Facile synthesis of ternary flexible silica aerogels with coarsened skeleton for oil–water separation

Abstract

Ternary flexible silica aerogels were synthesized using a facile sol–gel process without solvent exchange and surface modification using dimethyldiethoxysilane (DEDMS), methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) via ambient pressure drying. The skeleton morphology of the aerogels was precisely controlled by the DEDMS/TEOS molar ratio (D). The effect of the morphology of the aerogel skeleton on the mechanical properties and the adsorption capacity was investigated. As the D increased, the morphology of the aerogel skeleton gradually changed from a fragment structure to a coarsened structure, and finally to a chain-like structure. The prepared coarsened structure aerogel exhibited a low density of 0.095 g cm⁻³, a compressible amount reaching up to 78.2%, a Young's modulus as low as 14 kPa, a superhydrophobicity with a contact angle of 154.8° and an excellent adsorption capacity of 8.7–15.4 g g⁻¹. Furthermore, the outstanding recycling ability and corrosion resistance made the aerogels suitable for oil–water separation in corrosive environments.