Design,Synthesis,and Application Of Ionic β-Cyclodextrin Adsorption Materials

As a new type of adsorbent,the ionic β-cyclodextrin adsorbent is characterized by not only retaining the hydrophobic cavity of cyclodextrin,which can package targets with matching size,volume,size,and polarity,but also the charge center on the surface can form an electrostatic interaction with some oppositely charged substances,so the ionic β-cyclodextrin adsorption material exhibits some unique properties and functions that are different from natural and neutral cyclodextrin adsorption materials.By adjusting the type and position of the substituents,and selectively introducing single or multiple charge centers at the 6-position of β-cyclodextrin,β-cyclodextrin derivatives with different ion types and charge the numbers can be obtained.This thesis has carried out a series of research work mainly around the design,synthesis,and application of ionic β-cyclodextrin adsorption materials.Including the following research content:First,two magnetic graphene oxide composites were designed and synthesized,specifically(mGO@ILs(1)-βCD and mGO@ILs(2)-βCD),with different ionic liquid functional group substitution contents on the β-cyclodextrin(β-CD).Comparison of the adsorption performance of the two materials for anionic dyes(lemon yellow(LY),sunset yellow(SY),and ponceau 4R(P4R))in simulated wastewater.Effect of initial pH value,contact time were studied and discussed in terms of affinity and adsorption efficiency,and it was found that under the condition of pH<7,the main mechanism of the adsorption of anionic dyes is electrostatic attraction.The maximum adsorption capacity based on the Langmuir model showed that mGO@ILs(2)-βCD was better than mGO@ILs(1)-βCD.Additionally,the adsorbent maintains excellent adsorption capacity after more cycles of adsorption-desorption and has remarkable selective separability.Secondly,magnetic molecular imprinted polymer(MMIP)with well-defined core-shell nanostructure for extracting fluoroquinolone drugs have been fabricated by surface molecular imprinting method,which uses heptakis β-cyclodextrin-ionic liquid)(ILs(2)-βCD),ofloxacin(OFL),triallyl cyanate(TAC),and azobisisobutyronitrile as the functional monomer,template molecule,crosslinking agent,and initiator,respectively.By coupling the MMIP adsorbent with high-performance liquid chromatography,an approach was established to enhance the selective adsorption of structurally similar FQ compounds in lake water samples.Under the optimal conditions,the method has a wide linear range(0.5-1000 μg·L-1)and a good linear relationship(R2>0.9990).The recoveries of the four FQs ranged from 80.11 to 106.71%,and the limits of detection were between 0.43 and 1.83 μg·L-1.The results show that this watercompatible molecularly imprinted polymer has broad application prospects for the efficient identification and separation and enrichment of trace fluoroquinolones in complex matrices.Finally,a multifunctional adsorbent(PPCD@VI-SSs)by a two-step method was synthesized with βcyclodextrin,imidazole groups,and sulfonic acid groups on the surface,which was applied for simultaneous adsorption of bisphenol A(BPA),methylene blue(MB)and Cu2+,typical pollutants of EDCs,dyes and heavy metals,respectively.In the mono system,the adsorption data of the adsorbent for BPA,MB,and Cu2+ conformed to the Langmuir isotherm model and the maximum adsorption capacity was 180.9,90.2,and 113.9 mg·L-1,respectively.In the binary system,MB and Cu2+ exhibited a synergistic effect in the MB/Cu2+ binary solution;the coexisting Cu2+ showed a negligible effect on MB adsorption at lower Cu2+ concentrations(≤200 mg·L-1),while the removal of Cu2+ was promoted by the coexisting MB in the Cu2+/MB binary system.An adsorption mechanism was proposed:each component of PPCD@VI-SSs played an essential role,the cyclodextrin cavities contributed to entrapment of non-polar BPA,and the surface sulfonic acid group and imidazole ring provide sufficient and diverse binding sites for polar MB and Cu2+.In addition,the composite material’s excellent recyclability and anti-interference ability have great practical application potential in the field of water purification.