Activated carbon surface heterogeneity seen by parallel probing by inverse liquid chromatography at the solid/liquid interface and by gas adsorption analysis at the solid/gas interface

The energetic surface heterogeneity of four different activated carbons was assessed by the parallel probing at the solid/liquid and solid/gas interfaces. At the solid/liquid interface a method of inverse liquid chromatography, frontal analysis by characteristic point was applied using phenylalanine in water solution as a probe molecule. At the solid/gas interface, argon was used as a probe in the low pressure quasi equilibrium volumetry method. The treatment of the adsorption isotherms by the derivative isotherm summation procedure revealed similar adsorption energy distributions for both argon and phenylalanine. Such an agreement between both methods suggests that, at the solid/liquid interface and on the solid/gas interface, the adsorption was mainly controlled by geometric parameters and no specific interaction was observed and physisorbed water did not played a significant role in adsorption process on three from four studied carbons.