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 \({n_{ex}}=\frac{d}{{{{(1+\exp [\left( { - {\text{ln}}(P)+a} \right)/b~])}^{c~~}}}}~,\) [n_ex-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 (U_k = 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.

中文翻译：

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铵 ZSM-5 沸石的参考高压 CO2 吸附等温线：实验室间研究的结果。

本文报告了由美国国家标准与技术研究院 (NIST) 领导的一项国际实验室间研究的结果，该研究涉及 NIST 参考材料 RM 8852（铵 ZSM-5 沸石）上高压表面过量二氧化碳吸附等温线的测量， 293.15 K (20 °C)，从 1 kPa 到 4.5 MPa。十一个实验室参与了这项活动，并且首次使用参考材料报告了高压吸附参考数据。经验参考方程\({n_{ex}}=\frac{d}{{{{(1+\exp [\left( { - {\text{ln}}(P)+a} \right)/ b~])}^{c~~}}}}~,\) [ n _ex - 表面过量吸收量 (mmol/g), P - 平衡压力 (MPa), a  = -6.22, b  = 1.97, c  = 4.73，d  = 3.87] 以及 95% 不确定性区间 ( U _{k  = 2}  = 0.075 mmol/g) 使用贝叶斯马尔可夫链蒙特卡罗方法确定参考等温线。这种沸石参考材料和相关的吸附数据共同为实验室提供了一种测试和验证高压吸附设备和测量的方法。提供了使用该材料测量可靠的高压吸附等温线的建议，包括活化程序、确定表面过量吸收的数据处理方法以及要使用的适当的状态方程。