tension test indicated that the comb-like dispersants exhibited lower surface tension than that of the linear dispersants (NSF-2), thereby demonstrating that the polycarboxylate superplasticizer (PCE) solutions possessed high surface activity. The analysis of the foamability and foam stability of the comb-like and linear dispersants were comprehensively investigated at different concentrations. Comb-like dispersants possessed higher foam height and better foamability performance than those of the linear dispersants. The bubbles of the dispersant PCE-3 were smaller in terms of the mean area and possessed higher number of bubbles than those of the other dispersants, which may be essential in reducing the viscosity of the slurry. A similar result was also obtained in the mortar system tested using the AVA instrument for PCE-3 and NSF-2. Adsorption and rheological behavior test indicated that comb-like dispersant PCE-3 is the most effective in reducing the viscosity of the slurry among all the dispersants tested. This result is consistent with that of the foamability experiment.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Jianlin Peng,Meiling Qi
This work describes the investigation of utilizing a chain-typed thiophene-based π-conjugated polymer, i . e ., poly(3-hexylthiophene) (P3HT), as the stationary phase for gas chromatography (GC). The P3HT column was statically prepared and investigated for its column efficiency, polarity, separation performance, repeatability and thermal stability. As a result, it showed moderate polarity and column efficiencies of 3260, 3310 and 3790 plates/m for 1-octanol, naphthalene and n -dodecane, respectively. As evidenced, it exhibited high-resolution performance for aliphatic and aromatic isomers, including those critical pairs such as phenanthrene/anthracene and p -/ m -benzenediol isomers. Moreover, it displayed stronger retention for alkanes, alcohols and phenols in comparison to the polysiloxane stationary phase with close polarity. Also, the P3HT column had good repeatability and reproducibility with the RSD values less than 0.05% for run-to-run, 0.17–0.54% for day-to-day and 2.7–5.2% for column-to-column, and good thermal stability up to 260 °C. This work demonstrates the promising future of the thiophene-based polymer and its derivatives in separation science.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemCatChem
·
2015
·Vol. 7
·期 16
·2485-2492
·
IF 4.556
Guangyue Xu,Jianhua Guo,Ying Zhang,Yao Fu,Jinzhu Chen,Longlong Ma,Qingxiang Guo
Graphical Phosphate aids palladium: A highly reactive, selective, compatible, stable and low-cost catalytic system for selective hydrogenation of phenol to cyclohexanone is described, which consists of well-dispersed Pd nanoparticles anchored to the hydroxylapatite surface that supports the specificity through its basic sites. The production of pure cyclohexanone under mild conditions over catalysts with high reactivity, selectivity, compatibility, stability, and low cost is still a great challenge. Here we report a hydroxyapatite-bound palladium catalyst (Pd–HAP) to demonstrate its excellent performance on phenol hydrogenation to cyclohexanone. Based on catalyst characterization, the Pd nanoclusters (≈0.9 nm) are highly dispersed and bound to phosphate in HAP. Only basic active sites on HAP surface are detected. At 25 °C and ambient H 2 pressure in water, phenol can be 100 % converted into cyclohexanone with 100 % selectivity. This system shows a universal applicability to temperature, pH, solvent, low H 2 purity, and pressure. The catalyst reveals high stability to be recycled without deactivation or morphology change; and Pd nano-clusters barely aggregate even at 400 °C. During the reaction, HAP adsorbs phenol, and Pd nanoclusters activate and spillover H 2 . The mechanism is also investigated, proposed, and verified.
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2013
·Vol. 180
·期 5
·341-346
·
IF 3.434
Hou Fang,Deng Ting,Jiang Xinyu
We have developed a simple and efficient method for dispersive liquid-liquid microextraction of 4-nitrophenol, 2-naphthol and bisphenol A in real water samples. It is making use of solidified floating organic droplets of 1-dodecanol which has low density and a proper melting point. The type and volume of extraction solvent and dispersive solvent, the effect of salts, pH value and extraction time were optimized and resulted in enrichment factors of 84 for 4-nitrophenol, 123 for 2-naphthol, and 97 for bisphenol A. The limits of detection by HPLC are 1.50, 0.10 and 1.02 ng · mL −1 , respectively. Excellent linearity is observed in the concentration range from 10 to 800 ng · mL −1 , with coefficients of correlation ranging from 0.9988 to 0.9999. The relative standard deviations (for n = 5) are from 3.2 to 5.3 %, and relative recoveries for the three phenols in tap, river and spring water range from 85.0 to 105.0 %, 98.3 to 110.0 %, and 98.6 to 109.0 %, respectively.
Chromatograms of river water blank (b) and spiked river water (a, 500 ng ∙ mL −1 ) analyzed with DLLME-SFO-HPLC. Peak identification: (1) p-nitrophenol; (2) 2-naphthol; (3) bisphenol A. Liquid-liquid microextraction method based on solidification of floating organic droplet (DLLME-SFO) has a high enrichment factor (84, 123and 97), acceptable relative recovery (85.0 %–110.0 %), good repeatability (5.27 %, 3.54 % and 3.16 %) and a wide linear range (10–800 ng · mL −1 ) for the determination of p-nitrophenol, 2-naphthol and bisphenol A.
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2014
·
IF 4.086
Junhua Li,Jun Li,Haibo Feng,Yaqian Zhang,Jianbo Jiang,Yonglan Feng,Mansheng Chen,Dong Qian
A copper nanostructures-graphene oxide (Cu/GO) hybrid as a new electrocatalyst for highly sensitive detection of 2-naphthol (2-NAP) was successfully synthesized by a one-pot and in situ chemical reduction approach. The characterization results reveal that the cubic Cu nanostructures are tightly attached onto the GO sheets in the resulting hybrid. A lower oxidation potential and a larger peak current were observed for the 2-NAP oxidation at the Cu/GO modified electrode, demonstrating the synergistic electrocatalysis from Cu nanostructures and GO sheets. Consequently, the Cu/GO hybrid exhibits a low detection limit (5.0 nM) and wide linear ranges (0.1–4.0 μM and 4.0–130.0 μM) when used as a sensing material for the sensitive detection of 2-NAP. Finally, the fabricated sensor was successfully applied in the detection of 2-NAP in real samples and satisfactory recoveries in the range of 99.3%–104.0% were achieved.
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2014
·
IF 5.825
Jun-Hui Zhang,Sheng-Ming Xie,Mei Zhang,Min Zi,Pin-Gang He,Li-Ming Yuan
Chiral nematic mesoporous silica (CNMS) has attracted widespread attention due to some unique features, such as its nematic structure, chirality, large pore size, high temperature resistance, low cost, and ease of preparation. We first reported the use of CNMS as a stationary phase for capillary gas chromatography (GC). The CNMS-coated capillary column not only gives good selectivity for the separation of linear alkanes, aromatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and isomers but also offers excellent enantioselectivity for chiral compounds. Compared with enantioseparations on commercial β-DEX 120 and Chirasil-l-Val columns, a CNMS-coated capillary column offers excellent enantioselectivity, chiral recognition complementarity, and the separation of analytes within short elution times. It can also be potentially applied in high-temperature GC at more than 350 °C. This work indicates that CNMS could soon become very attractive for separations.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2015
·
IF 4.169
Chengjiang Zhang,Gongke Li,Zhuomin Zhang
Covalent organic polymers (COPs) connected by covalent bonds are a new class of porous network materials with large surface area and potential superiority in sample pretreatment. In this study, a new hydrazone linked covalent organic polymer (HL-COP) adsorbent was well-designed and synthesized based on a simple Schiff-base reaction. The condensation of 1,4-phthalaldehyde and 1,3,5-benzenetricarbohydrazide as organic building blocks led to the synthesis of HL-COP with uniform particle size and good adsorption performance. This HL-COP adsorbent with high hydrophobic property and rich stacking π electrons contained abundant phenyl rings and imine ( C N) groups throughout the entire molecular framework. The adsorption mechanism was explored and discussed based on π–π affinity, hydrophobic effect, hydrogen bonding and electron–donor–acceptor (EDA) interaction, which contributed to its strong recognition affinity to target compounds. Enrichment factors were 305–757 for six Sudan dyes by HL-COP micro-solid phase extraction (μ-SPE), indicating its remarkable preconcentration ability. Furthermore, the adsorption amounts by HL-COP μ-SPE were 1.0–11.0 folds as those by three commonly used commercial adsorbents. Then, HL-COP was applied as adsorbent of online μ-SPE coupled with high performance liquid chromatography (HPLC) for enrichment and analysis of trace Sudan dyes in food samples with detection limit of 0.03–0.15 μg/L. The method was successfully applied for online analysis of chilli powder and sausage samples. Sudan II and Sudan III in one positive chilli powder sample were actually found and determined with concentrations of 8.3 and 6.8 μg/kg, respectively. The recoveries of chilli powder and sausage samples were in range of 75.8–108.2% and 73.8–112.6% with relative standard deviations of 1.2–8.5% and 1.9–9.4% ( n = 5), respectively. The proposed method was accurate, reliable and convenient for the online simultaneous analysis of trace Sudan dyes in food samples.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Analytical Methods
·
2014
·Vol. 6
·期 11
·3751-3757
·
IF 1.938
Xiao-Yan Xu,Xing-Guo Tian,Liang-Gen Cai,Zhen-Lin Xu,Hong-Tao Lei,Hong Wang,Yuan-Ming Sun
The demanding task of monitoring illegal dyes in foodstuffs requires sensitive detection methods. Here, a surface plasmon resonance (SPR) sensor, combined with a 75 ± 5 nm thick molecularly imprinted polymer (MIP) nanofilm as a recognition element, is used for the selective detection of Sudan dyes. The MIP-SPR sensor chip was fabricated by anchoring the MIP nanofilm of Sudan I on a gold chip via surface-initiated in situ polymerization. The surface morphology and thickness of the MIP films were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The adsorption properties of the sensor chip were studied through application as an SPR sensor. The MIP-SPR sensor exhibited excellent adsorption capacity, and high sensitivity and selectivity for Sudan dyes. The SPR response was linearly proportional to the concentration of Sudan I over the range 50–400 ng mL−1. Based on a signal-to-noise ratio of three, a detection limit of 30 ng mL−1 was established with a 400 s response time. Non-imprinted SPR sensors were compared in terms of selectivity with MIP-SPR sensors and it was found that all the recognition coefficients (α) for Sudan I–IV were greater than 1. The MIP-SPR sensor also showed reproducible response over three equilibration–adsorption–regeneration cycles.
✓ 已验证
产品关联
DOI
高影响因子
ANALYST
·
2013
·Vol. 139
·期 1
·242-250
·
IF 3.969
Juan Zhang,Wenpeng Zhang,Tao Bao,Zilin Chen
A novel capillary with hydroxyapatite (HAP) as the stationary phase was prepared for open-tubular capillary electrochromatography (OT-CEC). To immobilize HAP, a mussel-inspired polydopamine method was utilized to modify the capillary firstly, generating a polydopamine layer; and then a layer of HAP would be formed on the polydopamine layer by a biomineralization process, to produce a HAP-modified capillary (HAP@capillary). Scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) provided evidence of nanostructured HAP grown on the surface of the capillary wall. The electroosmotic flow (EOF) characteristic of the HAP@capillary was investigated by varying the percentage of acetonitrile and pH value of the buffer with thiourea as a marker, and a pH-dependent EOF from anode to cathode was observed. The HAP@capillary exhibits high column efficiency for methylbenzene, up to 151 138 plates per meter. Different kinds of compounds including alkylbenzenes, phenols and amines have been successfully separated by the HAP@capillary in CEC mode. The HAP@capillary also possessed good separation ability in capillary liquid chromatography (CLC) mode because of the relatively large ratio of HAP in the capillary; however, the separation efficiency was not as good as that in CEC mode. The reproducibilities of the HAP@capillary were evaluated, and the relative standard deviations were found to be lower than 5%.
✓ 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）