Gelation of Aluminum Hydroxide Sols

摘要

The gelation of Al(OH)3 sols obtained from aluminum sec-butoxide is studied as a function of preparation conditions, including pH, temperature, and time of aging. A mechanism of gelation by the action of the anions of acids (NO3-) is proposed. Depending on temperature, it can lead to the building of extended Boehmite ribbons, an action favored by time, increasing anion content, decreasing water content. Below a given temperature it leads to the creation of polymeric structures trapping water to give a clear polymeric complex amorphous gel.