Mesoporous silica–alumina aerogels with high thermal pore stability through hybrid sol–gel route followed by subcritical drying

Preparation of Silica-Alumina Nanoparticles via Blast-Furnace Slag Dissolution in Low-Concentration Acetic Acid for Carbonation

“…Moreover, since the secondary particles are not well-dispersed, it is difficult to determine the sizes of these particles. The specific surface area of our nanoparticles was determined to be 264 m 2 /g, which is comparable to that of nanoparticles (25 mol % Al) synthesized using an organic precursor [18]. These particles exhibit a bimodal pore-size distribution, as displayed in Figure 8.…”

“…The peak at 3300 cm −1 is ascribed to OH vibrations resulting from the hydroxylation of the nanoparticle surfaces by absorbed water, which may catalyze the aggregation of the primary particles. The aluminum ions that form Si-O-Al bonds The specific surface area of our nanoparticles was determined to be 264 m 2 /g, which is comparable to that of nanoparticles (25 mol % Al) synthesized using an organic precursor [18]. These particles exhibit a bimodal pore-size distribution, as displayed in Figure 8.…”

“…In BFS, a characteristic peak at 900 cm −1 is evident, which is assigned to the asymmetric and symmetric Si-O stretching vibrations [17]. In the silica-alumina nanoparticles, a characteristic Si-O-Si vibration peak at 1040 cm −1 is clearly evident, along with shoulders on both the higher and lower sides of the band that indicate the presence of Si-O-Al bonds [18,21]. The peak at 3300 cm −1 is ascribed to OH vibrations resulting from the hydroxylation of the nanoparticle surfaces by absorbed water, which may catalyze the aggregation of the primary particles.…”

“…Aging was introduced not only to structurally arrange the Si and Al, but also to oxidize soluble Fe(II) to reddish Fe(III). Shrinkage and stiffness of the gel was also controlled during both aging and drying steps, which are the most important in sol-gel processes [18]. The silica-alumina nanoparticles dried at ambient pressure were characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FT-IR), field-emission scanning electron microscopy (FE-SEM), field-emission transmission electron microscopy (FE-TEM), mercury porosimetry, and nuclear magnetic resonance (NMR) techniques.…”

Adsorption and desorption performance of benzene over hierarchically structured carbon–silica aerogel composites

“…Standeker et al [11] found that silica aerogels modified with methyltrimethoxysilane or trimethylethoxysilane exhibited high adsorption capacities for toxic organic compounds from water, which were from 15 to 400 times higher as compared with granulated active carbon. Traditional silica aerogels preparation approaches involve supercritical drying process to avoid capillary stress and related drying shrinkage, whereas the supercritical drying process is energy intensive, expensive and dangerous [14]. To overcome these disadvantages of traditional supercritical aerogel process, a new ambient pressure drying process technique has been developed, making the manufacture and application of silica aerogels in large scale possible [15].…”