STRATUL DUBLU ELECTRIC AL MONTMORILONITULUI. III. CARACTERISTICILE STRATULUI COMPACT STERN

Vasile RUSU Institutul de Chimie al AŞM

Abstract

MONTMORILLONITE EDL. III. CHARACTERISTICS OF STERN COMPACT LAYER 

It was performed analysis of the characteristics of the electric double layer (EDL) close to the basal surface and edge surface of H-montmorillonite and pillared Al-montmorillonite. The thickness of compact layer (Stern layer) was esti-mated on the basis of ions dimensions proposed by Marcus. For H-montmorillonite, the dielectric constant for Stern layer is about rI ≈ 7,2 for EDL in the proximity of the basal surface and about rI ≈ 8,5 for EDL in the proximity of the edge surface, while the surface potential 0 for these surfaces is about -0,083 ÷ -0,084 V. For pillared Al-montmorillonite, the corresponding dielectric constants for these surfaces are rI ≈ 9 and rI ≈ 12, and the the surface potential -0,121 ÷ -0,117 V in accordance with values established from Gouy-Chapman model. The electrical capacity of compact layer was estimated on the basis of established characteristics (δ, rI) and was established the increasing of electrical capacity as the thickness of compact layer is decreasing. 

Keywords: H-montmorillonite, pillared Al-montmorillonite, electrical double layer.