Title : Quantitative analysis on collective interlaboratory adsorption data on ZIF-8
Abstract:
Gas adsorption, a surface phenomenon leading to densification of gas molecules on a solid surface, is important in many energy and environmental applications, such as efficient separation processes, carbon capture, and geological carbon storage. Experimental measurements of adsorbed amounts of gases, generally expressed as adsorption isotherms, on various adsorbents are crucial in estimating the adsorption capacity and gas selectivity of the adsorbents and evaluating their performance in the applications stated above. However, there has been a lack of reproducibility in the experimentally measured adsorption isotherms reported in the literature, which potentially leads to incorrect estimation of the adsorption properties of adsorbent materials. In this study, experimental adsorption isotherms of CO2 on ZIF-8, a commonly studied adsorption system for future separation processes, that are available on the Database of Novel and Emerging Adsorbent Materials established by the National Institute of Standards and Technology have been collected and fitted using an empirical adsorption equation. The spread of the isotherms has been then quantified using the box-and-whisker plot analysis and its impact on the determination of the adsorption properties, specifically the limiting heat of adsorption, is reported. The results demonstrate a significant spread of the collected isotherms with clearly identified outliers, showing the importance of increasing the reproducibility of adsorption isotherm measurement.
Audience take-away:
- The importance of repeatability of experimental measurements
- Possible sources of differences in experimental measurements
- The need to report experimental details in reporting data
