Lightweight and highly hydrophobic silica aerogels dried in ambient pressure for an efficient oil/organic solvent adsorption

Çok, Selay Sert; Koç, Fatoş; Gi̇zli̇, Nilay

doi:10.1016/j.jhazmat.2020.124858

Cited by 74 publications

(37 citation statements)

References 40 publications

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“…In addition, they exhibit high thermal stability, resistance to water and open fire, and are biologically friendly, which makes them ideal PTM materials. Although various precursors have been used to synthesize silica aerogels, such as sodium silicates, tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), and methyltrimethoxysilane (MTMS), sodium silicates are the most widely used precursors for the mass production of silica aerogels − because they are much cheaper than other silica precursors, and the involvement of organic solvents can be avoided. Nevertheless, ion-exchange for sodium silicate should be carried out, which consumes a large amount of water and lengthens the production cycle time.…”

Section: Resultsmentioning

confidence: 99%

Superhydrophobic Silica Aerogels and Their Layer-by-Layer Structure for Thermal Management in Harsh Cold and Hot Environments

Liu

Shan

et al. 2021

ACS Nano

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Personal thermal management (PTM) materials have recently received considerable attention to improve human body thermal comfort with potentially reduced energy consumption. Strategies include passive radiative cooling and warming. However, challenges remain for passive thermal regulation of one material or structure in both harsh hot and cold environments. In this work, silica aerogels derived from sodium silicate were prepared through a solvent-boiling strategy, where hydrophobization, solvent exchange, sodium purification, and ambient pressure drying (HSSA) proceeded successively and spontaneously in a one-pot process. This strategy leads to the synthesis of superhydrophobic silica aerogels with extremely low energy consumption without out the use of an ion-exchange resin or low surface tension solvents. Silica aerogels possess a high specific surface area (635 m2/g), high contact angle (153°), and low thermal conductivity (0.049 W/m K). A layer-by-layer (LBL) structure including the silica aerogel layer and an extra phase change material layer was designed. The structure demonstrates dual-functional thermal regulation performance in both harsh cold (−30 °C) and hot (70 °C) environments, where the time to reach equilibrium is postponed, and the inner temperature of the LBL structure can be kept above 20 °C in harsh cold environments (−30 °C) and below 31 °C in harsh hot environments (70 °C). A proof-of-concept experimental setup to simulate the illumination of sunlight also proved that the inside temperature of a model car protected by the LBL structure was below 28 °C, while the outside temperature was 70 °C. In addition, these results are well supported by theoretical COMSOL simulation results. The findings of this work not only provide an eco-friendly approach to synthesize silica aerogels but also demonstrate that the LBL structure is a robust dual-functional PTM system for thermal regulation in both harsh hot and cold environments.

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Section: Resultsmentioning

confidence: 99%

Superhydrophobic Silica Aerogels and Their Layer-by-Layer Structure for Thermal Management in Harsh Cold and Hot Environments

Liu

Shan

et al. 2021

ACS Nano

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“…Meanwhile, hydrophobic SAs can easily be infiltrated by oil with low surface tension values, which is in favor of adsorption for oil. For example, Selay et al 189 prepared different surface-modified SAs to adsorb oil. The TMCS, as a surface-modified silane, endowed SAs with the highest surface area value (798 m 2 g −1 ) and superhydrophobicity ( θ = 152°).…”

Section: Applications Of Sasmentioning

confidence: 99%

Research progress and applications of silica-based aerogels – a bibliometric analysis

Zhu

Zhang³

et al. 2022

RSC Adv.

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“…Aerogel has several forms in practical applications where powder is the primary and widely used form. 26,36 In paerticular, the aerogel powder can be incorporated into organic or polymer materials and form inorganic−organic composites, which effectively improve the mechanical, hydrophobic, and fire-proof performance due to the heat-resistant and hydrophobic nature of silica aerogel (SA). 37,38 Some researchers have introduced SA particles into the PVA solution for direct drying, effectively increasing the flame retardant and thermal insulation properties of PVA while retaining the aerogel voids.…”

Section: Introductionmentioning

confidence: 99%

Green Preparation of Thermal-Insulative, Flame Retardant, and Hydrophobic Silica Aerogel Reinforced Poly(vinyl alcohol) Composites

Duan

Gao

Dong

et al. 2022

ACS Appl. Polym. Mater.

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Here, we developed silica aerogel/poly(vinyl alcohol) (PSG) composites by dispersing silica aerogel (SA) particles in poly(vinyl alcohol) (PVA) aqueous solution containing glass fibers (GF) and then experiencing directional freezing, freezing–drying, and thermal cross-linking processes. The microstructure, mechanical, thermal, flame retardancy, and hydrophobicity of the composites were investigated. The results show that SA and GF are uniformly distributed in the anisotropic PVA network and SA nanopores are preserved, forming a multistage pore structure with interwoven micrometer-scale PVA and nanoscale SA. The thermal cross-linking at 180 °C results in the obvious reduction of the −OH groups and the production of the −C–O–C group. The composites exhibit excellent mechanical strength under multiple compressive cycles and maintain structural integrity under high pressure (75000 times its own weight). With the low thermal conductivity (35.63 mW/(m·K)) and low density (0.131 g/cm3), the composites show excellent thermal insulation on cold (−75 °C) and hot (150 °C) plates. The composites possess flame retarding properties, with an HRR of 146.48 kW/m2. The water contact angle of up to 135° allows the composites to easily resist stains. This study provides a purely green method to prepare PVA composites with thermal insulation, flame retardant, and hydrophobic properties for industrial applications.

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Lightweight and highly hydrophobic silica aerogels dried in ambient pressure for an efficient oil/organic solvent adsorption

Cited by 74 publications

References 40 publications

Superhydrophobic Silica Aerogels and Their Layer-by-Layer Structure for Thermal Management in Harsh Cold and Hot Environments

Superhydrophobic Silica Aerogels and Their Layer-by-Layer Structure for Thermal Management in Harsh Cold and Hot Environments

Research progress and applications of silica-based aerogels – a bibliometric analysis

Green Preparation of Thermal-Insulative, Flame Retardant, and Hydrophobic Silica Aerogel Reinforced Poly(vinyl alcohol) Composites

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