Preparation Of Hollow/Core-shell Structure Affinity Adsorbent And Its Selective Separation Of Luteolin

Luteolin?LTL?is an important natural flavonoid widely distributed in plant materials,its bioactivities have attracted great interest and been extensively studied in the recent years,due to the applications in many fields,such as antioxidant,anti-inflammatory,antibacterial,vasodilation,and cancer prevention,etc.Nowadays,core/shell or hollow microspheres microspheres with tailored functional polymer shell have attracted much attention in the field of separation and adsorption due to their high density of surface functional groups and easy modification nature.Metal ion?Zn?II??or boric acid group can combine with the cis-diol group to form an reversible covalent bonding,further the structure of LTL contains the cis-diol.We combined these above merits to synthesis the Fe₃O₄@PVIM@Zn?II?,Ho-SnO₂@MIPs and H-PAVM,then the adsorption ability of the materials was explored through a series of adsorption experiments.The main contents are summarized as follows:?1?Magnetic microspheres?Fe₃O₄@PVIM@Zn?II??composed of a high magnetic-response Fe₃O₄ core and a Zn?II?-immobilized cross-linked polyvinyl imidazole?PVIM?shell via reflux-precipitation polymerization and metal-ion affinity strategy were fabricated.Integration of the advantages of specific uptake and fast separation,Fe₃O₄@PVIM@Zn?II?was adopted as an ideal pathway for luteolin?LTL?recognition.As-prepared Fe₃O₄@PVIM@Zn?II?possessed core-shell structure,uniform size,and very easy synthesis process.The batch mode experiments can be well described by Pseudo-first-order kinetic models and Langmuir isotherm,the quick binding equilibrium?within 45 min?and large monolayer adsorption capacity(23.92 mg g^-1)at 298 K were also observed.In addition,Fe₃O₄@PVIM@Zn?II?displayed remarkable selectivity to LTL,and the purification process using Fe₃O₄@PVIM@Zn?II?can make LTL purified from 85%to94.26%approximately.The antibacterial activity of purified LTL was outstanding by means of staphylococcus cureus?ATCC29213?resistance experiment.?2?Molecular imprinted hollow SnO₂ microspheres?Ho-SnO₂@MIPs?integrated with boronate affinity ability were fabricated via atom transfer radical polymerization?ATRP?,and then they were adopted as ideal adsorbents for cis-diol containing luteolin?LTL?recognition and separation.Ho-SnO₂@MIPs possessed uniform size,porous and hollow structure,appropriate BET surface area(118.6 m² g^-1),and high-density boronate affinity sites(0.22 mg m^-2),endowing them highly specific uptake and fast separation properties.Due to the merit of pH responsive boronate affinity,the reversible interaction of boronic acid groups and LTL was regulated by the pH value facilely,which was benefit for the controlled recognition and release.In the batch mode experiments,the quick binding equilibrium?within 60 min?and a rather high specific binding capacity(33.65 mg g^-1)at298 K were observed,and Ho-SnO₂@MIPs also displayed high rebinding selectivity to LTL.By a purification process,a commercially available LTL with 85%purity could be easily extracted and concentrated to 95.28%purity by Ho-SnO₂@MIPs,and the purified products possessed the similar antibacterial performance with standard substance.?3?Double sided molecular imprinted hollow polymer with single-hole microspheres?H-PAVM?integrated with boronate affinityability were fabricatedvia distillation-precipitation polymerization?DPP?.The formation mechanism of hole that is based on the concomitant microphase separation and symmetrical volume shrinkage of shell materials provides a reproducible approach for creating holes in polymer shells.Then,they were adopted as ideal adsorbents for cis-diol containing luteolin?LTL?recognition and separation due to the reversible covalent bonds with the cis-diols groups of LTL.H-PAVM possessed uniform siz,single hole and hollow structure,and high-density boronate affinity sites(0.27 mg m^-2),endowing them highly specific uptake and fast separation properties.In the batch mode experiments,the quick binding equilibrium?within 100 min?and a rather high specific binding capacity(46.96 mg g^-1)at 298 K were observed.By a purification process,a commercially available LTL with 85%purity could be easily extracted and concentrated to 95.88%purity by H-PAVM,and the purified products possessed the similar antibacterial performance with standard substance.