Ambient-Dried Silica Aerogel Powders Derived from Coal Gangue by Using One-Pot Method.

Jian Wei,Hao Sun,Pinghua Zhu

doi:10.3390/ma15041454

Abstract

In this paper, we report a new and convenient method for the synthesis of insulating aerogel by recycling solid waste coal gangue, which can reduce the industrial production cost of silica aerogels and realize high value-added utilization of solid waste. Sodium silicate was prepared from a cheap industrial waste coal gangue as the precursor for silica aerogels, which was used for silica wet gel preparation by a one pot method; this method of solvent exchange/surface modification was carried out quickly by mechanical stirring process, and the wet gels derived from coal gangue were dried under ambient pressure condition. A high surface area (~748 m2/g) nanostructured aerogel with a 3D open porous microstructure was synthesized, which exhibits a low density (~0.18 g/cm3) and a superior thermal insulation performance (~0.033 W·m−1·K−1). More significantly, the synthetic yield of silica aerogel powder by recycling coal gangue can reach 92%.

Highlights

Silica aerogel is a non-crystalline material formed by nanoparticle aggregation and air as a dispersing medium, which has excellent properties such as low density, low thermal conductivity, large specific surface area and high porosity [1,2,3,4,5]
In order to dispose of these disadvantages, it is clear that the gels must be synthesized by a cheaper silicon precursor, modified by a simplified modification process and dried under ambient pressure
The content of C in coal sample was less than 15% wt.; Table 1 and Figure 1 show the elemental and mineral analysis results of coal gangue samples by X-ray fluorescence (XRF) and powder X-ray diffraction (XRD), respectively

Summary

Introduction

Silica aerogel is a non-crystalline material formed by nanoparticle aggregation and air as a dispersing medium, which has excellent properties such as low density, low thermal conductivity, large specific surface area and high porosity [1,2,3,4,5]. These features give it great potential for application in the fields of heat science, optics and catalysts. Despite the development of ambient pressure drying, expensive precursor materials and complex surface chemical modification processes still limit its large-scale industrial production [8,9].

Methods

Results

Conclusion