https://doi.org/10.1039/D0RA04497K
“WG, W and HAc were mixed with a volumetrical ratio of 6 : 33 : 1.2 under room temperature (25 °C) to form a water glass solution. The spherical silica gel was prepared by a “ball drop method”. The water glass solution was dropped into a dimethylsilicic oil bath at 70 °C to form the spherical silica gel. The spherical silica gel was washed with deionized water 3 times at 70 °C, and aged at 50 °C for 2 days. Then the spherical silica gel was transferred into an APTES/EtOH/W solution with a molar ratio of 1 : 24 : 3 for amine grafting at 50 °C. The spherical amine grafted silica gels with different grafting days were dried by VD to form the spherical amine grafted silica aerogels (SASAs), denoting as SASA-d, where d represents the grafting days. The spherical silica aerogel (SSA) without amine functionalization was prepared as control sample.”