串级萃取理论在离子交换固定床吸附过程中的应用

Application of countercurrent extraction theory in ion exchange fixed bed adsorption process

通过对比固定床吸附过程与串级萃取过程,发现固定床上的吸附过程相当于无穷多级溶剂萃取过程的串联。基于串级萃取的模型结构与树脂的等温吸附方程,得到不同吸附类型下穿透曲线的描述公式。以D850树脂吸附Cu(Ⅱ)离子的过程为例,对建立的模型进行验证,并且分析了各种初始参数的变化对模型精确度的影响。结果表明:该模型可以很好地描述固定床吸附过程,在不同流量与不同初始浓度条件下预测方程与穿透曲线之间的相关系数均可达到0.99以上。

By comparing the fixed-bed adsorption process and countercurrent extraction process,it is found that the adsorption process on a fixed-bed is equivalent to an infinite series of solvent extraction processes in series.Based on the model structure of the countercurrent extraction and the isothermal adsorption equation of the resin,the description formula of the penetration curve under different adsorption types was obtained.Taking the adsorption of Cu(Ⅱ)ion on D850 resin as an example,the established model was validated and the influence of various initial parameters on the accuracy of the model is analyzed.The results show that the correlation coefficient can reach more than 0.99 under different flow rates and different initial concentrations,and the correlation coefficient can reach 0.99 when the height-diameter ratio is greater than 1.59.