Date of Award
Masters of Science
Charles B. Hurd
The purpose of this investigation was to determine the effect of pH on the time of set of silicic acid gels and to find out how the pH changes as the sol stands, during the setting process. Several theses and papers on the effect of pH on the setting of silicic acid gels have already been written by C.B. Hurd and students at Union College (2, 30, .33-35, 38, 42, 70 ) . This time we were particularly .interested in . getting accurate results for the alkaline region. The silicic acid gels were made by reaction of sodium silicate and acetic acid. The pH was varied first by using different amounts of acetic acid, keeping the amount of sodium silicate and the total amount of solution constant, ) and secondly by using different amounts of silicate, keeping the ratio of silicate to acetic acid constant and the total volume of solution constant. When reading the literature I found that there was some confusion in terminology. In general, the terms "colloidal silicic acid" and "sol of hydrated silica" were used to refer to fluid mixtures containing hydrated silica. The term " silicic acid gel " was used to designate the gel after it had set. The term "silica gel" was used to designate the harder, partially dehydrated gel.
Kunes, Ella Rose, "The effect of pH on the setting of silicic acid gels" (1958). Honors Theses. 2229.