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1.
A novel terminal‐vinyl liquid crystal crown ether (2‐[4‐(3‐undeceny‐1‐yloxy)‐phenyl]‐2‐[4′‐(4′‐carboxybenzo‐15‐crown‐5)‐phenyl] propane) (LCCE) was synthesized and used to modify hybrid silica‐based monolithic column possessing vinyl ligands for CEC. The monolithic silica matrix containing vinyl functionalities was prepared by in situ co‐condensation of tetramethoxysilane and vinyl‐trimethoxysilane via sol–gel process and chemically modified with LCCE by free radical polymerization procedure using α,α'‐azobisisobutyronitrile as an initiator. Morphology of the monolithic column was examined by SEM and mercury porosimetry and the successful incorporation of terminal‐vinyl LCCE to the vinyl‐hybrid monolith was characterized by infrared spectra. Polycyclic aromatic hydrocarbons, benzenediols, carbamate pesticides and steroids, were successfully separated on the column. The separations were dominated hydrogen bonding supplied by crown ether and hydrophobic interaction offered by the liquid crystal. The effect of ACN concentration on separation performance was studied and the result indicated that RP retention mechanism played an important role. Reproducibilities of migration times for the six selected polycyclic aromatic hydrocarbons were reasonable, with relative standard deviation less than 3.50% for five consecutive within‐column runs and were 8.38–9.11% for column‐to‐column measurements of three columns.  相似文献   

2.
Novel and innovative hierarchical analcime zeolites were prepared by adding a gemini surfactant which acted as a dual‐functional template. Through a one‐step hydrothermal process, a hierarchical analcime zeolite with abundant intracrystalline mesopores was synthesized. Powder X‐ray diffraction and N2 adsorption–desorption data show that the mesoporous composites possess both a quite a number of mesopores and analcime structure. The results suggest that the dual‐functional template can be effective in the synthesis of hierarchical analcime zeolites.  相似文献   

3.
In this work, mesoporous hollow silicon spheres modified with 3‐aminopropyl‐ triethoxysilane (APTES) of loaded hydrogen manganese oxide lithium ion sieve (APTES/HMO‐ HS) was prepared. The structure and morphology of as‐prepared APTES/HMO‐HS were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, transmission electron microscopy and nitrogen adsorption‐desorption measurements. The Brunner‐Emmet‐Teller (BET) surface areas, pore diameters and pore volumes of APTES/HMO‐HS decreased gradually, while the Li:Mn:Si molar ratios range from 1:1:50 to 1:1:10. The obtained hierarchical porous APTES/50HMO‐HS has a high specific surface area (557.1694 m2 g‐1). The lithium and rubidium ions solutions were used to measure the adsorption performance of the APTES/HMO‐HS adsorbent. The pseudo‐first‐order and pseudo‐second‐order kinetics, Langmuir and Freundlich isotherms of APTES/HMO‐HS were investigated; suggesting that the adsorption kinetics can be described by the pseudo‐second‐order kinetic model and the adsorption isotherms well fits the Langmuir isotherm equation. The obtained results show that the prepared APTES/HMO‐HS exhibits excellent abilities to simultaneously and selectively recover Li+ and Rb+ (11.22 mg·g‐1 and 8.31 mg·g‐1) and have a promising application in the simultaneous adsorption of lithium and rubidium ions.  相似文献   

4.
Several hollow porous organic polymers were conveniently fabricated by poly‐condensation of tetraphenyl porphyrin (TPP), tetrabiphenyl porphyrin (TBPP), or triphenylbenzene (TPB), with nano‐sized ZnO particles as template and AlCl3 as catalyst. The hollow polymers exhibit much enhanced adsorption capacity for organic dyes in aqueous solution relative to the pristine polymers. Particularly, the hollow polymer based on TBPP (h‐COP‐P) displays high adsorption capacity (460 mg/g within 500 min) as well as good recycling performance toward Rhodamine B. This capacity is about three times larger than that of corresponding pristine POPs (COP‐P) and is even comparable with the best performed organic polymers reports to date, which is ascribed to its unique hydrophobic hollow structure. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1329–1337  相似文献   

5.
In this work, a quantum mechanical research of five lariat crown ethers(LCEs), 2‐methoxy‐15‐crown‐5( A ), N‐methoxy‐4‐aza‐15‐crown‐5( B ), N‐methoxy‐4‐aza‐18‐crown‐6( C ), N‐methoxyethyl‐4‐aza‐18‐crown‐6( D ), N,N′‐bis(2‐metho xyethyl)‐4,13‐diaza‐18‐crown‐6( E ), which are based on either 15‐crown‐5 or 18‐crown‐6 frameworks and contain various pendant arms extending from either carbon or nitrogen atoms on the crown frameworks, had been done using density functional theory with B3LYP/6‐31G* method to obtain the electronic and geometrical structures of the LCEs and their complexes with alkali metal ions: Na+ and K+. The nucleophilicity of LCEs had been investigated by the Fukui functions. For complexes, the match between the cation and cavity size, the status of interaction between alkali metal ions and donor atoms in the LCEs, and the sidearm effect of the LCEs had been analyzed through the other calculated parameters, such as, highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, and energy gaps. In addition, the enthalpies of complexation reaction had been studied by the calculated thermodynamic data (298 K). The calculated results are all in a good agreement with the experimental data for the complexes. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009  相似文献   

6.
A simple one‐pot approach based on molecularly imprinted polymer shells dispersed on the surface of silica for simultaneous determination of rhodamine B and dibenzyl phthalate (DBzP) has been developed. Highly dense molecularly imprinted polymer shells were formed in the mixture of acetonitrile and toluene by the copolymerization of methacrylic acid and ethylene glycol dimethacrylate, as well as two templates, rhodamine B and dibenzyl phthalate, directed by the vinyl end groups functional monolayer at surface silica microspheres after 3‐methacryloxypropyl trimethoxysilane modification. The obtained imprinted polymer shells showed large average pore diameter (102.5 nm) and about 100 nm shell thickness. The imprinted particles also showed high imprinting factor (αRhB = 3.52 and αDBzP = 3.94), rapid binding kinetics, and excellent selective affinity capacity for rhodamine B and dibenzyl phthalate containing another three competitors in mixed solution. Moreover, the imprinted particles coupled with ultra high performance liquid chromatography was successfully applied to simultaneous analysis of rhodamine B and dibenzyl phthalate in two spiked beverage samples with average recoveries in the range of 88.0−93.0% for rhodamine B and 84.0–92.0% for dibenzyl phthalate with the relative standard deviation lower than 5.1%.  相似文献   

7.
In this work, a novel dual‐template magnetic molecularly imprinted polymer particle for dicofol and chlorpyrifos‐methyl was prepared through oil‐in‐water emulsifier‐free emulsion technology. The resulting magnetic particles were characterized with electron microscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction. It was found that as‐prepared particles were well‐shaped spheres with multi‐hollow structures and of a size around 125 μm. Meanwhile it showed a good magnetic sensitivity. The results testified that multi‐hollow magnetic molecularly imprinted polymers possessed excellent recognition capacity and fast kinetic binding behavior to the objective molecules. The maximum binding amounts toward dicofol and chlorpyrifos‐methyl were 31.46 and 25.23 mg/g, respectively. The feasibility of the use of the particles as a solid‐phase extraction sorbent was evaluated. Satisfactory recoveries ranging from 90.62 to 111.47 and 91.07 to 94.03% were obtained for dicofol and chlorpyrifos‐methyl, respectively, spiked at three concentration levels from real samples. The Langmuir isotherm equation provided an excellent fit to the equilibrium sorption data of either dicofol or chlorpyrifos‐methyl. It provided a novel way to advise dual‐template magnetic molecularly imprinted polymer particles to adsorb pesticides with high selectivity.  相似文献   

8.
Various cross‐linked amino starches were used for chromium (VI) adsorption in the environmental protection area. In order to improve chromium (VI) adsorption, the new cross‐linked amino starch with porous structure (CPS) was synthesized by reverse emulsion polymerization, using waxy corn starch after enzyme hydrolysis (ES) as raw material, N,N′‐methylene‐bis‐acrylamide (MBAA) as cross‐linking agent, and ceric ammonium nitrate as initiator. The effects of the volume ratio of oil phase/aqueous phase, the content of emulsifiers, ES, and MBAA on the swelling, solubility property, chromium (VI) adsorption capacity, grafting ratio, and conversion ratio of CPS were investigated. The properties and morphology of CPS have been characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The maximum adsorption capacity for chromium (VI) ions of CPS reached 28.83 mg/g when the synthesis condition of CPS was controlled as Voil: VH2O 8:1, emulsifier 9%, starch 2%, and MBAA 10%. The new adsorption peaks of CPS at 1641 cm?1 and 1541 cm?1 proved the cross‐linking reaction between ES and MBAA. The thermal decomposition temperature of CPS was improved to 250°C, and the gelatinization temperature and enthalpy value of CPS were decreased compared with ES because of the occurrence of the cross‐linking reaction. The CPS was like a sponge with a large amount of pores, and the size of these pores was 5 µm. CPS also exhibited superior adsorption property to other heavy metal ions such as cadmium (II) and lead (II) (17.37 and 35.56 mg/g). Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

9.
Ni‐based layer‐structured cathode materials are more vulnerable to moisture than conventional LiCoO2 cathodes, adsorbing more water and easily forming LiOH on the surface. This study investigated the moisture adsorption mechanism on the surface of layer‐structured cathodes. The behavior of water molecules on LiCoO2 and LiNiO2 surfaces were simulated and the structural and chemical changes during the adsorption process were analyzed by first‐principles methods. It was found that the adsorption occurs via two types of mechanism: one involving ionic interactions between Li on the crystal surface and O in the adsorbate, and the other involving covalent bonding between the transition metal (TM) on the surface and O in the adsorbate, which restores the coordination of the TM by recovering its broken bonds. The difference between the water adsorption behaviors of Ni‐based and Co‐based layer‐structured cathodes was found to be mainly due to the ionic‐interaction‐driven adsorption on the (003) surface.  相似文献   

10.
Novel hierarchical Beta zeolites have been successfully synthesized via a one‐pot dual‐templates strategy utilizing gemini organic surfactant and tetraethylammonium hydroxide (TEAOH)through hydrothermal process. The influence of several parameters on the formation of hierarchical Beta zeolite, the change in acidity and a possible growth scheme were systematically investigated. The physicochemical properties of these catalysts were characterized by PXRD, BET, SEM, HRTEM SAED, TG and NH3‐TPD techniques, and the performance as acid catalysts was verified using the transformation of EtOH as a model reaction. On one hand, WAXRD data indicated that decreasing the temperature of synthesis and increasing amounts of C12‐6‐12 in the process of synthesis resulted in lower crystallinity of Beta zeolites due to the BEA nuclei formation and crystal growth constrained by C12‐6‐12. On the other hand, SAXRD and HRTEM data evidenced that C12‐6‐12 initially generated a pseudo‐ordered mesoporous phase which was then partially occupied by the zeolite. After a period of ~96 h for crystallization, the hierarchy zeolite possessing 765.7 m2·g‐1 of Brunauer‐Emmett‐Tellerarea, and average mesopore size distribution of 3.51 nm can be synthesized, and its microporous structure has a good crystallinity and lower amounts of acid sites than that of the microporous Beta one. Furthermore, the as‐obtained hierarchical zeolite displayed lower deactivation rate mainly due to the less coke formation on the surface of catalyst. It is expected to develop more considerable potential application value for the hierarchical Beta zeolite structure in the near future.  相似文献   

11.
《中国化学会会志》2018,65(8):940-950
Magnetic carboxyl‐coated silica iron oxide nanoparticles (Fe3O4@SiO2‐COOH NPs) were successfully synthesized, characterized, and then applied as a nano‐adsorbent for removal of malachite green (MG) from aqueous solutions. According to the experimental results, about 97.5% of MG could be removed from aqueous solutions using an adsorbent amount of 0.5 g/L at pH = 9 in 120 min. The kinetics and equilibrium adsorptions is well‐described by the pseudo‐second‐order kinetics and Langmuir model with the maximum absorption capacity of 263.16 mg/g, respectively. Thermodynamic studies showed that the adsorption of the hazardous MG dye was spontaneous and endothermic with a random process.  相似文献   

12.
Owing to the remarkable physicochemical properties such as hydrophobicity, conductivity, elasticity, and light weight, graphene‐based materials have emerged as one of the most appealing carbon allotropes in materials science and chemical engineering. Unfortunately, pristine graphene materials lack functional groups for further modification, severely hindering their practical applications. To render graphene materials with special characters for different applications, graphene oxide or reduced graphene oxide has been functionalized with different organic agents and assembled together, via covalent binding and various noncovalent forces such as π–π interaction, electrostatic interaction, and hydrogen bonding. In this review, we briefly discuss the state‐of‐the‐art synthetic strategies and properties of organic‐functionalized graphene‐based materials, and then, present the prospective applications of organic‐functionalized graphene‐based materials in sample preparation.  相似文献   

13.
Submicron, non‐porous, chiral silica stationary phase has been prepared by the immobilization of functionalized β‐CD derivatives to isocyanate‐modified silica via chemical reaction and applied to the pressurized capillary electrochromatography (pCEC) enantio‐separation of various chiral compounds. The submicron, non‐porous, cyclodextrin‐based chiral stationary phases (sub_μm‐CSP2) exhibited excellent chiral recognition of a wide range of analytes including clenbuterol hydrochloride, mexiletine hydrochloride, chlorpheniramine maleate, esmolol hydrochloride, and metoprolol tartrate. The synthesized submicron particles were regularly spherical and uniformly non‐porous with an average diameter of around 800 nm and a mean pore size of less than 2 nm. The synthesized chiral stationary phase was packed into 10 cm × 100 μm id capillary columns. The sub_μm‐CSP2 column used in the pCEC system showed better separation of the racemates and at a higher rate compared to those used in the capillary liquid chromatography mode (cLC) system. The sub_μm‐CSP2 possessed high mechanical strength, high stereoselectivity, and long lifespan, demonstrating rapid enantio‐separation and good resolution of samples. The column provided an efficiency of up to 170 000 plates/m for n‐propylbenzene.  相似文献   

14.
Calixarenes have been drawing tremendous interest due to their special structure, superior properties and numerous applications. In this work, a novel adsorbent material, calix[4]arenes functionalized dual‐imprinted mesoporous film (DIMFs) for the simultaneous selective recovery of Li(I) and Rb(I), was prepared via surface ionic imprinting. Compared with ordinary adsorbent materials, the synthesis process of the films used a cheap bio‐template and did not require extra steps but significantly enhances adsorption properties. The morphology and structure of prepared DIMFs were characterized by scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT‐IR) and nitrogen adsorption–desorption measurements. Adsorption parameters (pH and temperature), adsorption kinetics and adsorption isotherms of the DIMFs were investigated by adsorption experiments. This novel adsorbent has inorganic–organic hybrid frameworks, high specific surface area and uniform pore size. The Langmuir and Freundlich isotherms, pseudo‐first‐order and pseudo‐second‐order kinetics of DIMFs were investigated; suggesting that the adsorption data well fits the Langmuir isotherm model, and the adsorption kinetics can be described by the pseudo‐second‐order kinetic model. In addition, dual‐imprinted mesoporous film exhibited superior selectivity for Li(I) and Rb(I). Cycle test demonstrated an outstanding of reusability, which appreciating their potential for industrial application.  相似文献   

15.
Monolithic porous copolymers with 3D structure were prepared via CO2‐in‐water high internal phase emulsions template by graft copolymerization of sodium methacrylate (MAANa) on to methyl cellulose (MC) backbone. The yielded copolymer monoliths are characterized by Fourier transform infrared spectra, scanning electron microscopy (SEM), and mechanical instrument, the swelling degree of MC‐g‐PMAANa monoliths with different crosslinker in diverse pH were investigated. The adsorption performance of monolith to Cu(II) were conducted to explore its adsorption capacity to heavy metal ions from the wastewater. Then, a strategy of in situ growth of metal‐organic frameworks (MOFs) on MC‐g‐PMAANa that adsorbed with metal ions was proposed first. The X‐ray powder diffraction, SEM, and Brunauer‐Emmett‐Teller (BET) surface area result of MC‐g‐PMAANa/MOFs composites indicated that the MOFs nanoparticles were grown uniformly on the monolith wall without destroying its original 3D porous structure. Compared with MOFs nanoparticle, MC‐g‐PMAANa/MOFs composites have advantages of easy operation and handle, which more conform to practical application. Furthermore, the antibacterial activity of MC‐g‐PMAANa/MOFs was evaluated by disk agar diffusion and optical density methods. In addition, MC‐g‐PMAANa/Cu‐BTC composite was applied to dye adsorption, which has proved the underlying application of such composites in dye removal.  相似文献   

16.
Porous silica coated by a highly hydrophilic and nonionic tentacle‐type polymeric layer was synthesized by free radical “grafting from” polymerization of N‐[2‐hydroxy‐1,1‐bis(hydroxymethyl)ethyl]‐2‐propenamide (TRIS‐acrylamide) in partly aqueous solutions. The radical initiator sites were incorporated on the silica surfaces via a two‐step reaction comprising thionyl chloride activation and subsequent reaction with tert‐butyl hydroperoxide. The surface‐bound tert‐butylperoxy groups were then used as thermally triggered initiators for graft polymerization of TRIS‐acrylamide. The synthesized materials were characterized by diffusive reflectance Fourier transform infrared specotroscopy, X‐ray photoelectron spectroscopy, and CHN elemental analysis. Photon correlation spectroscopy was used to determine changes in ζ‐potentials resulting from grafting, 29Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS‐NMR) spectroscopy was used to assess the ratio of silanol to siloxane groups in the substrate and the grafted material, and the changes in surface area and mesopore distribution were determined by nitrogen cryosorption. Chromatographic evaluation in hydrophilic interaction chromatography (HILIC) mode showed that the materials were suitable for use as stationary phases, featuring good separation efficiency, a comparatively high retention, and a selectivity that differed from most commercially available HILIC phases. A comparison of this neutral phase with a previously reported N‐(2‐hydroxypropyl)‐linked TRIS‐type hydrophilic tentacle phase with weak anion exchange functionality revealed substantial differences in retention patterns.  相似文献   

17.
Ni@diaza crown ether complex supported on magnetic nanoparticle was provided by grafting technique. The catalytic activity of Fe3O4@diaza crown ether@Ni was explored through one‐pot synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones and it was used as an efficient and recoverably constant nanocatalyst. FT‐IR, SEM, TEM, XRD, BET, ICP, EDS, and TGA techniques were employed to specify the nanocatalyst. This heterogeneous catalyst demonstrated acceptable recyclability and could be used again several times with no considerable loss of its catalytic activity.  相似文献   

18.
Peptide enrichment before mass spectrometry analysis is essential for large‐scale peptidomic studies, but challenges still remain. Herein, magnetic mesoporous silica microspheres with phenyl group modified interior pore walls were prepared by a facile sol–gel coating strategy, and were successfully applied for selective enrichment of phenyl‐containing peptides in complex biological samples. The newly prepared nanomaterials possessed abundant silanol groups in the exterior surface and numerous phenyl groups in the interior pore walls, as well as a large surface area (592.6 m2/g), large pore volume (0.33 cm3/g), uniform mesopores (3.8 nm), strong magnetic response (29.3 emu/g), and good dispersibility in aqueous solution. As a result of the unique structural properties and size‐exclusion effect, the core–shell phenyl‐functionalized magnetic mesoporous silica microspheres exhibited excellent performance in fast separation and selective enrichment of phenyl‐containing peptides, and the adsorption capacity for bradykinin reached 22.55 mg/g. In addition, selective enrichment of phenyl‐containing peptides from complex samples that are consist of peptides, large proteins, and human serum were achieved by using the as‐prepared microspheres, followed by high‐performance liquid chromatography with ultraviolet detection and electrospray ionization quadrupole time‐of‐flight mass spectrometry analysis. These results demonstrated the as‐prepared microspheres would be a potential candidate for endogenous phenyl‐containing peptides enrichment and biomarkers discovery in peptidome analysis.  相似文献   

19.
Novel type hydrogel‐clay nanocomposites based on the acrylamide (AAm)‐ 2‐acrylamido‐ 2‐methylpropane sulfonic acid (AMPS) sodium salt and clay were synthesized via in situ copolymerization in aqueous solution. Samples were characterized by determining total basic group (TGB) content and swelling degree, XRD analysis, and FTIR spectroscopy. Effects of monomer ratio and clay amount on the swelling properties of the samples were investigated. It was found that the hydrogel/clay nanocomposites exhibited improved swelling capacity compared with the hydrogels. Samples were used to remove heavy metal ions (Cu (II), Cd (II), and Pb (II)) from aqueous solution in competitive and non‐competitive conditions for the first time. The effects of time and pH of the initial metal ion solution on the adsorption capacity were investigated and selectivity properties of the samples were evaluated. It was found that incorporation of a low amount of clay (10% (wt)) into the polymer structure increased the heavy metal ion adsorption capacity of the sample. It was concluded that the AAm‐AMPS/clay nanocomposites could be used as novel type, fast‐responsive, and high capacity sorbent materials in heavy metal removing processes. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

20.
In this research study, an efficient solid‐phase extraction procedure based on a new organometallic, effective, eco‐friendly and bio‐degradable nanoadsorbent was firstly introduced for influential pre‐concentration of Cu(II), Zn(II), Pb(II), Cd(II) and Mn(II) ions from food and water samples followed by flame atomic absorption spectrophotometric determination. This safe adsorbent consisted of silica nanoparticles chemically functionalized with di‐ethylen tri‐amine (SiO2@NH2NPs); easily prepared via an effective and simple approach. Characterization of SiO2@NH2NPs was subsequently implemented via SEM, FT‐IR and XRD; certifying high quality of the modified nanoadsorbent in terms of size, shape and surface functional groups. The effects of the main factors on the extraction efficiency were then optimized. Efficient extraction of the analytes of interest at neutral media accompanied with the aid of a bio‐compatible organometallic nanoadsorbent can be considered as valuable advantages of the proposed approach. In the optimum conditions, calibration graphs were linear in the range of 4–700 μg l?1, with higher correlation coefficients than 0.997 and limits of detection of 1.45–4.10 ng ml?1. The enrichment factor values were found to be in the span of 120–400. The resultant extraction recovery values were satisfactory; possessing the proper relative standard deviation (%, n  =  5) values of 2.05–4.28%.  相似文献   

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