Surface chemical heterogeneity of oxidized carbon particles

The effects of pH, or surface chemistry and of porosity on the heterogeneity of immersed Saran carbons was investigated by film flotation. Even in the presence of methanol, higher pH values were found to enhance the surface hydrophilicity of carbons owing to the dissociation of oxygen functional groups. For carbons with similar oxygen contents, higher CO/CO₂ evolution ratios (i.e., lower acidities) led to diminished pH effects, and to a more hydrophilic response at low pH values. Porosity only appears to affect the rate at which equilibrium flotation is attained.