Fabrication of ordered microporous styrene‐acrylonitrile copolymer blend imprinted membranes for selective adsorption of phenol from salicylic acid using breath figure method

Highly selective, ordered microporous molecularly imprinted membranes (MIMs) for phenol were synthesized by breath figure (BF) method using styrene‐acrylonitrile copolymer (SAN) as the membrane matrix and molecularly imprinted polymer nanoparticles (nano‐MIPs) as the imprinted nanoparticles. The nano‐MIPs were synthesized by oil‐in‐water emulsion polymerization using 4‐vinyl pyridine (4‐VP), methyl methacrylate (MMA) or cinnamic acid (CA) as the functional monomer, respectively. The prepared nano‐MIPs were characterized by transmission electron microscope (TEM) and Raman, whereas MIMs were characterized by SEM, membrane flux, and selective adsorption experiments. Morphological analysis exhibited that the addition of nano‐MIPs improved the formation of ordered and well‐defined porous membrane morphology. Compared with MMA‐MIM and CA‐MIM, the 4‐VP‐MIM exhibited higher membrane flux, adsorption capacity, and stronger selective binding for phenol as well as excellent permeation selectivity for phenol. Moreover, the selective effect of 4‐VP‐MIM on phenol was strongly affected by the amount of 4‐VP imprinted nanoparticles (nano‐4‐VP‐MIPs). The experimental data revealed that the 4‐VP‐MIM containing 2.0 wt % of nano‐4‐VP‐MIPs exhibited the highest separation selectivity for the template phenol, whose selectivity coefficients for phenol relative to salicylic acid (SA) and p‐hydroxybenzoic acid (p‐HB) were 5.6770 and 5.5433, respectively, which was close to the predicted selectivity coefficient value. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42350.     

氧化石墨烯杂化分子印迹复合膜制备及性能研究

采用改进的Hummers法,通过冷冻干燥制备了氧化石墨烯(GO)。以辛弗林盐酸盐为模板分子,水溶性的丙烯酰胺为功能单体,离子液体(溴代1-丁基-3-甲基咪唑)为致孔剂,把GO加入聚合液中,制备了GO杂化的分子印迹复合膜(GO-MIM)。利用透射电镜、扫描电镜、X射线衍射和红外光谱等方法对GO及GO-MIM进行了表征。通过将分子印迹膜技术与GO相结合,明显提高了分子印迹膜的力学性能。吸附及渗透实验表明,GO-MIM可在纯水溶剂体系,对辛弗林盐酸盐具有很好的选择性吸附能力和优先透过能力,体现了明显的分子印迹效果。     

异丙酚分子印迹聚合物的制备及其结合特性

采用分子印迹技术制备了异丙酚分子印迹聚合物,并考察其结合特性和选择性。以异丙酚为模板分子,甲基丙烯酸为功能单体,二甲基丙烯酸乙二醇酯为交联剂,偶氮二异丁腈为引发剂,甲苯、正己烷为溶剂合成异丙酚分子印迹聚合物。通过平衡吸附实验,研究了异丙酚分子印迹聚合物的结合特性和选择性。Scatchard模型分析表明,在该聚合物中存在对异丙酚有不同亲和力的两类作用位点。此聚合物与异丙酚的结合要优于麝香草酚。此方法可合成异丙酚分子印迹聚合物,通过结合实验和对底物选择性考察,表明该聚合物对异丙酚具有良好的选择性。     

表面光接枝共聚法制备高通量分子印迹膜

Molecular imprinted polymer membranes (MIM) combine the merits of molecular imprint and membrane technology. In this work, a very thin of imprinted polymer that can specifically and selectively absorb the basic template (adenine) was grafted on the surface of polyvinylidene fluoride membrane by photo-grafting copolymerization. Because the molecular imprinted polymer is grafted on the surface of the matrix membrane without blocking the membrane pores, the resultant MIMs have high flux as microfiltration membrane (0.26mol·m-2·h-1 of template and flux for distilled water was 3.6ml·mim-1·cm-2 at 0.8 MPa). Moreover, the MIMs can absorb/desorb template molecules rapidly. Usually, it only takes several minutes for MIMs to absorb more than 75% of the template (adenine) in aqueous solution. And the influences of the type and amount of the functional monomers, the amount of the cross-linker on the absorption capability are discussed to determine the optimal preparation conditions.     

Preparation of molecularly imprinted CS membrane for recognizing naringin in aqueous media

A molecularly imprinted membrane (MIM) was prepared in aqueous media using chitosan (CS) as a functional polymer, naringin (NG) as a template molecule by phase-inversion technique. The morphologies of the MIM before and after modification with the porogen (PEG) were observed by SEM. The imprinted membrane showed an excellent performance when sulfuric acid was used as a cross-linking agent at the mass ratio of CS:NG = 15:1. The FT–IR spectra confirmed that the formation of hydrogen bond between functional polymer and template molecules. The NG–CS MIM was used to separate NG from neohesperidin/NG in the aqueous media, and the highest permeation percentage was 11.16% for 8 h.     

Fabrication of a novel cellulose acetate imprinted membrane assisted with chitosan‐wrapped multi‐walled carbon nanotubes for selective separation of salicylic acid from industrial wastewater

Highly selective cellulose acetate (CA) blend imprinted membranes for salicylic acid (SA) removal were synthesized by phase inversion technique with chitosan as a functional polymer and chitosan‐wrapped multi‐walled carbon nanotubes (CHI‐wrapped MWCNTs) as the additives. The surface and cross‐sectional morphology of membranes were strongly affected by the amount of CHI‐wrapped MWCNTs. As compared to M₁‐MIM, M₂‐MIM, and M₄‐MIM, the M₃‐MIM with 2.0 wt % CHI‐wrapped MWCNTs showed higher membrane flux, faster kinetic, binding capacity and better selectivity for SA. The experimental data of adsorption kinetic were well fitted to the pseudo‐second‐order kinetic model by multiple regression analysis. The M₃‐MIM had the maximum adsorption capacity for SA. The selectivity coefficients of SA to p‐hydroxybenzoic acid (p‐HB) and acetylsalicylic acid (ASA) over M₃‐MIM were 6.3090 and 6.0019, respectively, showing that M₃‐MIM had excellent binding affinity and selectivity for separation of SA from SA‐contained aqueous solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42654.     

Molecularly imprinted polyallylamine hydrogels: another reassessment

Researchers in the scientific community actively discuss the fact that polymer hydrogels synthesized by crosslinking polly(allylamine hydrochloride) (PAH) with epichlorohydrin (EPI) in the presence of D ‐glucose‐6‐phosphate monobarium salt do not show or show imprinting on the molecular level. In the work reported here, a polymer hydrogel was synthesized in the presence of flumequine (FQ) by crosslinking PAH with EPI in an aqueous system. The extent of FQ binding was assessed using liquid chromatography coupled with laser‐induced fluorescence detection. A hydrogel‐imprinting system was found to display FQ selectivity in binding assays (75.1 and 41.9%) compared with hydrogel formed in the absence of a template (41.6 and 20.4%). High‐magnification scanning electron microscopy (SEM) images show that both of the hydrogels are highly ordered, exhibiting a ‘honeycomb’ pattern distribution. For the effect of the template molecule in the polymer structure (i.e. the imprinting effect in hydrogel morphology), appreciable differences were observed for images obtained. The non‐imprinted polymer had a uniform, smoothly shaped surface. By contrast, the hydrogel molecular imprinting polymer surface was more globular. This difference was likely caused by the structure of the target molecule. Binding experiment results correlate with surface morphology, as analysed using SEM, and indicate that imprinted hydrogels have recognizable cavities with an affinity for used FQ from the imprint. Copyright © 2009 Society of Chemical Industry     

苯酚分子印迹聚合物及印迹膜的制备与性能研究

以苯酚为印迹分子,2-乙烯基吡啶为功能单体,采用正交试验设计,改变功能单体种类、致孔溶剂种类、交联剂用量等影响因素,分别制备了9个苯酚分子印迹聚合物（MIP1-9）,优化得到了印迹聚合物制备的最佳条件,并在此基础上制备了苯酚印迹复合膜（MIM）。对优化得到的MIP4及MIM分别进行了吸附和渗透特性研究。结果表明,实验制备的MIP4及MIM具有一定的选择性分离富集苯酚的性能。     

NH2-MIL-125(Ti)/TiO2纳米复合材料分子印迹光电化学传感器的构建及测定蔬菜中毒死蜱

以NH2-MIL-125(Ti)/TiO2纳米复合材料为载体,毒死蜱为模板分子,戊二醛为交联剂,采用电聚合的方法合成了毒死蜱分子印迹聚合物膜,并以此印迹膜构建光电化学传感器,采用电流-时间法(I-t)对蔬菜中毒死蜱进行检测,结果表明在1.0×10^-8~2.0×10^-6 mol/L浓度范围内与峰电流线性良好,相关系数为R^2=0.992 3,检测限为2.0×10^-9 mol/L,并且具有较高的选择性识别能力、良好的再生性和稳定性。方法实现了蔬菜样品中痕量毒死蜱的检测。     

Supercritical CO2-assisted preparation of a PMMA composite membrane for bisphenol A recognition in aqueous environment

This work reports a novel strategy to prepare affinity composite membranes using supercritical fluid technology. By blending molecularly imprinted polymeric particles with PMMA, a porous hybrid structure with affinity to the template molecule, bisphenol A, was prepared using a supercritical carbon dioxide (scCO₂)-assisted method. Membranes were characterized in terms of morphology, mechanical performance and transport properties. The ability of the polymers and hybrid membranes to adsorb bisphenol A was tested in aqueous solutions and fitted to a linearized Langmuir equation, showing that adsorption takes place at homogeneous affinity binding sites within the imprinted surface. Filtration experiments showed that the imprinted hybrid membrane was able to adsorb higher amounts of template even in non-equilibrium dynamic binding conditions. The hybridization of the PMMA membrane herein reported conveys two important improvements over neat PMMA membrane: it introduced molecular affinity towards the template molecule and significantly increased the permeability of the porous structures, which are key parameters in processes that involve membranes. This technique could expand the applications of polymeric beads powders and enhance the efficiency of the membrane's transport properties. Our work presents a new method to confer affinity to a porous structure by immobilization of imprinted polymers, combining polymer synthesis and membrane formation using supercritical fluid technology.     

复合型分子印迹膜的制备及影响因素

随着分子印迹技术的发展,分子印迹聚合物膜(MIM)的开发应用成为最具吸引力的课题之一。复合型分子印迹膜具有印迹分子用量少、印迹效率高、传质阻力低、高通量和可再生性质稳定等优点,对于实现MIM在分离中的应用将发挥重要作用。介绍了复合型分子印迹膜的制备方法,对影响复合型分子印迹膜的印迹效率因素进行了分析。     

Application of Molecularly Imprinted Polymer for Extraction and Determination of Nalidixic Acid by High-Performance Liquid Chromatography

Nalidixic acid imprinted polymer has high application potential in clinical purposes. Molecularly imprinted polymers were prepared using nalidixic acid as the template molecule. The polymer was synthesized in a non-covalent approach with N,N-dimethylacrilamid and allyl glycidyl ether/iminodiacetic acid as the functional monomer. The effects of various parameters such as pH and adsorption time on adsorption capacity were considered. It was confirmed that the binding ability of the prepared molecularly imprinted polymer for nalidixic acid was essentially sufficient in the presence of the other compounds coexisting in human urine.     

Fabrication and topographical analysis of non-covalently imprinted polymer inclusion membranes for the selective sensing of pinacolyl methylphosphonate—A simulant of Soman

A novel potentiometric sensor based on imprinted polymer inclusion membrane (IPIM) was developed by dispersing pinacolyl methylphosphonate (PMP) imprinted polymer materials synthesized by employing different polymerization approaches, viz. bulk, precipitation and suspension in polyvinyl chloride. The polymer materials and corresponding membranes were characterized topographically using scanning electron microscope. The effect of membrane composition, sensor performance and selectivity were studied and optimized. Such studies show that, the bulk imprinted polymer material was more selective and sensitive (with a detection limit of 4 × 10⁻⁸ M [7.2 ppb]) than suspension and precipitation material based IPIM sensors. The feasibility of the developed potentiometric sensor for trace determination of PMP in ground and tap water samples was demonstrated by both direct and standard addition methods.     

溶剂对分子印迹聚合物分子识别能力的影响：实验研究与计算量子化学分析

以茶碱为印迹分子，甲基丙烯酸为功能单体，二甲基丙烯酸乙二醇酯为交联剂，以氯仿、二甲基亚砜和四氢呋喃为溶剂，合成了分子印迹聚合物并测定了其对茶碱分子的识别能力，实验结果显示，在氯仿中合成的MIPs的分子识别性能最佳.综合Scatchard分析吸附行为、¹H NMR测定氢键以及量子化学中的密度泛函计算印迹分子和单体分子的溶剂化能等方法，研究聚合反应的溶剂体系对于印迹聚合物分子识别能力的影响及其作用机制.计算结果显示：采用与印迹分子和单体相互作用力较弱的溶剂体系所合成的印迹聚合物具有较高的分子识别性能.这与¹H NMR分析结果和吸附测定实验结果具有一致性.上述结果表明，溶剂对于分子印迹聚合物的分子识别性能具有重要的影响，而计算量子化学分析对于分子印迹介质合成时的溶剂体系选取和优化具有很好的指导作用.     

Preparation and Characterization of Imprinted Porous Materials with High Selectivity for Luteolin

In order to selectively separate luteolin from its crude solution, we synthesized imprinted porous materials with high recognition specificity for luteolin, using an imprinting technique. Modified luteolin was used as template, vinyltriethoxysilane as the functional monomer, and tetraethyl orthosilicate (TEOS) as the cross‐linking agent. The results showed the following optimum reaction conditions: The reaction ratio between luteolin and acryloyl chloride was 1 : 2 (0.10 g/0.20 g), adding 1.0 g precursor; the feasible elution time was 12 h; when the molar quantity of modified template molecule was 0.01 mol and ethenyltriethyloxy‐silane (VTEO) was 0.04 mol, the maximum yield reached 91.6 %. All samples were tested by Brunauer‐Emmett‐Teller method, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy, equilibrium adsorption experiments and selective adsorption experiments. It was found that the imprinted porous materials showed excellent selectivity for luteolin in aqueous solution. Characterization by FTIR suggested that an addition reaction had occurred between the modified template molecule and VTEO while forming ester bonds in the functional precursor. Results from pore structure analysis indicated that the imprinted porous materials had good channels, and the average pore size of the prepared porous materials was between 35.85 and 95.82 Å. Adsorption dynamics analysis suggested that, when the adsorption time reached 3 h, the adsorption process had reached balance and the adsorption capacity was at steady state. These porous materials had highly selective recognition properties and high equilibrium adsorption capacity for the template molecule. The equilibrium adsorption capacity of the imprinted porous materials to the template molecule was 11.4 times that of the blank porous materials.     

Tocopherol‐targeted membrane adsorbents prepared by hybrid molecular imprinting

A hybrid molecular imprinting technique for a tocopherol target enabled the preparation of novel membrane adsorbents. α‐Tocopherol methacrylate was used as a functional monomer, and molecular imprinted polymer (MIP) was prepared by copolymerization with divinylbenzene. After the copolymer was granulated, several hybrid molecular imprinted membranes (HMIP) containing the polymer powders were prepared by using polymer scaffolds such as polysulfone (PSf), cellulose acetate (CA), and nylon (Ny). All HMIP membranes prepared by the phase inversion technique showed selective binding of α‐tocopherol (α‐Toc) over its derivative, δ‐tocopherol (δ‐Toc). The imprint efficiencies were 0.49 for the MIP powder and 0.60, 0.64, and 0.53 for the PSf, Ny, and CA‐HMIP systems, respectively. These HMIP membranes retained their binding capacity without losing significant selectivity relative to the MIP powder. Our results demonstrated that the α‐Toc‐imprinted sites were responsible for the selective binding of the target molecules by the HMIP membranes. The membranes' binding behavior was analyzed using Scatchard plots; a heterogeneous distribution of binding sites was observed in both the MIP polymer and HMIP membranes. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

奎宁印迹聚合物的吸附与识别特性的研究

以奎宁为模板分子 ,利用分子印迹技术合成了一种新型的类似于人工受体的印迹聚合物 ,研究了它对奎宁和其它底物的吸附特性和选择性识别能力 ,并对其固相萃取性能做了初步的研究。     

壳聚糖表面胰蛋白酶分子印迹聚合物的制备及性能的研究

在壳聚糖表面通过希夫碱反应嫁接一层戊二醛,形成核-壳结构微球。然后在这个核-壳微球上,以胰蛋白酶为模板分子,3-氨基苯硼酸为功能单体,制备了胰蛋白酶分子印迹聚合物,通过静态吸附法,研究了聚合物的吸附性能。结果表明,印迹聚合物对模板分子有较高吸附容量和特异选择性。为从蛋白质混和溶液中分离富集胰蛋白酶提供了新的材料和方法。     

山奈酚分子印迹聚合物的制备及其性能表征

采用分子印迹技术,以山奈酚(Kaempferol,KAE)为模板分子,2-乙烯基吡啶(2-Vpy)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,合成了山奈酚分子印迹聚合物(KAE-MIP)。采用静态平衡结合实验评价了KAE-MIP对底物分子的结合特性,并进行了吸附动力学研究。结果表明,KAE-MIP对KAE呈现出了很高的选择吸附特性;Scatchard分析显示KAE-MIP对KAE存在不同亲和力的两类结合位点;与对照物在KAE-MIP上的吸附行为比较表明,KAE-MIP对KAE具有良好的分子识别性能;KAE-MIP对KAE的选择性吸附基本在2 h之内完成。     

Three-level response surface full-factorial design: advanced chemometric approach for optimizing diclofenac sodium-imprinted polymer

The present research work was undertaken to optimize the template:monomer:cross-linker ratio of the diclofenac sodium block molecularly imprinted polymer with respect to the molecular recognition properties. A three-level full-factorial design was employed. This is of great interest because applying this approach instead of traditional methods would be expected to improve validation of the optimum and consumed time. Imprinted polymers with selected ratios and the control polymers were synthesized by precipitation polymerization method and the values of rebind capacity and imprinting factor calculated after performing batch rebinding experiments. The predicted optimum ratios of (1:8:40) and (1:4:40) were found by applying the three-dimensional surface plots for rebind capacity and imprinting factor. The optimized imprinted polymers and their control polymers were produced. These polymers were evaluated using equilibrium binding experiments and finally the optimum molar ratio of (1:8:40) chosen. Batch rebinding experiments were carried out to evaluate the binding and selectivity properties of the optimized polymer. A heterogeneous nature of the binding sites was found based on the Scatchard plot. The selectivity study of imprinted polymers demonstrated a 24 % cross-reactivity towards meclofenamate sodium, but less than 2 % towards fenoprofen calcium.