连续式密实移动床逆流操作下轴向解吸K+特性

以吸附K+的001′7强酸型阳离子树脂为固体介质，NaCl溶液为解吸剂，在一套密实移动床装置上，采用连续式液固逆流接触解吸方式，在不同操作条件下考察离子交换柱对K+的轴向解吸特性，并与固定床解吸操作模式进行对比. 结果表明，在移动床操作模式下，离子交换柱内单位树脂累积解吸率沿轴向由上至下逐渐升高，在离子交换柱下部1/5区域内增加较快，部分条件下全柱树脂累积解吸率可达90%以上；解吸剂初始浓度在一定范围内增加时，轴向各区域单位树脂累积解吸率增大，但当解吸剂初始浓度增大到一定值后，离子交换柱轴向不同区域会出现解吸与反吸附交替主导的现象；随离子交换柱内解吸液表观流速增大、树脂移动速度和原始吸附量降低，其轴向各区域的单位树脂累积解吸率增加. 在解吸液单程流过离子交换柱的时间内，采用连续式密实移动床的全柱累积解吸率和K+解吸总量比固定床吸附模式高.

Axial Desorption Characteristics of K+ in Continuous Packed Moving Bed Column under Countercurrent Operation

With 001′7 strong acid cationic resin with adsorbed K+ as solid medium and NaCl solution as desorbent, axial desorption characteristics of ion-exchange column to K+ in a packed moving bed under continuous liquid-solid countercurrent operation were studied in different operating conditions, and compared with a fixed bed. The results showed that in the moving bed, the cumulative desorption rate of unit resin increased gradually from top to bottom along the axial direction, which, especially, increased more rapidly in the lower 1/5 part of ion-exchange column, the full column resin cumulative desorption rate could reach over 90% under some conditions. The cumulative desorption rate of unit resin in each axial region increased when the initial concentration of desorbent increased in a certain range, but when the initial concentration of desorbent increased to a certain value, a phenomenon appeared in different axial regions of the ion exchange column that desorption and antiadsorption alternated in domination. With the increase of apparent velocity of the eluate in the ion exchange column and decrease of resin moving speed and original adsorption capacity, the cumulative desorption rate of unit resin in each axial region increased. The full column resin cumulative desorption rate and desorbed amount of K+ were higher in a continuous moving bed than in a fixed bed during the time of the eluate flowing through the ion exchange column in one-way.