Characterization and comparison of uniform hydrophilic/hydrophobic transparent silica aerogel beads: skeleton strength and surface modification

Abstract

Hydrophilic mesoporous sodium silicate-based silica aerogel beads were produced by skeleton improvement of wet silica beads by ambient pressure drying. This preparation method is suitable for economic and large-scale industrial production of silica aerogel beads. AbstractSilica aerogel is a kind of good adsorbents due to the large surface areas and chemical stability. However, its inherent poor mechanical properties and hydrophobicity limited applications in water treatment. To improve the adsorption performance of silica aerogel, uniform transparent hydrophilic mesoporous silica 10 aerogel beads with highly degree of sphericity were synthesized through a facile aging immersion and ambient pressure drying route. The designed hydrophilic silica aerogel beads possessed the mesopores, mean diameter of approximately with the average pore size of 12.51 nm, the specific surface area of 582.52 m 2 g -1 , and the pore volume of 1.46 cm 3 g -1 . For comparison, hydrophilic silica aerogel beads without skeleton improvement and hydrophobic silica aerogel beads were also obtained, respectively. The 15 synthesized novel hydrophilic silica aerogel beads displayed a significantly improved adsorption performance with a favorable dye absorption capacity, superior to that of previously systhesised silicabased aerogel beads materials. This study demonstrates a facile and low-cost route toward transparent silica aerogel beads with macroscopic beads structures, which can be used as adsorbents, catalytic supports or the template to synthesize novel functional materials requiring high transmittance, high 20 surface area and effective mass transport. 65 which showed excellent physicochemical properties as well as remarkable adsorption performance effect.

Novel hydrophilic and hydrophobic amorphous silica: Characterization and adsorption of aqueous phase organic compounds

“…The need to recycle hydrophilic silicas may be considered irrelevant if the absence of functionalising agents and the use of cheaper precursors and synthesis make the production and waste management of these materials economically suitable for a single adsorption cycle, hence, removing regeneration costs and associated issues. Such gains may be achieved by using simpler, less energy intensive processing methods and low cost synthetic routes using ambient pressure drying are already known to produce silica aerogels, from waterglass, with excellent mechanical properties (Zong et al, 2015).…”

Hydrophilic and Hydrophobic Mesoporous Silica Derived from Rice Husk Ash as a Potential Drug Carrier

“…The longer hydrolysis-ageing time gave rise to the tendency to reduce silanol groups. FTIR spectra of the surface modification of MS with TMMS as demonstrated in Figure 5 b revealed the presence of Si–CH 3 at 2860 cm −1 [ 24 ]. The reduction of hydroxyl group intensities around 3300–3500 cm −1 also implied that some modification took place.…”

Preparation of transparent monolithic methylsilsesquioxane (MSQ) aerogels via ambient pressure drying

“…53 The high transparency of all the TEAH catalyzed aerogels indicated that the pores and particles present in the aerogels are regular and small enough. 54 In addition, the transmittance of all the TEAH catalyzed aerogels in UV region is close to zero indicating a strong scattering of short light waves.…”