Determination of surface free energy components for heterogeneous solids by means of inverse gas chromatography at finite concentrations

The approach for calculating the adsorption free energy and adsorption energy distributions for a heterogeneous solid surface as the sum of two uniform functions directly from co-ordinates of the tail of the probe's chromatographic peak is presented and discussed. Distribution functions are derived from data collected for the series of test adsorbates (n-alkanes C-5-C-10 and five polar organic compounds) by means of inverse gas chromatography at finite concentrations. Average dispersive components of surface free energy and the donor/acceptor components of the adsorption energy in the monolayer region for the parent and mixed Si and Al pyrogenic oxides are also determined and discussed.