β-环糊精/聚乙烯醇/丙烯酸水凝胶对左氧氟沙星吸附性能及机理研究

Study on the adsorption property and mechanism ofβ-cyclodextrin/polyvinyl alcohol/acrylic acid hydrogel for levofloxacin

以β-环糊精(β-CD)、聚乙烯醇(PVA)、丙烯酸(AA)为单体,过硫酸铵(APS)为引发剂,采用水溶液聚合法合成β-环糊精/聚乙烯醇/丙烯酸(β-CD/PVA/PAA)水凝胶。采用SEM、FT-IR和XRD对所制备的水凝胶进行分析,考察了外界环境因素对β-CD/PVA/PAA水凝胶吸附性能的影响,探讨了β-CD/PVA/PAA水凝胶对左氧氟沙星(LEV)的吸附动力学和吸附热力学行为。结果表明,所制备的β-CD/PVA/PAA水凝胶具有清晰的三维网络多孔结构;降低LEV溶液的pH值和吸附反应温度有利于β-CD/PVA/PAA水凝胶对LEV吸附反应的进行;干扰离子(Na^(+)、Mg^(2+)、Al^(3+))的存在会在不同程度上影响β-CD/PVA/PAA水凝胶对LEV的吸附。β-CD/PVA/PAA水凝胶对LEV的吸附动力学过程符合准二级反应动力学模型(R 2>0.9885、25℃时),边界层扩散和颗粒内扩散过程是整个吸附过程的主要控速步骤,吸附过程主要为化学吸附;与Langmuir和Temkin吸附等温模型相比,β-CD/PVA/PAA水凝胶对LEV的吸附等温线更符合Freundlich吸附等温模型(R 2>0.9831、25℃时),吸附过程更倾向于不均匀的多分子层吸附;整体吸附过程为自发进行的无序性降低的放热反应。在最优条件下,β-CD/PVA/PAA水凝胶经过4次脱附再生后仍可保持近60%的吸附性能。

β-cyclodextrin(β-CD),polyvinyl alcohol(PVA),and acrylic acid(AA)were used as monomers,and ammonium persulfate was used as an initiator,theβ-cyclodextrin/polyvinyl alcohol/acrylic acid(β-CD/PVA/PAA)hydrogel was prepared by aqueous polymerization.The samples were characterized by SEM,FT-IR and XRD.β-CD/PVA/PAA hydrogel was analyzed,which influenced external environmental factors on theβ-CD/PVA/PAA hydrogel adsorption performance,and the kinetic behavior ofβ-CD/PVA/PAA hydrogel on levofloxacin(LEV)adsorption was explored.The results concluded that the preparedβ-CD/PVA/PAA hydrogel has a well-defined three-dimensional network structure.The decrease in the pH of the LEV solution and the reduction in the adsorption temperature facilitated the adsorption reaction ofβ-CD/PVA/PAA hydrogel on LEV.The existence of interfering ions(Na^(+)、Mg^(2+)、Al^(3+))affected the stability of the system to varying degrees adsorption of LEV onβ-CD/PVA/PAA hydrogel.The adsorption kinetics ofβ-CD/PVA/PAA hydrogel on LEV conforms to the pseudo second order kinetic model(R 2>0.9885,25℃).The diffusion process of the boundary layer and the diffusion process inside the particle were the main speed controlling steps of the whole adsorption process,and the adsorption process was mainly chemical adsorption.Compared with Langmuir and Temkin adsorption isothermal models,the adsorption isotherms ofβ-CD/PVA/PAA hydrogel on LEV were more consistent with Freundlich adsorption isothermal model(R 2>0.9831,25℃),and the adsorption process tended to be heterogeneous adsorption.The adsorption process inclined more toward the adsorption of uniform multi-molecular layers.The whole adsorption reaction was spontaneous and exothermic reaction with decreasing chaos.Theβ-CD/PVA/PAA hydrogel retained 60%adsorption properties after 4 adsorption-desorption under optimal conditions.