Fundamentals of Supercritical Extraction From a Solid Matrix

固体基质超临界萃取的基础知识

• 批准号: 9022026
• 负责人: Aydin Akgerman
• 金额: $ 9万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-06-15 至 1994-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9022026&HistoricalAwards=false
• 关键词: Fundamentals; Supercritical; Extraction; Solid; Matrix

The objective of this project is to determine solid/solute (absorbent/adsorbate) interactions in supercritical extraction from solid matrix through determination of adsorption equilibria between dilute supercritical mixtures and well characterized solid matrices, using a dynamic tracer response technique. The partial molar volumes of the adsorbate in the adsorbent are determined through the isothermal density dependence of the solubilities of these solutes in the supercritical phase (date from the literature) combined with the isothermal density dependence of the adsorption equilibrium constants which are measured. Similarly, the heats of adsorption are determined from the isobaric temperature dependence of the adsorption equilibrium constants. Employing the data, a thermodynamic model for adsorbate/adsorbent interactions in presence of a supercritical fluid will be developed. In addition to the adsorption equilibria, the transport and hydrodynamic parameters for supercritical extraction from solid matrices are studied. Together with the adsorption equilibrium constant, analysis of the tracer response data also yields the axial dispersion coefficient, the mass transfer coefficient, and the effective diffusivity of the solute in the pores of the solid matrix at the extraction conditions. A model is proposed for restrictive diffusion in porous particles (effective diffusivity) in presence of supercrtical fluids in terms of the particle morphology, molecular diffusivity, and the ratio of the diffusing molecule diameter to the pore diameter: The results have implications for removal of pollutants from solid adsorbents, for complex mixtures separations and analysis, and for extraction of heat- sensitive chemicals in the food and fragrance industries.

本项目的目标是确定固体/溶质 超临界萃取中的（吸附剂/吸附质）相互作用 通过测定吸附作用从固体基质中分离 稀释的超临界混合物和井之间的平衡 表征固体基质，使用动态示踪剂响应 法 吸附质在溶液中的偏摩尔体积 吸附剂的等温密度 这些溶质的溶解度的依赖性 超临界相（来自文献的数据）与 吸附等温密度依赖性 测量的平衡常数。 类似地， 吸附热由等压 吸附平衡的温度依赖性 constants. 利用这些数据， 吸附物/吸附剂相互作用的存在下， 超临界流体将得到发展。 除吸附平衡外， 超临界萃取流体力学参数 研究了固体基质。 与吸附一起 平衡常数，示踪剂响应数据分析 也产生轴向分散系数，质量 传递系数和有效扩散系数的 提取时固体基质孔隙中的溶质 条件 本文提出了一个限制性扩散模型， 多孔颗粒（有效扩散率）， 超临界流体的颗粒形态， 分子扩散率，以及扩散分子的比率 直径与孔径的关系：结果具有影响 用于从固体吸附剂中去除污染物，用于络合物 混合物分离和分析，以及用于提取热量- 食品和香料工业中的敏感化学品。