Abstract
n-Hexane and carbon tetrachloride vapour sorption isotherms at 20°C are reported for two series (A and U) of Latvian clays. Samples of the A series were prepared from triassic montmorillonite clays by sulphuric or hydrochloric acid treatment at 100°C. Samples of the U series were prepared from quaternary hydromica clays in the same way. It was found that the vapour sorption isotherms exhibit a reproducible closed hysteresis loop at P/P0 = 0.3–0.99. For samples of series A, both the shape and the location of the hysteresis loop change as the acid concentrations increase. The BET specific surface area of both series samples increases at first and then decreases as the concentration of acid increases. Kelvin pore radii distribution curves have been calculated. It was found that the pore radius increases when the concentration of acid increases. The total pore volume of the samples was estimated as the amount of adsorbed vapour at P/P0=0.99. The pore volume at first increases and then decreases when the concentration of acid increases.
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