Preparation Of Molecularly Imprinted Nanocomposite Membranes Based On Spherical Nano Filler For Separation Of Phenylethanol Glycoside

Cistanche tubulosa is a perennial parasitic plant of the genus Cistanche of the Orobaceae,which is edible and has medicinal value for nourishing.Research shows that it has many pharmacological effects,such as anti dementia,anti-aging,anti fatigue,and regulating immune function.Currently,it is still difficult to develop a method that can efficiently isolate phenylethanolamine glycosides(Ph Gs)from Cistanche tubulosa.Molecularly imprinted membranes can specifically select and recognize template molecules from complex systems.Therefore,in this thesis,a series of different molecularly imprinted composite membranes were designed and prepared by blending different nanofillers with PVDF membrane substrates for the separation of Ph Gs.By regulating the imprinted sites and imprinted cavities,the efficient separation of Ph Gs by the membrane was further enhanced.The main research results are as follows:(1)Design and Preparation of molecularly imprinted nanocomposite membranes(HMINMs)based on hollow polymer nanospheres(HPN): The synthesized PCMSs@PEI was doped into the PVDF matrix by Pickering emulsion polymerization,and the PMINMs prepared by ACT imprinting layer were synthesized on the surface of PCMSs@PEI@PVDF membrane by a two-step temperature control method for selective separation of ACT from Ph Gs.The results showed that HMINMs exhibited excellent selective separation performance for ACT,with an adsorption capacity of 104.90 mg/g,adsorption selectivity of 4.41,and osmotic selectivity of 7.84.This is mainly due to the fact that the hydroxyl groups on the surface of HPN can affinity ACT,improve the adsorption capacity of HMINMs for ACT,and that the larger cavity structure and specific surface area of HPN can accommodate ACT molecules.In addition,after 10adsorption-desorption cycles,the adsorption capacity of HMINMs can still maintain above 91.04% of the original adsorption capacity.(2)Molecularly Imprinted nanocomposite membranes(PMINMs)designed and prepared by PEI-functionalized porous polymer Nanospheres Based on one-shell Multi-core Morphology(PCMSs@PEI): The synthesized PCMSs@PEI was doped into the PVDF matrix by Pickering emulsion polymerization,and the PMINMs prepared by ACT imprinting layer were synthesized on the surface of PCMSs@PEI@PVDF membrane by a two-step temperature control method for selective separation of ACT from Ph Gs.The results showed that PMINMs showed excellent selectivity for ACT separation,with adsorption capacity of 110.95 mg/g,adsorption selectivity of 5.15,and permeability selectivity of 10.04.This is mainly attributable to: PCMSs@PEI with a shell multi-core morphology has a large cavity and abundant pore structure,which not only increases the adsorption space of ACT,but also increases the internal transfer path of ACT to PCMSs@PEI.Moreover,the introduction of PEI strengthens the affinity of PCMSs@PEI to ACT.The selective adsorption of PMINMs to ACT was improved.The isothermal adsorption and adsorption kinetics indicate that the adsorption process of PMINMs is monolayer adsorption,and the adsorption process conforms to pseudo-second-order kinetics.The permeability selectivity experiment showed that the separation process of ACT by PMINMs was consistent with the delayed permeability mechanism.(3)Design and preparation of molecular-imprinted nanocomposite membranes(EMINMs)based on egg yolk shell magnetic mesoporous carbon nanospheres(EMMHC): The EMMHCs were filled into the PVDF matrix,and the EMINMs prepared by ACT imprinting layer were synthesized by in situ polymerization on the surface of EMMHC@PVDF membrane for selective separation of ACT from Ph Gs.The results showed that EMINMs exhibited excellent selective separation performance for ACT,with an adsorption capacity of 120.48 mg/g and an adsorption selectivity of 7.52.This is mainly due to the fact that EMMHC has a large internal cavity structure and specific surface area,which improves the adsorption space for ACT,and EMMHC can utilize the magnetic conductivity effect to expose EMMHC nanospheres to more EMMHC@PVDF The membrane surface can increase the imprinting sites and imprinting cavities for EMINMs,thereby improving the selectivity of EMINMs to ACT.The permeation selectivity experiment shows that the separation process of EMINMs for ACT conforms to the delayed permeation mechanism,and the permeation selectivity of EMINMs can reach 14.28.