Selective gas adsorption by amorphous clay-mineral derivatives

Amorphous derivates prepared by aqueous reaction of various aluminosilicate clay minerals with concentrated KF solution at 80-110 degrees C were studi ed for their gas adsorption properties. The four clay minerals studied are halloysite, a well-crystallized kaolinite, a poorly crystallized kaolinite, and a montmorillonite. The gases tested are N-2, O-2, CH4, CO, CO2, and C2 H2. The kaolin-group mineral derivatives are characterized by substantial r eduction in particle size, high specific surface, and significant selectivi ty towards CO2 and C2H2 relative to the other gases. The montmorillonite de rivative shows no increase in adsorption over the starting material, howeve r, for all the materials high adsorption of CO2 and C2H2 was observed. Leve ls of gas adsorption and gas adsorption ratios are comparable to pillared c lays.