Adsorption equilibrium of citric acid from supercritical carbon dioxide/ethanol on cyano column

• Published in: Chinese journal of chemical engineering Vol. 23; no. 6; pp. 905 - 911
• Main Authors: Lü, Huisheng, Wang, Guoqing, Zhang, Minhua, Geng, Zhongfeng, Yang, Miao, Sun, Yanpeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2015
• Subjects: Adsorption isotherm; Citric acid; Cyano column; Isotherm model; 乙醇; 基柱; 平衡吸附; 柠檬酸; 等温线模型; 超临界CO2; 超临界二氧化碳; 饱和吸附量; Cyano column; Isotherm model; Citric acid; Adsorption isotherm
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/j.cjche.2013.10.002

Supercritical adsorption equilibrium has a significant role in defining supercritical adsorption behavior. In this paper, the adsorption equilibrium of citric acid from supercritical CO2/ethanol on a cyano column was systematically investigated with the elution by characteristic point method. Equilibrium loading was obtained at 313.15 K and 321.15 K with supercritical CO2/ethanol densities varying from 0.7068 g·cm-3to 0.8019 g·cm-3. The experimental results showed that the adsorption capacity of citric acid decreased with increasing temperature and increasing density of the supercritical CO2/ethanol mobile phase. The adsorption equilibrium data were fitted well by the Quadratic Hill isotherm model and the isotherms showed anti-Langmuir behavior. The monolayer saturation adsorption capacity of citric acid is in the range of 44.54 mg·cm-3to 64.66 mg·cm-3with an average value of 56.86 mg·cm-3.