| Autor: |
Xiao, Anni, Jia, Caiyun, Fang, Xiaoxia, Zhao, Jiang, Zhang, Haijun |
| Předmět: |
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| Zdroj: |
New Journal of Chemistry; 3/14/2024, Vol. 48 Issue 10, p4473-4481, 9p |
| Abstrakt: |
Na2EDTA is an effective morphology regulator in preparing α-calcium sulfate hemihydrate (α-HH) with high mechanical strength, but its simultaneous effect on the phase transformation process and morphology evolution of α-HH is still unclear. This study finds that the addition of Na2EDTA from 0.00 to 1.40 mM dramatically prolongs the induction time and phase transformation time from 2 to 240 min and 118 to 480 min respectively, due to the complexation of Ca2+ and EDTA2− in solution while further increase to 2.20 mM doesn't continuously increase the induction time and phase transformation time. Meanwhile, the addition of Na2EDTA generates the morphology evolution of α-HH from fibrous to short columnar with an average aspect ratio from 31.5 to 1.7, resulting from the selective adsorption of EDTA2− on both the top and side faces of α-HH crystals where Ca2+ ions are distributed at different densities. This selective adsorption provides more details compared with the conventional understanding of EDTA2− adsorption focusing on the top faces. Altogether, this work gives a clear view of the relationship between Na2EDTA concentration and phase transformation and morphology evolution of α-HH, which contributes to providing theoretical guidance on preparing α-HH crystals with an appropriate phase transformation rate and ideal morphology. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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