Preparation Of Boronate Affinity High Recognition Composites And Study On Behavior And Mechanism Of Selective Separation And Purification Of Luteolin

Peanut shell is a common agricultural solid waste from peanut cultivation,and there was about 5.0 million metric tons are produced annually in China.In addition to a small part using as animal feed,most of them are directly throw it away or burning utilization,resulting serious waste of resources and economic losses.So far,the recycling of peanut shell still remain a re search focus and difficult point in the field of environmental science and engineering.Luteolin（3’,4’,5,7-tetrahydroxyflavone,LTL）,as a typical diol structure containing flavone molecule with excellent antioxidant potential,anti-inflammatory,anti-cancer,antidiabetics,enhance immunity ability.It has very high medical value.According to the literature,peanut shell residue is one of the raw materials with the highest LTL content.Therefore,it has a very important scientific,social and economic value to construct a new method for efficient separation and purification from peanut shell residue.Boronate affinity is an important tool for the separation and enrichment of a o-dihydroxyl structure,which can achieve the binding and release by adujusting pH value.Therefore,it is expected to be used for the separation and purification of LTL.However,the traditional boronate-based composites still remain some great challenge,for the difficulty in nano-size particles recovery,poor mechanical properties,and and the inability to specific recognize target o-dihydroxyl molecules,which limit its further application.This paper focuses on selective separation and purification from peanut shell waste residue,three different types of boronate-based composites were prepared and study on behavior and mechanism of selective separation of luteolin recognition and separation of LTL.The main syudy contents of this thesis are as follows:1.The preparation of boronate-based metal-organic frameworks composites for highly selective separation and purification of LTL（1）Multiple assembly strategy is used to prepare magnetic metal-organic framework composite（Fe₃O₄@PDA@BA-MOFs）for highly selective separation and enrichment of LTL.The well-known solvothermal reaction was adopted to prepare the magnetic matrix Fe₃O₄,followed by self-polymerization of dopamine,to create the polydopamine（PDA）onto Fe₃O₄ and then Zn²⁺was easily adhered to the surface of dopamine shell.The Fe₃O₄@PDA@BA-MOFs were fabricated between Zn²⁺and organic ligands by multiple assembly strategy.The obtained Fe₃O₄@PDA@BA-MOFs have a high specific surface area,uniform shape,high saturation magnetization,good hydrophilicity.Comapared with Fe₃O₄@PDA@MOFs,Fe₃O₄@PDA@BA-MOFs have enhanced the binding properties and adsorption selectivity to LTL due to the introduction of boronic acid.Based on the static adsorption experiments,Fe₃O₄@PDA@BA-MOFs showed high selectivity,obvious binding kinetics,large adsorption capacity and excellent reusability（above 91.23%at least six repeated adsorption-desorption cycles）,which could reach adsorption equilibrium at 360 min and the corresponding maximum adsorption capacity for LTL was 32.72 mg/g.（2）The polyurethane sponge/graphite oxide/boronate-based metal-organic framework（PU/GO/BA-MOFs）was fabricated by a three-in-one strategy,and then used for selective separation and enrichment LTL.Firstly,BA-MOFs was introduced on the surface of GO.Under the mechanical agitation,GO/BA-MOFs was adhered to the surface of polyurethane foam.The obtained PU/GO/BA-MOFs were used for specific separation and enrichment of LTL.The PU sponge possessed the advantages of convenient adsorption-desorption process owing to its reversible‘‘shape memory”effect.In addition,PU/GO/BA-MOFs can attain the adsorption capacity towards LTL six times than non-o-dihydroxyl structure.Subsequently,peanut shell coarse extract（85%LTL）was twice purified by PU/GO/BA-MOFs was successfully evaluated.Purified LTL（second time）have exhibited more excellent antibacterial effect and more purity.The antibacterial properties of the purified product reached about 98%,showing obvious antibacterial properties.The PU/GO/BA-MOFs shows an excellent reusability（above 91.23%at least five repeated adsorption-desorption cycles）.（3）Herein,we demonstrated a facile interface-induced Zn（II）-ligand-fragment co-assembly method to in situ fabricate boronate-based MOF membrane on carbon framework for specific separation and purification of LTL in aqueous phase.Compared with the separated MOF particles and carbon framework,the obtained BA-MOFs-PFCS exhibited similar adsorption kinetics performance but higher adsorption capacity in static separation.Dynamic separation study also suggested that the MOF composite could achieve an excellent adsorption capacity（31mg/g）under desired separation environment.As a proof of this concept,the 85%LTL was used to separation and purification.Purified LTL have exhibited similar antibacterial effect with standard sample.The antibacterial properties of the purified product reached about 99.90%,showing obvious antibacterial properties.2.Synthesis of molecularly imprinted polymers with double recognition abilities and for highly efficient separation and purification of LTL（1）A two-step consecutive atom transfers radical polymerization（ATRP）is used to fabricate the molecular imprinted polymer（DM-MIPs）with double recognition sites for specific separation and purification of LTL.First,Zn²⁺-supported poly（vinyl imidazole）（PVLD）shell based on the HNTs via the first ATRP is prepared to separate LTL by metal chelating.Then the surface of HNTs are introduced using low pKa boronic acid monomer（AMC-FPBA）by the second ATRP.Taking advantage of low pKa of DM-MIPs and double recognition sites,DM-MIPs possess a desired binding with LTL under neutral condition.In static adsorption,DM-MIPs show large LTL loading amount（83.42 mg/g）at pH=7.0.As a proof of this concept,purified LTL can be easily separted and purified,and the purified product exhibits the similar antibacterial performance with standard sample.The antibacterial properties of the purified product reached about 98.42%.（2）Molecular imprinted polymer（DR-MIPs）with double recognition sites was prepared by one step atomic radical polymerization（ATRP）and for highly efficient separation and purification of LTL.The two-dimensional（2D）structure of GO have selected as substrate material due to the high surface area and recognizing sites of GO.4-vinyl phenylboronic acid（4-VBA）and methacrylic acid（MAA）were selected as covalent and non-covalent imprinted monomers,and then were polymerized on the surface of GO by ATRP,respectively.The kinetic experiment results showed that the adsorption capacity of DR-MIPs was up to 56.27 mg/g in 30 min at 298 K owing to the enough imprinted sites with double recognition abilities.In addition,the antibacterial properties of the purified product reached about 93.47%,showing obvious antibacterial properties.3.Synthesis of porous boronate affinity molecular imprinted polymer and for highly efficient separation and purification of LTL（1）A hydrophilic porous molecular imprinted polymer（H-UIO-66-NH₂-IHIPEs）was constructed via HIPEs emulsion template method,which can be embedded into the hydrogel skeleton as a physical skeleton.The oil phase monomer:octadecyl methacrylate（SMA）monomer and glycidyl methacrylate（MAA）monomer.The water monomers:N,N-dimethyl acrylamide（DMA）and water-soluble phenylboronic acid monomer（H-BA）,then vigorously stirred and polymerized under UV light.In order to obtain hydrophilic surface,the ethanolamine was introduced on the surface by grafting methods.The adsorption kinetics,isotherm,selectivity and regeneration of H-UIO-66-NH₂-IHIPEs for LTL were investigated.Compared with the H-UIO-66-NH₂-NIHIPEs,the obtained H-UIO-66-NH₂-IHIPEs exhibited similar adsorption kinetics performance but higher adsorption capacity in static separation,and the adsorption capacity of LTL could reach 89.56%within 60 min.Meanwhile,the regeneration experiment shows the good reusability（the five repeated adsorption and desorption cycles should be at least 91.39%or above）.In addition,crude peanut shell extract（85%LTL）was separated and purified by H-UIO-66-NH₂-IHIPEs,and the purified product reached about 97.5%.（2）The single Pickering emulsion template method to construct flexible molecularly imprinted polymers（UIO-66-NH₂@MIPs-FPS）for highly efficient separation and purification of LTL.By means of gentle oxidation crosslinking polymerization,poly-3-aminobenzboric acid can be formed on the surface of UIO-66-NH₂ as the imprinting layer.Additionally,the single Pickering emulsion was stablized by using UIO-66-NH₂@MIPs as hydrophilic stabilized particle and surfactant 2296.Using methoxyethyl acrylate（MEA）as hydrophobic monomer and N-（methoxymethyl）methylacrylamide（MMP）as hydrophilic monomer,and UIO-66-NH₂@MIPs-FPS was obtained by stirring and polymerization.According to the static adsorption experiment,UIO-66-NH₂@MIPs-FPS has higher adsorption capacity,faster adsorption rate and better selective recognition ability than UIO-66-NH₂@NIPs-FPS due to the presence of boronic acid recognition sites and imprinted cavities,and the adsorption capacity of LTL can reach 97.68%within 80min owing to the excellent rapid swelling ability.Meanwhile,the regeneration experiment shows the good reusability（the five times repeated adsorption-desorption cycle was at least 92.77%）.85%LTL was separated and purified by UIO-66-NH₂@MIPs-FPS,and the purified product reached about 97.1%...