Investigation of the Adsorption Properties of a Nanodiamond Surface after Liquid-Phase Oxidation

In this work, the hydrophilicity of a nanodiamond (ND) with an additionally oxidized surface was studied by reversed gas chromatography. Specific retention volumes V and differential-molar isosteric heats of adsorption of water and heptane q st were measured. It is established that values V of water and heptane on ND with an oxidized surface increased by a factor of 2–4 compared to the initial detonation ND. Additional oxidation increases the density (per unit surface) of functional groups, providing adsorption interaction of the surface with both water and heptane. Heat for water q st practically did not change, and heat for heptane q st decreases as the surface is filled from −60.1 to −33.0 kJ/mol, which indicates a change in the nature of the adsorption sites responsible for the retention of heptane.