(162f) Evolution of the Concentration Pulse Method (CPM) from Determining Henry’s Constant Data to Mixture Adsorption Behaviour

New developments in material chemistry have led to the synthesis of novel types of highly selective adsorbents including metal organic frameworks and zeolites with morphology such as defined pore structures, very high surface areas and different active sites among many others. Typically, the morphology and chemical analysis of these materials are first determined. This is followed by characterization of the pure component adsorption equilibria isotherms and kinetics at different temperatures and pressures, with corresponding temperature dependent isotherm equations utilized to describe the adsorption equilibria.

Equations predicting the mixture adsorption behavior such as Extended Langmuir, Ideal Adsorbed Solution Theory (IAST) and Vacancy Solution Theory (VSM) are used to infer the mixture adsorption performance of these new materials. However, while many mixture isotherm predictions are accurate, deviations with respect to experimental measurements are observed particularly for highly selective or non-ideal systems. Standard chromatographic methods such as the Concentration Pulse Method (CPM) serve as a useful tool to verify mixture adsorption performance prior to larger scale analysis. The CPM is a fast and affordable method that can be utilized to verify mixture adsorption performance requiring little amount of adsorbent material. In this presentation, the use of the CPM is discussed within a wide range of adsorption applications including its use to generate Henry’s Law constants at low concentrations, thermodynamic data, and adsorption mixture isotherms with a series of novel adsorbents. The CPM provides versatility and its use in combination with other experimental and computational techniques make for effective and practical screening of large number of adsorbents.