CHARACTERIZATION OF MICROPORES OF IMOGOLITE BY MEASURING RETENTION OF QUATERNARY AMMONIUM CHLORIDES AND WATER
1972 Volume 4 Issue 3 Pages 127-136
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1972 Volume 4 Issue 3 Pages 127-136
The micropore status of air-dry and preheated imogolites has been examined by measuring retention of (CH3) 4NCl, (C2H5) 4NCl, (C4H9) 4NCl, (CH3) 2 (C6H5)(C6H5CH2) NCl and water. Interactions between the salt and imogolite were followed by observing the moist or dry appearance of the clay-salt mixture when the salt is deliquescent and by observing the changes of the x-ray pattern of imogolite. The adsorption of water vapor at various relative humidities was determined by gravimetry.
No stoichiometrical relationship was found between the maximum amounts of different salts retained by imogolite. The volume ratios of the salt and water at their retention maxima to the solid phase of imogolite were calculated from the retention data. They were found in ranges 1.3 to 1.6 and 0.5 to 1.1 for the air-dry and preheated imogolites, respectively. The difference between them gave a measure of the void ratio of the inter-structure-unit pores. The collapse of these pores by heating and its inhibition by the salt uptake were indicated by x-ray analysis. The volume ratios obtained with the preheated imogolite increased with the increasing size of the cation up to (C4H9) 4N+, but the largest cation (CH3) 2 (C6H5)(C6H5CH2) N+ gave the lowest value. On this basis, the presence of the intra-structure-unit pores of about 10Å in diameter was inferred.
