L-酪氨酸在732阳离子交换树脂上吸附平衡与动力学研究

研究搅拌槽中732阳离子交换树脂吸附L-酪氨酸的交换平衡和动力学特性,考查了搅拌速度、温度、料液初始pH值、树脂粒径和料液初浓度对离子交换过程的影响.在研究的温度和浓度范围内,该离子交换等温线符合Henry等温式.搅拌速度为350rpm时,可以将外传质阻力忽略.料液初始pH值介于2.5～5.5 时,对交换量影响不大,而料液中Na 的存在会降低树脂的交换量.在忽略外传质阻力的条件下,采用不同粒径计算方法对动力学曲线影响很小.用间歇搅拌槽吸附动力学模型拟合出无外传质阻力条件下、不同初始浓度条件下离子交换的表面扩散系数Ds.结果表明,随着初始浓度的增大,Ds的数量级始终在10-8左右.

STUDY ON ADSORPTION EQUILIBRIUM AND KINETICS OF L-TYROSINE ON 732 CATION-EXCHANGE RESIN IN A BATCH ADSORBER

This paper was concerned with the adsorption equilibrium and kinetics of L-tyrosine on 732 cation-exchange resin in a batch adsorber. The effects of the mixing rate, the initial pH value, the radial of the resin and the concentration of the feed on the iron exchange process were studied. The equilibrium agreed well with Henry Law under the conditions of experiments. For eliminating the effect of film mass transfer resistance, the mixing rate was set not less than 350rpm. There was no significant effect to the process when pH value of the feed was between 2.5 and 5.5, and the existence of Na could reduce the exchanging capability of the resin. Under the condition that the external fluid film mass transfer resistance was eliminated, the different calculating methods of the average radius made little effects to the result. The surface diffusion coefficients of the process with different initial concentrations of the feed were calculated by the batch adsorption model. The result showed that the magnitude order of DS and the initial concentration of the feed were irrespective.