Abstract

A low-cost and simple method was proposed to synthesize SiO₂–Al₂O₃ composite aerogel from fly ash by alkali fusion-acid leaching-ambient pressure drying process just in 3 days for the first time. The effect of the leaching solution’s pH value upon micro-structure and properties of the as-prepared SiO₂–Al₂O₃ composite aerogel was intensively studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N₂ adsorption-desorption, and Fourier transform infrared spectrometry. The as-formed SiO₂–Al₂O₃ aerogel possessed high specific surface area (abbreviated as SSA) of 800 m²/g when the pH value was controlled at 2.7–3.1 (almost up to 900 m²/g at pH = 2.7). Meanwhile, the aerogel exhibited good thermal stability. After calcination at 900 °C for 2 h, the aerogel still remained an amorphous structure with a SSA of 77.88 m²/g. In addition, the related formation mechanism was also discussed.

中文翻译：

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用粉煤灰合成SiO 2 -Al 2 O 3复合气凝胶：一种低成本且简便的方法

抽象的

提出了一种低成本，简单的方法，首次用碱熔融-酸浸-环境压力干燥法在3天内首次从粉煤灰中合成了SiO ₂ -Al ₂ O ₃复合气凝胶。通过扫描电子显微镜，透射电子显微镜，X射线衍射，N ₂吸附-脱附对浸出液pH值对制备的SiO ₂ -Al ₂ O ₃复合气凝胶的微观结构和性能的影响进行了深入研究。，以及傅立叶变换红外光谱。形成的SiO ₂ -Al ₂ O ₃当pH值控制在2.7-3.1时，气凝胶具有800 m ² / g的高比表面积（缩写为SSA）（在pH = 2.7时，几乎高达900 m ² / g）。同时，气凝胶表现出良好的热稳定性。在900°C下煅烧2 h后，气凝胶仍保持无定形结构，SSA为77.88 m ² / g。此外，还讨论了相关的形成机理。