This work is part of the effort at the Facility for Adsorbent Characterization and Testing (FACT lab) at the National Institute of Standards and Technology (NIST) to develop reference materials, reference data, and measurement best practices for adsorption metrology. High-pressure surface excess isotherms for CO₂ adsorption on NIST Reference Material 8852 (ammonium ZSM-5) at 15 °C, 25 °C, and 35 °C are reported, expanding on a FACT Lab-organized international interlaboratory study on this sorbent/sorbate pair at 20 °C. The range of temperatures of the present study is of interest for many CO₂ adsorption measurements and applications. Measurements were made using five different adsorption instruments, both manometric and gravimetric. Excellent agreement in the measured isotherms among the instruments was found. An empirical reference equation of the form,

\({n}_{ex,ref}({P}_{eq})=\frac{c}{\{{1+\mathrm{exp}[\left(-\mathrm{ln}\left(P\right)+a\right)/b ]\}}^{b }} ,\)

[n_ex,ref is surface excess uptake (mmol/g); P_eq is equilibrium pressure (MPa); P is (P_eq)/(1 MPa)]; a, b, c are constants] and the 95% uncertainty interval were determined for the isotherms at each of the temperatures. Lastly, the isosteric heat of adsorption is estimated from absolute isotherms derived from the surface excess reference data.

这项工作是美国国家标准与技术研究院 (NIST) 吸附剂表征和测试设施 (FACT 实验室) 的一部分，旨在开发吸附计量学的参考材料、参考数据和测量最佳实践。_{报告了 NIST 参考材料 8852（铵 ZSM-5）在 15°C、25°C 和 35°C 下 CO 2}吸附的高压表面过量等温线，扩展了 FACT Lab 组织的对该吸附剂的国际实验室间研究/山梨酸盐对在 20 °C。本研究的温度范围对于许多 CO ₂吸附测量和应用。使用五种不同的吸附仪器进行测量，包括测压法和重量法。发现仪器之间测量的等温线非常一致。形式的经验参考方程，

\({n}_{ex,ref}({P}_{eq})=\frac{c}{\{{1+\mathrm{exp}[\left(-\mathrm{ln}\left( P\right)+a\right)/b ]\}}^{b }} ,\)

[ n _ex,ref是表面过量吸收 (mmol/g)；P _eq为平衡压力（MPa）；P是( Peq )/(1 _MPa )]；a、b、c是常数]，并确定了每个温度下的等温线的 95% 不确定区间。最后，等量吸附热是根据来自表面过量参考数据的绝对等温线估计的。