Structural and energetic heterogeneities of hybrid carbon-mineral adsorbents

A variety of pyrocarbon-mineral adsorbents (carbosils) were synthesised on the basis of mesoporous silica gel (Si-60, Si-40) and studied by means of the nitrogen adsorption and 1H NMR methods. Structural and energetic parameters were determined using overall adsorption isotherm approximation with consideration for structural heterogeneity described in the terms of different components in the integral equation. Changes in structural parameters as functions of deposit concentration were compared with changes in the free surface energy estimated by using the 1H NMR method with freezing-out of bulk water in aqueous suspension of carbosils. To test proposed integral adsorption isotherm equation, the pore size distributions (PSDs) were determined for mechanical mixtures of four adsorbents (silica gel, fumed silica, activated carbon and carbon black) characterised by different types of the porosity.