Thermodynamic trends for the adsorption of non polar gases on activated carbons employing a new adsorption isotherm modelling
Thermodynamic trends for the adsorption of non polar gases on activated carbons employing a new adsorption isotherm modelling
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DOI：
10.1016/j.applthermaleng.2016.05.160
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发表时间：
2016-07-25
影响因子：
6.4
通讯作者：
Chakraborty, Anutosh
中科院分区：
文献类型：
--
作者：
Chakraborty, Anutosh
本文报道了一个理解活性炭与各种非极性吸附分子的表面能和表面结构相互作用因素的热力学框架。为了更好地理解，作者利用活性炭和一些非极性气体如H-2、Ar、N-2、CO2、O-2和CH4的吸附吸附数据，计算了在压力-温度-吸附坐标系下的吸附焓和熵。根据所提出的模型和实验数据计算了均方根误差。结果表明，该模型与实验数据吻合较好，得到了最小均方根误差。通过理论观察，得到了微孔活性炭的非均质因子(m)为1，介孔活性炭为2，并且发现非极性气体在活性炭上的相互作用对吸附剂孔隙几何形状和吸附物尺寸更为敏感。研究还发现，吸附剂-吸附体系的焓和熵与吸附分子的动力学直径密切相关，而与吸附分子动力学直径等效的孔隙大小是在低压下储存更多吸附质的关键。例如，活性炭的孔径大致保持在3.8埃，以储存更多的甲烷，3.3埃，以捕获更多的二氧化碳。(C) 2016 Elsevier Ltd.版权所有。
In this paper, the author reports a thermodynamic framework for understanding the surface - energy and the surface - structural interaction factors of activated carbons with various non polar adsorbate molecules. For better understanding, the author employs adsorption uptakes data of activated carbons and some non-polar gases such as H-2, Ar, N-2, CO2, O-2 and CH4 to calculate the enthalpy and entropy of adsorption in pressure-temperature-uptake coordinate systems. The RMS errors are calculated with respect to the proposed model and the experimental data. The minimum RMSEs are found as the model fits well with the experimental data. From theoretical observations, the heterogeneity factors (m) are obtained 1 for microporous and 2 for mesoporous activated carbons, and the interactions of non-polar gases on activated carbons are found to be more sensitive to the adsorbent pore geometry and the adsorbate size. It is also established that the enthalpy and entropy of adsorbent - adsorbate system are closely related to the kinetic diameter of adsorbate molecules, and the pore size equivalent to adsorbate kinetic diameter is the key to store more adsorbate at low pressures. For example, the pore width of activated carbon is roughly maintained 3.8 angstrom for more methane storage and 3.3 angstrom for more CO2 captures. (C) 2016 Elsevier Ltd. All rights reserved.