A commercial gravimetric sorption analyzer, which is based on a magnetic-suspension balance, was significantly improved to reduce the uncertainty in adsorption measurements. In a previous paper, we investigated the force-transmission error (FTE) of the instrument’s magnetic-suspension coupling, and we analysed the uncertainty of the density measurement. In the present paper, equations for the determination of the adsorption on porous and quasi non-porous materials are provided, where the FTE is taken into account, and a detailed uncertainty analysis is presented. The uncertainty analysis was applied to both the improved measurement system and a typical commercial gravimetric sorption analyzer. Adsorption test measurements were conducted with carbon dioxide along the T = 283 K isotherm at pressures up to the dew-point pressure using both a porous material (zeolite 13X) and a quasi non-porous material (solid metallic sinkers). The major uncertainty contributions for adsorption on the porous material were the mass and volume of the adsorbent sample and the assumption of the density of the adsorbed fluid; for the quasi non-porous material, the main contributions were the weighing values of the balance, the density of the investigated fluid in the gas phase, and the volume of the non-porous material. The influence of the FTE on the adsorption on the porous material was approximately 0.002 mmol⋅g⁻¹, which was negligibly small; but the influence of the FTE was significant in the case of the quasi non-porous material, i.e., approximately 0.7 mmol⋅m⁻² or about 22% of the adsorption capacity with the highest adsorption observed in this work (near the dew-point pressure). This indicates that the influence of the FTE increases significantly with decreasing adsorption capacity of the adsorbent sample.

中文翻译：

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使用商用重量吸收分析仪进行吸附测量的不确定度分析，同时基于磁悬浮天平进行密度测量

基于磁悬浮平衡的商用重量吸收分析仪得到了显着改进，以减少吸附测量的不确定性。在以前的文章中，我们研究了仪器的磁悬浮耦合的力传递误差（FTE），并分析了密度测量的不确定性。在本文中，提供了确定多孔和准非多孔材料吸附的方程，其中考虑了FTE，并进行了详细的不确定性分析。不确定度分析同时应用于改进的测量系统和典型的商用重量吸收分析仪。沿T沿二氧化碳方向进行吸附测试 使用多孔材料（13X型沸石）和准无孔材料（固态金属沉降片），在高达露点压力的压力下= 283 K等温线。吸附在多孔材料上的主要不确定性因素是吸附剂样品的质量和体积以及所吸附流体密度的假设。对于准无孔材料，主要贡献是天平的称重值，气相中被研究流体的密度以及无孔材料的体积。FTE对在多孔材料上的吸附的影响约为0.002mmol·g ^-1，可以忽略不计。但是在准无孔材料的情况下，FTE的影响很大，即约为0.7 mmol·m ^-2在这项工作中观察到的最高吸附量（接近露点压力）约为吸附量的22％。这表明FTE的影响随着吸附剂样品的吸附能力的降低而显着增加。