Study On Porous Material Based On Emulsion Templating With Boric Acid For Selective Extraction And Separation Of Luteolin

With the continuous improvement of the global medical,natural medicine has been paid more and more attention in the world because of its low side effects,environmental protection,safety and effectiveness.Among herbal medicines,luteolin?LTL?is a weakly acidic flavone molecule containing the structure of cis-hydroxyl,and has antitussive,expectorant and anti-inflammatory effect in clinic,moreover,it has an antibacterial,antiviral and lowering cholesterol effects in the human body,which is a kind of edible medicinal materials with great development potential.Nowadays,the porous materials prepared by emulsion template method are widely used in the field of separation and adsorption.Boric acid is a material that can combine with the cis-diol group to form a reversible covalent bonding.Because the structure of LTL contain the cis-diol,we combined the two techniques to synthesis the MPs-BA,PGM-Pickering-BN and BSP,then we explored the adsorption ability of the materials through a series of adsorption experiments.The main contents are summarized as follows:?1?Macroporous polymers with boronate affinity ability?MPs-BA-1?were prepared via high internal polymer emulsion?HIPEs?template and applied to selective adsorption a natural favonoid luteolin?LTL?.As-prepared MPs-BA-1 possessed macroporous polymer network and accessible binding sites for cis-diols,and then its adsorption behaviors were studied using static and dynamic methods.The conclusion showed that MPs-BA-1 served the specific adsorption towards LTL and adsorbed quickly.Dynamic adsorption incorporated with the analysis of response surface methodology?RSM?suggested that the optimal adsorption amount(73.47 ?mol·g^-1)achieved when the flow rate of LTL solution was 3.0 mL·min^-1,temperature was 28.28 oC and concentration of LTL solution was 30mg·L-1.MPs-BA-1 retained the adsorption amounts for successive cycles,but the loss using dynamic method was larger than in the batch method.?2?In this work,a water-in-oil?W/O?Pickering HIPEs template stabilized by boronic acid suspended mesoporous silica nanoparticles?BA-MSNs?was applied to prepare macroporous poly?glycidyl methacrylate??PGM-Pickering-0.10?,and then B-N coordination complex resulted from the reaction of m-aminophenylboronic acid?APBA?and 1,6-hexamethylenediamine was integrated to the PGM-Pickering via post functionalization.Subsequently,as-prepared PGM-Pickering-0.10-BN was called“Wulff-type boronic acids”.Then,functionalized PGM-Pickering by B-N coordinated complex?PGM-Pickering-BN?was adopted to capture LTL,and the separation behaviorswere evaluated by batch and dynamic adsorption experiments.In the static adsorption,the pH-dependent adsorption experiments demonstrated that PGM-Pickering-0.10-BN was able to capture LTL(158.5 ?mol·g^-1 at 298K)and fast binding kinetics under neutral condition,while macroporous polymers without post functionalization or functionalized with APBA possessed poor adsorption performance(2.358 ?mol·g^-1)at pH =7.0.The selective research showed the integrated B-N coordination complex did play vital roles in the specific adsorption enhancement of LTL.By optimizing dynamic adsorption factors with response surface methodology?RSM?,the maximum adsorption amount of 177.78 ?mol·g^-1 was achieved under neutral condition.?3?The Pickering O/W emulsion with the 4-vinylphenylboronic acid in the oil phase was stabilized by the emulsifier and B-CNT@ D-Fe₃O₄ particle,which is assembled by the dopamine-modified Fe₃O₄ nanoparticles?D-Fe₃O₄?and carbon nanotubes modified by the boric acid?B-CNT?.Then the porous microspheres?BSP-1 ? BSP-2 and BSP-3?were polymerized by the emulsion to adsorb LTL.The results of adsorption experiments showed that the adsorption capability of BSP-1 reached 53.12 ?mol·g^-1 and the BSP showed favorable selectivity toward LTL molecule.Dynamic adsorption incorporated with the analysis of response surface methodology?RSM?suggested that the optimal adsorption amount(145 ?mol·g^-1)achieved when the flow rate of LTL solution was 1.0 mL·min^-1,temperature was 35 oC and concentration of LTL solution was 25 mg·L-1.After the six adsorption/desorption cycle,the BSP still has a good adsorption capability with 95% of original adsorption amount.