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M aleic anhydride-heptene-1-styrene terpolymer has been synthesized and modified with allyl alcohol and methylmethacrylate in order to prepare a new cross-linked functional polymer sorbent. The synthesized terpolymer, mono-allyl ester of terpolymer and synthesized cross-linked sorbent were characterized by Fourier transform infrared and 1 H NMR spe...
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... synthesized TPL was characterized by FTIR ( Figure 1a) and 1 H NMR (Figure 2) spectroscopies. The IR spectrum shows two bands at 1779 cm -1 and 1844 cm -1 , which are assigned to C=O stretching vibration and the absorption band at 1224 cm -1 corresponding to the C-O-C stretching vibration in the cyclic anhydride structure. ...
Citations
The kinetics and thermodynamics of the U(VI) adsorption process on amidoximated polypropylene-acrylonitrile-acrylic acid (AOPP-AN-AAc) fiber adsorbent were investigated by static adsorption at different temperatures. The process of uranium adsorption by the adsorbent was fitted to the pseudo-second-order kinetic model and the pseudo-second-order rate constant and the pseudo activation energy at different temperatures were determined. The thermodynamic properties of the U(VI) adsorption process by the adsorbent were also evaluated. The optimum conditions of adsorption were determined by studying the effects of U(VI) concentration, solution pH, temperature and stirring conditions on the adsorption equilibrium. The desorption and regeneration properties of U(VI) adsorbed on the adsorbent were evaluated in different media.
A novel three dimensional ZnO modified biochar-based hydrogel (ZBCG) was fabricated and employed for removing U(VI) in aqueous solution. The ZBCG hydrogel, the successful loading of ZnO modified biochar (ZBC) confirmed by SEM and FTIR, has showed a well mechanical characteristics, thermal stability, anti-swelling property and adsorption performance for U(VI) than pure hydrogels (BG). At T = 40℃, pH = 5, the maximum adsorption capacity of the Langmuir model was 239.21 mg/g. According to adsorption kinetics tests, the chemical adsorption has occupied the leading status in the adsorption process of ZBCG for U(VI). More importantly, ZBCG could be quickly separated and easily regenerated. After 5 cycles of adsorption-desorption, ZBCG have kept the uranium adsorption efficiency of 78.88%. On account of spectroscopic analyses, the mechanisms between ZBCG and U(VI) were involved ion exchange with Zn²⁺ and chelation by -OH and -COOH. This study proved that ZBCG could be considered the effective and promising material for U(VI) removement from an aqueous solution.
A group of molecularly imprinted polymer (MIP) with specific molecule identification properties for norfloxacin (NFA) was prepared by precipitation polymerization using norfloxacin-Zn2+ as template molecule, ethyleneglycol dimethacrylant as the cross-linker, methacrylic acid and 4-vinyl pyridine as functional monomer respectively. The coordination proportion of the template molecule and functional monomer was studied by ultraviolet spectrum and the characterization of the molecularly imprinted polymer can be achieved by the infrared spectrum analysis. The result indicated that dominant induction imprinted complex with the ratio 1:1 was formed between norfloxacin-Zn2+ and methacrylic acid, while the dominant conjugation imprinted complex was formed by 4-vinyl pyridine as the functional monomer with the ratio of 1:2, and the ChemDraw pictures were used to display the imprinted form of the polymers. Then the scanning electron microscopy and the particle size distribution were used to characterize the physical properties of the molecularly imprinted polymer, the result showed irregular holes and porous scattered in the prepared molecularly imprinted polymer and the non-imprinted polymer surface was dense with no holes, then the particle size of the prepared polymer was less than 100 μm and the average particle size was 39 μm. The adsorption ability of the prepared polymer were researched by the isothermal combined experiment and the result revealed that the prepared molecularly imprinted polymer using 4-vinyl pyridine with the ring space structure as the functional monomer showed better selectivity recognition ability for norfloxacin than methacrylic acid with the chain structure, the specificity adsorption was 66.84 μmol/g and the imprinted index was 4.207, and it also showed better selective ability in the nofloxacin-Zn2+ and ofloxacin-Zn2+ mixture solution, the recognition factor was 3.408. Meanwhile the selective experiment displayed that the adsorption capacity of the non-imprinted polymer was small and closed to each other, therefore the recognition factor was close to 1, this indicated that the recognition ability of the non-imprinted polymer to the adsorption substrate was non selective. © 2012 Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences.
Poly(styrene-maleic anhydride) or SMA are versatile copolymers available in different grades of molecular weight (Mw = 5500–170,000 g/mol) and molar percentage of maleic anhydride (22–50 mol-%). As specific grades can be used for the synthesis of nanoscale structures in paper industry, a better understanding of the molecular structure was needed. Therefore, a broad range of SMA grades was analyzed by means of size exclusion chromatography, infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy. While the nominal composition could be determined by 1H NMR and Raman spectroscopy, the combination with 13C NMR and FTIR allowed a more detailed characterization of the molecular structure. The high-molecular weight SMA grades show a heterogeneous molecular structure with segments including high styrene and maleic anhydride moieties, respectively. The formation of film patterns was evaluated by deposition from an acetone solution, resulting in homogeneous films, fibrous structures, or spherical shapes with decreasing diameter as a function of maleic anhydride content including primary particle sizes of 100 nm. This study illustrates intrinsic molecular features of SMA grades that are capable for self-assembly, and can provide a selection tool for future nanoparticle formulation.
Dummy molecularly imprinted polymers (DMIPs) for aniline were synthesized by a thermal polymerization method using acrylamide as a functional monomer, ethylene dimethacrylate as a crosslinker, 2,2-azobisisobutyronitrile as a free radical initiator, acetonitrile as a porogenic solvent, and analogues of aniline, namely sulfadiazine, as the template. The DMIPs that were obtained showed a high affinity to aniline compared to non-imprinted polymers. It was proven that the DMIPs obtained using sulfadiazine as the template were much better than the molecularly imprinted polymers using aniline as the template. The results indicated that the Freundlich model was fit for the adsorption model of DMIP for aniline and the adsorption model of the DMIP for aniline was multilayer adsorption. Furthermore, the results showed that the DMIP synthesized by bulk polymerization could be used as a novel adsorbent for removal of aniline from contaminated water.
