Synthesis And Modification Of Porous Cyclodextrin Polymers And Their Applications In Separation And Enrichment

?-Cyclodextrin(?-CD)is widely used because of its unique properties of"hydrophobic internal cavity and hydrophilic external surface".The hydrophobic internal cavity can be embedded with guest compounds to form complexes through host-guest interactions.On the external surface of ?-CD,the hydroxyl groups make CD hydrophilic,thus result in hydrophilic interaction with hydrophilic guest molecules.The hydroxyl groups on the surface are easily modified,which is of great significance to supermolecular chemistry.In addition,?-CD is a cheap and non-toxic semi-natural product,and has good biocompatibility and biodegradability.These unique characteristics make CD widely applied in many fields,especially in the separation and enrichment field.Although the CD-based host-guest chemistry has been extensively developed in the past fifty years,the water solubility of CD makes it difficult to separate from aqueous solutions,limiting the application for separation and enrichment field.CD supermolecular materials effectively overcome this shortcoming and widely were used in the field of separation and enrichment.CD supermolecular materials can not only maintain the structure and properties of the CD itself,but also take the interaction of the carrier with target,playing the synergistic effect of CD and carrier,and at the same time be easy to separate.This paper mainly contains two parts.Tetrafluoroterephthalonitrile cross-linked porous cyclodextrin polymer(P-CDP),is obtained by nucleophilic substitution reaction with many excellent properties,such as high specific surface area,rapid extraction rate,high uptake capacity and strong removal ability toward cationic and neutral pollutants compared with traditional activated carbon.However,P-CDP has a weak ability to remove anionic pollutants and has not been applied to the adsorption and separation of protein macromolecules.In view of this,targeted functional modification of P-CDP was carried out first in this paper,mainly including the following three aspects.(1)Two types of magnetically modified P-CDP were successfully synthesized by means of improving the synthesis method reported in the literature and magnetic functionalization with co-precipitation and multi-step reaction covalent crosslinking.Taking magnetically modified P-CDPs as adsorbents and combining with high performance liquid chromatography,a rapid detection method of four Sudan dyes in foodstuffs and environmental water was established.This method has wide linear ranges(0.1-20 ng/mL),excellent correlation coefficients(R2>0.9981),low limits of detection(0.013-0.054 ng/mL)for Sudan dyes.The recoveries of standard addition test in actual samples(50.0?250.0?500.0 ng/g or 2?10?20 ng/mL)were 85.8%-102.8%,suggesting that the developed methods are promising for accurate quantification of Sudan dyes at trace levels in foodstuffs and environmental water.(2)To improve the affinity of P-CDP for anionic pollutants,ethanolamine and amino-modified P-CDP were prepared,P-CDP-EA and P-CDP-AM.Using methyl orange as an anionic pollutant model,the adsorption behavior of the two functionalized materials was investigated.The polymers exhibited remarkable adsorption efficiency with the maximum adsorption capacity of 625 and 294 mg/g for P-CDP-EA and P-CDP-AM,respectively.The adsorption isotherms better fitted to the Langmuir model and the kinetic study showed being pseudo-second-order adsorption.The as-prepared functionalized P-CDP changed the direction of the dye adsorption from the cation to the anion,which are promising to remove anionic pollutants from wastewater.(3)Based on the fact that the carboxyl group can enhance the nonspecific adsorption of lysozyme,and the cyclodextrin can prevent aggregation of lysozyme in aqueous solution,the carboxyl-functionalized P-CDP(P-CDP-COO-)were synthesized by base-catalyzed hydrolysis of the nitrile group in P-CDP to carboxyl,and applied to the adsorption and separation of lysozyme.Porous structure,large extent of carboxylic functional groups,cyclodextrin's preventing aggregation,and negatively charged make P-CDP-COO-possess an outstanding adsorption capability for lysozyme.The maximum saturated adsorption capacity reaches 1520 mg/g,which is much better than the parent polymer and other reported materials.The as-prepared material was successfully utilized for the selective extraction of lysozyme from the egg white.The porous CD polymers reported so far have been synthesized in the organic phase,and the preparation of these polymers in the aqueous phase remains challenging.In the second part,two novel,low-cost,green porous cyclodextrin polymers are designed and synthesized.The prepared polymers were applied to the adsorption of dyes and the detection of macrolides in complex matrix.(1)Using benzidine or 1,3,5-tris(4-aminophenyl)benzene and ?-CD as monomers,hierarchically porous cyclodextrin polymers(Aryl-CDP-1 and Aryl-CDP-2)were first synthesized with one-pot method based on diazo reaction in aqueous solution under mild conditions.Characterizations show that Aryl-CDP materials are amorphous polymers with moderate surface area and thermal stability,and contain abundant negative charge,suggesting that the green materials have potential application in the field of adsorption and separation.(2)Taking methylene blue as a contaminant model,the adsorption behavior of Aryl-CDP-1 was investigated.The adsorption isotherms better fitted to the Langmuir model and the kinetic study showed being pseudo-second-order adsorption.Aryl-CDP-1 shows excellent adsorption selectivity for cationic dyes.(3)The separation and enrichment properties of Aryl-CDP-2 as a solid-phase extraction sorbent of macrolides were investigated.Aryl-CDP-2 exhibited remarkable adsorption efficiency for three representative macrolides(erythromycin,azithromycin and roxithromycin).The maximum saturated adsorption capacity reaches 555.6,344.8,and 322.6 mg/g,respectively,which is much better than the other reported materials.Combined with ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MSD),the analysis method of macrolides in water,milk and honey samples was established.This method has a linear range of 0.5-500.0 ng/L and the limits of detection in the range of 0.15-1.80 ng/L,suggesting that the developed method is promising for accurate quantification of macrolides at trace levels in foodstuffs and environmental water.