Predição do equilíbrio da adsorção multicomponente de gases utilizando o modelo aNRTL para cálculo dos coeficientes de atividade na fase adsorvida

Abstract

Three non-ideal models were developed to predict the adsorption behavior of binary mixtures based on the adjustment of parameters from single-component systems: the VSM-aNRTL and two Langmuir Thermodynamic Multi-Region Expanded models, one based on the maximum adsorption capacity (LTEMR) and another on the adsorbed molar area (LTEMR-area). All of them utilize the new Adsorption Non-Random Two-Liquid (aNRTL) model to calculate the activity coefficient in the adsorbed phase. Experimental single-component adsorption equilibrium data from the NIST/ARPA-E Database were adjusted to obtain the necessary parameters. These parameters were then used to predict equilibrium data for 12 binary systems at different temperatures, involving various gases. For comparison, the idealized model of the Ideal Adsorbed Solution Theory (IAST) and the traditional VSM, which employs Wilson's equations (VSM-Wilson) to calculate the activity coefficients in the adsorbed phase, were used. The proposed models proved effective in correlating the adsorption isotherms of pure components, with high correlation coefficients and a reduction in the number of adjustable parameters compared to VSM-Wilson. In predicting equilibrium data of binary mixtures, both VSM-aNRTL and LTEMR-area showed lower deviations compared to the IAST and VSM-Wilson models, notably the VSM-aNRTL, which significantly outperformed the comparison models. The superior performance of the proposed models was also confirmed by the Akaike Information Criterion (AIC). Notably, VSM-aNRTL and LTEMR-area achieved these results by incorporating only one additional parameter relative to IAST and with fewer parameters than VSM-Wilson, evidencing their efficiency and precision in predicting adsorption in binary systems.