フライアッシュを原料としたH^+型ジオポリマーの作製とイオン交換特性

抄録

H^+-form geopolymer powder was prepared by grinding a Na^+-form geopolymer hardened paste and processing it with sulfuric acid. At pH 7, the extent of cation exchange with Na^+ and K^+ ions of the H^+-form geopolymer powder was one-fourth of that of the original Na^+-form geopolymer at the same pH. The ion-exchange capacity of the H^+-form geopolymer powder showed pH dependence, that is, a tendency to increase with increasing pH. Additionally, we observed that the H^+-form geopolymer powder adsorbed Na^+ ions from and lowered the pH of the hardened cement paste. However, in solution at pH 12.5, a part of the Si component of the H^+-form geopolymer powder was leached out. It was thus confirmed that other alkaline-adsorption mechanisms, by which the leached Si-component reacts with the alkaline component of the cement paste, are at work, and therefore, they need to be considered in addition to the cation-exchange reaction in order to understand completely the behavior of the H^+-form geopolymer in cement paste.