Study On The Preparation And Performance Of Three Functional Molecular Imprinted Materials

Molecular imprinting technology(MIT)is usually described as a technical method for making molecular locks(molecular imprinted polymers)to match molecular keys(template molecules),due to its unique structural predictability and specific recognition,it was widely used in various fields.Because the adsorption and binding sites of molecular imprinted polymers(MIPs)have strong complementary with template molecules in shape,size and functional groups,they have high selective adsorption properties for template molecules.The paper have modified the preparation method of MIPs to make it have higher selective adsorption and other auxiliary properties.Take MIPs as main material,the aminated carbon nanotubes were introduced to prepare aminated carbon nanotubes grafted methylene blue molecular imprinted polymers(CNT-MB-MIPs),which can inhibit the adsorption of iron ions while adsorbing methylene blue.Nano calcium carbonate reacts with part of acrylic acid to prepare calcium acrylate-acrylic acid copolymer methylene blue molecular imprinted polymers(Ca CO₃-MB-MIPs),which can inhibit the adsorption of copper ions while adsorbing methylene blue(MB);Photoresponsive methylene blue molecular imprinted polymers(P-MB-MIPs)were prepared by the introduction of p-aminoazobenzene,which made P-MB-MIPs have photosensitive properties.1.Aminated carbon nanotubes grafted methylene blue molecular imprinted polymers(CNT-MB-MIPs).Aminated carbon nanotubes are grafted with part of acrylic acid,and acrylic acid were heated and polymerized under the action of template molecules,functional monomers,cross-linking agents,and initiators to form gel-like imprinted polymers.The polymer materials were characterized by scanning electron microscopy(SEM),Fourier infrared spectroscopy(FTIR),photoelectron spectroscopy(XPS),X-ray diffraction(XRD)and thermogravimetric analysis(TGA).Experiments have found that when the initial MB concentration is 12 g L^-1,the adsorption capacity of CNT-MB-MIPs to MB can reach 2793 mg g^-1,which is higher than that of MB-MIPs.At the same time,compared with MB-MIPs,we found that the adsorption capacity of CNT-MB-MIPs for iron ion is lower,indicating that CNT-MB-MIPs can inhibit the adsorption of iron ions.Adsorption kinetics study showed that the adsorption mechanism of the polymer for methylene blue was in good agreement with the quasi-second-order kinetics model,and the adsorption mechanism for iron ion was in good agreement with the Bangham kinetics model.The adsorption isotherm showed that the adsorption process of the two adsorbents were mainly monolayer chemical adsorption.2.Calcium acrylate-acrylic acid copolymer methylene blue molecular imprinted polymers(Ca CO₃-MB-MIPs):Nano calcium carbonate reacts with part of acrylic acid to generate calcium acrylate,carbon dioxide and water,and were heated and polymerized with acrylic acid under the action of functional monomers,crosslinkers,initiators,etc.to form a milky white gel-like polymer.The polymer materials were characterized by SEM,FTIR,XPS,XRD and TGA.Experiments have found that when the initial MB concentration is 12 g L^-1,the adsorption capacity of Ca CO₃-MB-MIPs on MB can reach 2631 mg g^-1,which is higher than that of MB-MIPs.The study of adsorption kinetics found that the adsorption mechanism of this polymer for methylene blue was in good agreement with the Bangham kinetic model.It was also found that compared with MB-MIPs,this polymer could inhibit the adsorption of copper ions,and the adsorption process were in good agreement with Bangham kinetic model,and the adsorption isotherm indicated the adsorption processes of the molecular imprinted polymer on the two adsorbates are mainly a single-layer chemical adsorption.3.Light-responsive methylene blue molecular imprinted polymers(P-MB-MIPs):Acrylic acid and thionyl chloride are used as raw materials to synthesize acryloyl chloride,and then the condensation reaction with p-aminoazobenzene is used to prepare light-responsive monomers.This monomer is copolymerized with acrylic acid to form a light-responsive methylene blue molecular imprinted polymer.The polymer materials were characterized by SEM,FTIR,XPS,XRD and TGA.The experimental results showed that the adsorption capacity of P-MB-MIPs on MB under sunlight irradiation was three times than under UV irradiation.The rod-like structure of p-aminoazobenzene became curved rod-like after ultraviolet light,which caused the polymer structure to shrink,and part of the methylene blue was released,so the polymer's absorption of methylene blue under ultraviolet light is lower than that under sunlight.The study of adsorption kinetics found that the adsorption of methylene blue by P-MB-MIPs fitted well with the Elovich kinetic model,and the adsorption isotherm model showed that the adsorption process was mainly a single-layer chemical adsorption.