抄録
Studies on synthesis of allophane and imogolite are briefly reviewed.
Imogolite is synthesized by heating partially neutralized and slightly re-acidified solutions containing monomeric silicic acid and aluminum salts. The optimum Si/Al molar ratio is slightly greater than 0.5. Allophane is synthesized by heating neutralized solutions which have Si/Al molar ratio of 0.5 to 4. In the light of recent studies on the reactions between monomeric silicic acid and aluminumions, imogoliteis considered to from by the growth of ionic “proto-imogolite” Allophane is considered to form by reorganization of the structure of precipitated noncrystalline aluminum silic ates.
The structure and properties of synthetic allophane and imogolite are considered to be essentially the same as those of natural counterparts except that the diameter of the tubular structural unit of the synthetic imogolite is greater than that of naturalimogolite.
