Synthesis Of Water-compatible Molecularly Imprinted Polymers And Their Application In The Treatment Of Wastewater

The development of new methods and materials, which treated with toxic andprecious substances in wastewater, has become a hotspot in the field of waterpollution control. For it’s outstanding selectivity, molecularly imprintedpolymers(MIPs) has gradually become an important means of wastewater treatment.However, there is technical difficulty in developping a methods with high selectivity,big adsorption capacity, and strong hydrophilic according to the real wastewatersample.The wastewater of water-soluble acid dyes and heavy metal ions are seriouslyharmful to human. However, the synthesis of molecularly imprinted polymers withtraditional method shows poor selectivity and adsorption capacity. A specific andhydrophilic molecularly imprinted polymers was developed in order to solve aboveproblems, and it’s recognition characteristics and binding mechanism of the polymerswere also investigated. Finally, we preliminary studied it’s ability of removing andrecovering water-soluble acid dyes and heavy metal ions in real wastewater samples.The details are summarized as follows:1. The traditional functional monomer mainly provides the hydrogen-bondingaction, and shows poor hydrophilicity. We designed a new ionic liquid functionalmonomer which has π-π hydrophobic, hydrogen-bonding and electrostatic interactionswith template molecule.1-(α-methyl acrylate)-3-methylimidazoliumbromide(1-MA-3MI-Br) was synthesized through carbon negation ion reaction,halogonation reaction and ion reaction, using diethylmathonate as starting material.The chemical of1-MA-3MI-Br structure was confirmed by1H NMR and IR analysis.2. In recently, MIPs were synthesized with traditional functional monomer, andshowed poor selectivity and adsorption capacity for target molecule in aqueoussolution. Novel water-compatible MIPs were synthesized in methanol-water systemswith tratarzine as template and1-MA-3MI-Br as functional monomer. The hydrophilicmolecularly imprinted solid phase extraction(MISPE) conditions were optimized.1-MA-3MI-Br-MISPE were used as selective sorbents for the solid-phase extractionof water-soluble acid dyes from wastewater and soft drink. The good linearity of themethod was obtained in a range of0.5-100μg/mL with the correlation coefficient of>0.999. The mean recoveries for the acid dyes are higher than89.1%in spiked wastewater and91.0%in spiked soft drink. The detection limits were in a range of0.13-0.51μg/L for the water-soluble acid dyes in wastewater and0.095-0.84μg/L forthose in soft drink. Compared with other MIPs which were prepared with methylacrylate or4-vinyl pyridine as functional monomers, the1-MA-3MI-Br-MIPs showedhigher ability of recovery and selectivity. Moreover, compared with strongly anionexchange solid phase extraction, mixture anion exchange solid phase extraction, and1-MA-3MI-Br-non-imprinted solid phase extraction, almost all of the matrixinterferences were removed by1-MA-3MI-Br-MISPE, exhibiting higher selectivity,recovery and enrichment ability for water-soluble acid dyes and better baselines in theresults of HPLC analysis.3. The application of above MIPs needs a very complicated procedure such asfiltration or centrifugation. Novel magnetic and hydrophilic molecularly imprintedpolymers (mag-MIPs) were prepared by an inverse emulsion-suspensionpolymerization to remove water-soluble acid dyes from contaminated water with1-(α-methyl acrylate)-3-methylimidazolium bromide (1-MA-3MI-Br) being utilized asa new functional monomer. The magnetic polymers showed high chemical stability,excellent reproducibility, and good magnetic property. Moreover, effect ofconcentration and pH value of water-soluble acid dye solutions were optimized.Compared with the methyl acrylic acid and4-vinylpyridine modified mag-MIPs, the1-MA-3MI-Br-mag-MIPs showed stronger removal efficiency. Meanwhile, the1-MA-3MI-Br-mag-MIPs removal efficiency are more than90%for water-solubleacid dyes in different water samples. Compared with strongly anion exchange solidphase extraction, the1-MA-3MI-Br-mag-MIPs showed better concentration andpurification effect, higher purity. Consequently, the1-MA-3MI-Br-mag-MIPs showeda promising potential in recycling the acid dyes from wastewater conveniently.4. Up to date, these ion imprinted polymers were mainly prepared via bulkpolymerization, precipitation polymerization, and suspension polymerization. Theseimprinting techniques show low adsorption capacity and poor site accessibility totarget ions, because ions are embedded deeply into polymers, and the application ofthese ion imprinted polymers is a very complicated procedure which needs filtrationor centrifugation. In the paper, the two kinds magnetic ion imprinted polymers wereprepared on the surface of Fe3O4and Fe3O4@SiO2by surface imprinting techniquecombined with a sol-gel process. The two kinds of magnetic ion imprinted polymersshowed high chemical stability, good magnetic property, fast adsorption kinetics. The adsorption efficiency was investigated by static and dynamic adsorption experiment.These magnetic polymers were applied to remove and recover heavy metal ions in realwastewater samples and get good results. The new surface magnetic ion imprintedpolymers maybe provide a reliable and effective solution to recover and utilizeprecious heavy metal from industrial wastewater.