© 2018, The Author(s). This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM 8852 (ammonium ZSM-5 zeolite), at 293.15 K (20 °C) from 1 kPa up to 4.5 MPa. Eleven laboratories participated in this exercise and, for the first time, high-pressure adsorption reference data are reported using a reference material. An empirical reference equation nex=d(1+exp[(-ln(P)+a)/b])c, [nex-surface excess uptake (mmol/g), P-equilibrium pressure (MPa), a = −6.22, b = 1.97, c = 4.73, and d = 3.87] along with the 95% uncertainty interval (Uk = 2 = 0.075 mmol/g) were determined for the reference isotherm using a Bayesian, Markov Chain Monte Carlo method. Together, this zeolitic reference material and the associated adsorption data provide a means for laboratories to test and validate high-pressure adsorption equipment and measurements. Recommendations are provided for measuring reliable high-pressure adsorption isotherms using this material, including activation procedures, data processing methods to determine surface excess uptake, and the appropriate equation of state to be used.
Nguyen, H. G.T.; Espinal, L.; van Zee, R. D.; Thommes, M.; Toman, B.; Hudson, M. S.L.; Mangano, E.; Brandani, S.; Broom, D. P.; Benham, M. J.; Cychosz, K.; Bertier, P.; Yang, F.; Krooss, B. M.; Siegelman, R. L.; Hakuman, M.; Nakai, K.; Ebner, A. D.; Erden, L.; Ritter, J. A.; Moran, A.; Talu, Orhan; Huang, Y.; Walton, K. S.; Billemont, P.; and De Weireld, G., "A Reference High-Pressure CO2 Adsorption Isotherm for Ammonium ZSM-5 Zeolite: Results of an Interlaboratory Study" (2018). Chemical & Biomedical Engineering Faculty Publications. 186.
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