Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA.
Langmuir. 2011 Apr 19;27(8):4700-12. doi: 10.1021/la104965w. Epub 2011 Mar 17.
A new model has been developed for predicting mixed-gas adsorption equilibria from multicomponent gas mixtures based on the dual-process Langmuir (DPL) formulation. It predicts ideal, nonideal, and azeotropic adsorbed solution behavior from a knowledge of only single-component adsorption isotherms and the assertion that each binary pair in the gas mixture correlates in either a perfect positive (PP) or perfect negative (PN) fashion on each of the two Langmuir sites. The strictly PP and strictly PN formulations thus provide a simple means for determining distinct and absolute bounds of the behavior of each binary pair, and the PP or PN behavior can be confirmed by comparing predictions to binary experimental adsorption equilibria or from intuitive knowledge of binary pairwise adsorbate-adsorbent interactions. The extension to ternary and higher-order systems is straightforward on the basis of the pairwise additivity of the binary adsorbent-adsorbate interactions and two rules that logically restrict the combinations of PP and PN behaviors between binary pairs in a multicomponent system. Many ideal and nonideal binary systems and two ternary systems were tested against the DPL model. Each binary adsorbate-adsorbent pair exhibited either PP or PN behavior but nothing in between. This binary information was used successfully to predict ternary adsorption equilibria based on binary pairwise additivity. Overall, predictions from the DPL model were comparable to or significantly better than those from other models in the literature, revealing that its correlative and predictive powers are universally applicable. Because it is loading-explicit, simple to use, and also accurate, the DPL model may be one of the best equilibrium models to use in gas-phase adsorption process simulation.
一种新的模型已经被开发出来，用于基于双过程朗缪尔（DPL）公式从多组分气体混合物中预测混合气体吸附平衡。它仅根据单组分吸附等温线和断言预测理想、非理想和共沸吸附溶液行为，即混合物中的每个二元对在两个朗缪尔位上以完全正（PP）或完全负（PN）的方式相关。因此，严格的 PP 和严格的 PN 公式为确定每个二元对行为的独特和绝对界限提供了一种简单的方法，并且可以通过将预测与二元实验吸附平衡进行比较或从二元成对吸附质-吸附剂相互作用的直观知识来确认 PP 或 PN 行为。基于二元吸附质-吸附剂相互作用的加和性以及在多组分系统中限制二元对 PP 和 PN 行为组合的两个规则，很容易将其扩展到三元和更高阶系统。该模型对许多理想和非理想二元系统和两个三元系统进行了测试。每个二元吸附质-吸附剂对都表现出 PP 或 PN 行为，但没有介于两者之间的行为。这种二元信息成功地用于基于二元成对加和性预测三元吸附平衡。总体而言，DPL 模型的预测与文献中的其他模型相当或更好，表明其相关性和预测能力具有普遍性。由于它是加载显式的、使用简单且准确，DPL 模型可能是用于气相吸附过程模拟的最佳平衡模型之一。
