Influencing factors on kaolinite–potassium acetate intercalation complexes

This paper presents an immersion method for preparing the kaolinite–potassium acetate intercalation complexes. The effectiveness of intercalation and influencing factors were analysed and evaluated. The results show that the intercalation of kaolinite by potassium acetate is strongly related to crystallinity of kaolinite, concentration of intercalating agent solution, aging time and pH. The well-crystallized kaolinite is conducive to intercalation by potassium acetate. A higher concentration of intercalating agent (≥ 30%) can complete the intercalation in a short time (< 12 h), but at lower concentrations intercalation took significantly longer (≥ 144 h). The weak alkaline condition of pH = 10 proved to be the most suitable environment for the formation of intercalation complex. A good intercalated complex can be obtained at room temperature.

Research Highlights
► The immersion method was used to intercalate potassium acetate into the interlayer of kaolinite.
► The intercalation ratio depends on various factors. Some factors are related to the kaolinite properties especially the degree of ordering, besides, there are other factors including the type of the regent, temperature, reaction time and pH.
► The intercalation solution concentration at 30% results a better intercalation than the other solution concentrations and 12 h is better for the solution concentration at 30%.
► The two adjacent layers in kaolinite deprotonated to form the complex AlO- and SiO- with negative charge under alkaline conditions. This is beneficial to intercalation.