Physicochemical properties of bamboo leaf aerogels synthesized via different modes of gelation

Abstract

Aerogels with ultralow silica concentration (3.5 %) was synthesized using bamboo leaf. The synthesis of aerogel was carried out in different pH to study the effect of gelation mechanisms on the properties of aerogel. Aerogel synthesized at acidic pH has generally exhibits more attractive properties, i.e. low shrinkage (24.3%), large specific surface area (547.2m2g−1), large pore volume (2.72cm3g−1) and low thermal conductivity (0.024Wm−1K−1). As comparison, the aerogel synthesized at basic condition has different properties, in which it has small pore volume (0.287cm3g−1) and pore size (11.44nm), large primary particles (6.69nm), small specific surface area (247.7m2g−1), low degree of fractality (6.69), strong absorption of water and relatively high thermal conductivity (0.0415Wm−1K−1). Properties of aerogels synthesized were also compared with aerogels synthesized using conventional TEOS precursor. The difference in the gelation mechanisms was discussed in detailed.