固定床动力学模型在离子交换过程中的应用

为了掌握所选的Thomas模型,Yoon-Nelson模型和Adams-Bohart模型在固定床米格列醇离子交换过程中的应用情况,实验借助对不同质量浓度的米格列醇溶液在定量树脂和固定流速下研究其在固定床中离子交换过程,并通过对透过曲线实验数据分析来验证相关固定床动力学模型在此过程中的有效性。结果表明:固定床上样液质量浓度增大,达到平衡饱和点的时间将缩短,传质区长度增大,吸附率变小,上样液质量浓度在8 mg/mL时吸附量达到最大;用动力学模型拟合透过曲线的过程参数,结果表明Thomas模型和Yoon-Nelson模型具有较好的相关系数,Thomas模型的速率常数和最大吸附量值随着上样液质量浓度的降低而增大,Yoon-Nelson模型的速率常数随着上样液质量浓度的降低而减小,且在Yoon-Nelson模型中计算得到的透过曲线中出口质量浓度与上样质量浓度比值为1/2时所对应的计算值和实验值相差很小,Thomas模型和Yoon-Nelson模型可用于该过程的离子交换性研究。

Application of kinetic models of fixed bed for ion exchange process

In order to grasp the application of the selected Thomas model,Yoon-Nelson model and the Adams-Bohart model in a fixed bed for ion exchange process of miglitol,the ion exchange adsorption behavior of the different mass concentration of miglitol solution with a given flow rate and fixed resins was investigated.The effective dynamic models in fixed bed were verified according to the analysis of the experimental data for breakthrough curves.The results show that the equilibrium point time is smaller as the inlet mass concentration increases.The mass transfer zone(MTZ) changes big and adsorption rate lessens.The adsorption capacity reaches maximum with the inlet mass concentration of 8 mg/mL.In addition,the dynamic mathematics model was used to fit the experimental data of breakthrough curves,and it reveals that there are good values of the correlation coefficient for Thomas model and Yoon-Nelson model.The rate constant and the maximum adsorption capacity of resins in Thomas model can be added as the inlet mass concentration decreases,and contrary to the rate constant in Yoon-Nelson model.Moreover,τ is the time required for 50% sorbate breakthrough,there is little difference between the calculated parameters and experimental values,which infers that Thomas model and Yoon-Nelson model can be applied to explore the system of ion exchange process.