Characterization of clays by organic compounds

TLDR

Reliable characterization of clay minerals is essential for diverse fields such as soil science and ceramics. Four clay–organic reactions—staining/dye adsorption, glycerol/glycol adsorption, intercalation, and alkylammonium ion exchange—provide a framework for clay mineral characterization. Dye and glycerol adsorption enable preliminary clay group identification, intercalation distinguishes subtle kaolin variations beyond XRD/DTA, and alkylammonium ion exchange offers the most sensitive method for smectite characterization and detecting layer‑charge changes.

Abstract

Abstract Many problems—from soil research to ceramics—require a reliable characterization of the clay minerals involved. This can be done using four clay-organic reactions: (i) staining tests and dye adsorption; (ii) glycerol and glycol adsorption; (iii) intercalation; (iv) alkylammonium ion exchange. Dye adsorption (staining tests) and glycerol adsorption allow a preliminary identification of the clay mineral groups. Intercalation reactions indicate minute differences between kaolins which cannot be detected by XRD and DTA. Alkylammonium ion exchange provides the best method for characterizing smectites and is sensitive to changes in the layer charge.