Jiao Pengfei, Zhang Xin, Wei Yuping, Meng Yiyan
Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agricultural Engineering, Nanyang Normal University, Nanyang 473061, Henan, China.
ACS Omega. 2022 Mar 9;7(11):9614-9621. doi: 10.1021/acsomega.1c06960. eCollection 2022 Mar 22.
The adsorption amount and selectivity of L-tryptophan (l-Trp) on the hydrophobic interaction and ion exchange mixed-mode chromatography medium HD-1 were studied as well as the salt resistance of the resin via adsorption equilibrium experiments. The adsorption mechanisms of l-Trp were illuminated by combining adsorption equilibria and a kinetics analysis. The separation effect was studied by dynamic separation experiments in a fixed-bed. The results indicate that an increase of the concentration proportion of l-Trp zwitterion benefits the adsorption of l-Trp. The resin shows a high adsorption selectivity for l-Trp at different pH values. The adsorption amount of l-Trp is not affected significantly by NaCl. Various groups play a role in the adsorption of l-Trp. An adsorption energy lower than 8 kJ/mol indicates that the adsorption of l-Trp is mainly based on non-electrostatic interactions, with an electrostatic interaction as a supplement. The adsorption equilibrium model considering the dissociation equilibrium of the resin and l-Trp proposed in this work can simulate the adsorption equilibrium data of l-Trp at different pH values as well. The mass transfer rate of l-Trp is controlled by intraparticle and liquid film diffusion simultaneously. The fixed-bed packed with resin HD-1 can separate l-Trp with the purity of l-Trp higher than 99%, recovery rate higher than 95%, and concentration of 4.69 × 10 mol/L.
通过吸附平衡实验研究了L-色氨酸（l-Trp）在疏水作用和离子交换混合模式色谱介质HD-1上的吸附量、选择性以及该树脂的耐盐性。结合吸附平衡和动力学分析阐明了l-Trp的吸附机制。通过固定床动态分离实验研究了分离效果。结果表明，l-Trp两性离子浓度比例的增加有利于l-Trp的吸附。该树脂在不同pH值下对l-Trp表现出高吸附选择性。l-Trp的吸附量受NaCl影响不显著。多种基团在l-Trp的吸附中起作用。低于8 kJ/mol的吸附能表明l-Trp的吸附主要基于非静电相互作用，以静电相互作用为辅。本文提出的考虑树脂和l-Trp解离平衡的吸附平衡模型也能模拟不同pH值下l-Trp的吸附平衡数据。l-Trp的传质速率同时受颗粒内扩散和液膜扩散控制。装填树脂HD-1的固定床可分离l-Trp，l-Trp纯度高于99%，回收率高于95%，浓度为4.69×10 mol/L。
