The effect of microwave and hydrothermal treatments on the properties of hydrotalcite

详细信息    查看全文

• 作者：S. Zadaviciute ; K. Baltakys ; A. Bankauskaite
• 关键词：Hydrothermal synthesis ; Microwave synthesis ; Hydrotalcite ; Solid ; state sintering ; Mg/Al spinel ; type compounds
• 刊名：Journal of Thermal Analysis and Calorimetry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：127
• 期：1
• 页码：189-196
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Physical Chemistry; Analytical Chemistry; Polymer Sciences; Inorganic Chemistry; Measurement Science and Instrumentation;
• 出版者：Springer Netherlands
• ISSN：1588-2926
• 卷排序：127

文摘

In this work, a comparative study of the application of direct microwave or hydrothermal synthesis for obtaining hydrotalcite from solid initial materials and the effect of these treatments (200 °C, 1–3 h) on the thermal stability of formed compounds were investigated. The molar ratios of primary mixtures Mg/Al were equal to 1 and 2, while the water/solid ratio was maintained to 10.0. It was determined that the microwave treatment was suitable for the direct synthesis of hydrotalcite, although the intensities of diffraction maximums characteristic to this compound were decreased under all experimental conditions. Furthermore, it was examined that, after 3 h of isothermal curing, the highest crystallinity of hydrotalcite was obtained. It should be noted that, in a case of microwave synthesis, the crystallite size of hydrotalcite varied in a 33.89–38.50 nm range, while, in a case of hydrothermal treatment, in a 40.06–52.45 nm region. Moreover, the method used for the synthesis of the latter compound did not influence the formation sequence of compounds during solid sintering (575 and 1000 °C, 1 h). In both cases, at 575 °C temperature, MgO and Al₂O₃ were formed, while at 1000 °C—magnesium and aluminium spinel-type compounds, which have a similar chemical nature, were obtained. The synthetic and calcined products were characterized by XRD, STA and SEM analyses.