Numerical simulation of the sorption phenomena during the transport of VOCs inside a capillary GC column

A mathematical model based on Langmuir kinetic approach is proposed to describe the transport of BTEX molecules (benzene, toluene, ethylbenzene, m-, p- and o-xylene) inside a capillary chromatography column during their separation step. This model is numerically implemented and afterwards it is validated in correlation with experimental data. Since some thermodynamic parameters and chemical coefficients are unknown for our surface kinetics the initial adsorption and desorption coefficients, K_ads and K_des, are derived from the experimental data. Afterwards predictions are achieved with a good level of correlation when calculating the retention time and peak width at the column outlet for an experimental sequence of several different column temperatures and inlet pressures; and comparing these values with the equivalent simulations.