Surface chemistry of silicon nitride powders: adsorption from non-aqueous solutions

• The adsorption behaviour in cyclohexane of different silicon nitride powders have been studied. Adsorption isotherms of organic probe molecules covering a wide spectra of Lewis acidity/basicity showed large variation in adsorption behaviour between the different probes. Mathematical analysis showed that the adsorption data could be described by a Langmuir-Freundlich type of isotherm. Using a previously presented model of the silicon nitride surface, it was possible to relate the variation of isoelectric point in water between the three powders to a difference in the relative site density of silanol and amino groups on the surface. It was found that the maximum concentration (M) of benzoic acid increased linearly while M of pyridine decreased with an increase in the relative amount of amino groups on the surface.

Nyckelord

Adsorption

cyclohexane

silicon nitride powders

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