Synthesis And Properties Of Bisphenol A Molecularly Imprinted Polymers And Molecularly Imprinted Catalysts

Bisphenol A?BPA?has estrogen-like effect to cause endocrine disorders and increase the risk of cancer.As important organic chemical raw materials,BPA is widely founded in plastic products and industrial waste water to be harmful to mankind.At present,physical adsorption and Fenton oxidation are the main methods to remove bisphenol A.However,these methods are not selective and cannot specifically remove bisphenol A.Therefore,looking for selective adsorbents and catalysts to specifically remove bisphenol A is the constant pursuit for scientific research workers.Molecularly imprinted polymers?MIPs?have good selectivity for template molecules because they contain the pores matching the molecular structure of template.Molecularly imprinted polymers have many advantages of simple preparation process,good mechanical stability and high reusing rate,and they can be used as specific adsorption agent for template molecules.The molecular imprinting catalysts based on molecular imprinting also have high selectivity for template molecules,and they can be used as selective catalysis.Three kinds of bisphenol A molecularly imprinted polymers and non-imprinted polymers?NIPs?were prepared by molecular imprinting technique with bisphenol A as template molecule,chloroform as solvent,azobisisobutyronitrile as initiator,acrylamide?AM?or methacrylic acid?MAA?as functional monomer,divinylbenzene?DVB?or trimethylolpropane trimethacrylate?TRIM?as crosslinking agent.The composition of polymers were MIP1/NIP1?AM/DVB?,MIP1/NIP2?MAA/DVB?and MIP3/NIP3?AM/TRIM?.The effects of functional monomer and cross-linker on the adsorption properties of polymers were discussed by static adsorption kinetics experiments.The best adsorption capacity for BPA was determined on MIP1 in aqueous phase,and the equilibrium adsorption capacity was 927.32?mol/g with BPA initial concentration of 1mmol/L.The adsorption behaviors of MIPs and NIPs in aqueous solution were analyzed by Lagergren's kinetic model.The adsorptionbehaviors of various MIPs and NIPs were in good agreement with Lagergren's pseudo-second-order kinetics model and did not accord with Lagergren's pseudoi-first-order kinetics model.MIP1 and NIP1 were characterized by FT-IR,scanning electron microscopy.The results show that MIP1 have rougher surface,larger specific surface area and pore volume than those of NIP1.The static adsorption equilibrium experiment and Scatchard model indicate that the equilibrium adsorption constant?K_B?and the maximum apparent adsorption capacity(Q_max)of MIP1 are106.01L/mmol and 266.66?mol/g in low concentration of BPA aqueous solution,while those are 14.27L/mmol and 1236.88?mol/g in high concentration of BPA aqueous solution at 298 K,respectively.The selective experiment shows that the selectivity of MIP1 for BPA is much higher than that for phenol with phenol as contrast,and the selectivity factor I is 1.43 to indicate that the prepared MIP1 has better selectivity for BPA.The reusability of MIP1 was studied by repeated experiments.Used for three times,the polymers adsorption capacity is 97.07% of the initial adsorption capacity,while that is only 91.67% for five times.The reasonable reusing time is suggested for three times.Based on the adsorption research results of molecularly imprinted polymers,the selective catalytic performance of molecularly imprinted polymer catalysts with silver nanoparticles?AgNPs?was also investigated.Molecular imprinted catalyst of MIPs-AgNPs was prepared with bisphenol A as template molecule and substrate molecule,acrylamide as functional monomer and silver nanoparticle as catalytic active center.The polymer catalysts of NIPs,MIPs and NIPs-AgNPs were prepared under the same experimental conditions.The molecularly imprinted catalysts were characterized by scanning electron microscopy?SEM?and transmission electron microscopy?TEM?.The catalytic performance of the molecular imprinted catalysts was studied by the oxidation reaction of bisphenol A.The results show that the catalyst of MIPs-AgNPs has the best catalytic effect.When the reaction time is four hours,the conversion of bisphenol A reaches 78.6%.The selective catalytic performance of MIPs-AgNPs was studied with tetrabromobisphenol A as contrasting substrate molecule.The conversion of tetrabromobisphenol A is only 50.7%,whichindicates that MIPs-AgNPs has selectively catalytic effect to the template molecule of bisphenol A.