Vol 7, No 2 (2016) > Mechanical Engineering >

An Adsorption Equilibria Model for Steady State Analysis

Azhar Bin Ismail, Karan M. Sabnani, Li Ang, Kim Choon Ng



The investigation of
adsorption isotherms is a prime factor in the ongoing development of adsorption
cycles for a spectrum of advanced, thermally-driven engineering applications,
including refrigeration, natural gas storage, and desalination processes. In
this work, a novel semi-empirical mathematical model has been derived that
significantly enhances the prediction of the steady state uptake in adsorbent
surfaces. This model, a combination of classical Langmuir and a novel modern
adsorption isotherm equation, allows for a higher degree of regression of both
energetically homogenous and heterogeneous adsorbent surfaces compared to
several isolated classical and modern isotherm models, and has the ability to
regress isotherms for all six types under the IUPAC classification. Using a unified
thermodynamic framework, a single asymmetrical energy distribution function
(EDF) has also been proposed that directly relates the mathematical model to
the adsorption isotherm types. This fits well with the statistical rate theory
approach and offers mechanistic insights into adsorption isotherms.
Keywords: Adsorption; Energy distribution function; Statistical rate theory; Universal isotherm model

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