JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Meng-En Li,Shui-Xiu Wang,Lin-Xuan Han,Wen-Jie Yuan,Jin-Bo Cheng,Ai-Ning Zhang,Hai-Bo Zhao,Yu-Zhong Wang
Polyurethane foam (PUF) is widely used in building insulation field but highly flammable. In an effort to develop an efficient way to reduce flammability and smoke release of PUF without sacrificing its inherent merits, a novel strategy has been proposed to decorate silica aerogels onto the surface of PUF to fabricate hierarchically porous SiO 2 /PUF composites. Due to the unique hierarchically porous structure, the resultant composites showed superior thermal insulation with a lower thermal conductivity of 0.0282 W/(m K). The introduction of silica aerogels also effectively improved the compressive strength, almost 220% of that of neat PUF. Notably, the SiO 2 /PUF composites were rendered self-extinguishing in vertical burning tests and had a high limiting oxygen index (LOI) value of 32.5%. Cone calorimetry (CC) tests revealed that the peak heat release rate (PHRR) and peak smoke production release (PSPR) of the SiO 2 /PUF composites were reduced by 40.4% and 45.6%, respectively. Particularly, the specific optical density (Ds) of the composites displayed as 55.7% reduction in the smoke density chamber tests, showing excellent smoke-suppression. The mechanism analysis suggested that a compact silica-rich hybrid barrier formed, preventing thermal degradation products and energy transfer during combustion. These results indicate SiO 2 /PUF composites have enormous potential as building insulation materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Xiaodong Wu,Jianwei Man,Sijia Liu,Shuntian Huang,Jiaxin Lu,Juxiang Tai,Ya Zhong,Xiaodong Shen,Sheng Cui,Xiangbao Chen
The applications of silica aerogels are restricted due to their intrinsic fragile property. Polymerization of di-isocyanates can be templated onto the mesoporous surface of the –NH 2 group modified silica clusters, resulting in the conformal crosslinked coating on surface of silica clusters. Aminopropyltriethoxysilane (APTES), as the silica co-precursor and amine group modification agent, is involved containing tetramethyl orthosilicate (TMOS) silica precursor, while hexamethylene diisocyanate (HDI) is incorporated as the polymer crosslinking agent. The effects of different amounts of APTES on the physicochemical properties of the resulting crosslinked aerogels are investigated. The results show that the optimized APTES/TMOS volume ratio can be determined at 0.5:1. The resulting optimal crosslinked silica aerogel possesses large BET specific surface area of 150.9 m 2 /g, low thermal conductivity of 0.037 W/(m·K), and the Young's modulus is as large as 18 MPa under strain of 4.2%, much higher than that in the previously published works. The polymerization reaction mechanism forming the polyurethane chains has also been proposed. In addition, the interactions between silica clusters and polymer chains are studied by molecular mechanics and molecular dynamics. The interactions are mainly dependent on non-bonding energy, and the electrostatic energy has decisive impact on the combination of silica clusters and polymer chains. The density field of C, H, N, O, and Si elements overlaps with each other, indicating that the polymer crosslinked silica aerogel maintains typical three-dimensional porous structure. The N element enriches in the region between silica clusters, further verifying the formation –CONH–(CH 2 ) 6 –CONH- polyurethane chains, which is actually responsible for the much enhanced mechanical property.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2023
·
IF 3.5
Yudi Duan,Lijuan Wang,Shiyu Li,Xiaofei Liu,Jinsheng Liang,Jiachen Liu,Xinhui Duan,Hui Liu
In this work, a kind of superhydrophobic silica aerogels was prepared at ambient pressure using tetraethoxysilane (TEOS) as precursor. Particularly, N-hexane was added in the solvent to modulation pore microstructure and effect on the insulation properties of samples were analyzed. It is discovered that when the volume ratio of N-hexane to TEOS is 1:2.24 the thermal conductivity of samples can reach the lowest of 0.012 W/m·K. Compared with that of samples no addition of N-hexane, the density is decreased, the theoretical average pore size increases and the total pore volume increases. Due to N-hexane it leads cross-linking between the sol particles stronger and inhomogeneous. Thus gelation process is speeded up resulting in a change in pore structure. Low density can reduce the solid-phase heat transfer, perfect pore microstructure reduces the contribution of gas-phase heat transfer, and only when the two aspects forms a suitable combination it can exhibit optimal thermal insulation performance.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Zai-Dong Shao,Ting-Ting Hu,J. Paul Chen,Qi-Jun Zhang,Peng Wu,Rui-Sang Liu,Jiang Lu,Xiao-Meng Ren,Yu-Ming Zheng
Gaseous ammonia (NH 3 ), a highly corrosive and toxic pollutant, poses significant risks to human health and the environment. This study addresses the challenge of trace NH 3 removal by synthesizing carboxylic acid-functionalized silica aerogels (CMSA-X) through a simple, cost-effective two-step grafting approach. The fabricated CMSA-4 aerogel exhibited a high -COOH group content (4.13 mmol·g −1 ) and a stable nanoporous structure, enabling reversible and highly selective adsorption for trace gaseous ammonia. It demonstrated exceptional adsorption capacity (3.90 mmol·g - 1 at 0.1 bar and 7.30 mmol·g -1 at 1.0 bar) and outstanding adsorption selectivity (selectivity coefficients of ∼43031 for NH 3 /N 2 and ∼2200 for NH 3 /CO 2 , respectively). The NH 3 -saturated CMSA-4 can be easily regenerated by low temperature treatment (393 K), and maintained 94% adsorption capacity after ten adsorption-desorption cycles. The superior dynamic adsorption capacities of 3.36 mmol·g - 1 under dry condition and 3.28 mmol·g - 1 under humid condition outperformed previously reported adsorbents. Field tests further confirmed its efficacy in removing trace NH 3 (2 ppm), achieving removal rates 1.6-3.8 times higher than commercial alternatives. In-situ diffusion infrared spectroscopy revealed that proton transfer caused OCO - NH 4 + formation is the key adsorption mechanism. This study provides a promising method to develop high-performance adsorbent for efficient trace NH 3 removal in environmental and industrial applications.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2019
·
IF 5.77
Hao Zhang,Fan Yang,Ruixi Bai,Zhigang Zhao,Chunqing Cai,Jianguo Li,Ying Ma
Thorium (Th) is an associated ore of rare earth metals that is radioactive and harmful to the environment, but it is also a potential nuclear fuel replacement for uranium. The separation of Th from rare earth elements (REEs) is of great importance in environmental governance and clean-energy development. In this work, a monolithic cerium (Ce) doped silica aerogel-like with flexibility was synthesized using a low consumption and rapid technique, and it was used in a continuous solid-phase extraction as an adsorbent for the selective separation of Th/REEs. The batch adsorption experiments showed that the adsorption efficiency of Th(IV) can be up to 96% when abnormally high levels of metal ions (20 ppm) exist. Under the same conditions, the adsorption efficiency of REEs is at a near-zero level, which demonstrates the great selective separation of Th/REEs for the aerogel-like. The results also indicated that Th(IV) could desorb from the adsorbent in weak acidic media, which is friendly to the environment. Therefore, the material has application prospects for the separation of Th/REEs and removal of radioactive contamination from the environment.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2019
·
IF 2.6
Zhuchao Yang,Huijun Yu,Xiaolei Li,Honghui Ding,Huiming Ji
A hyperelastic and hydrophobic silica aerogel has been prepared by using Vinyltriethoxysilane (VTES) and Methyltrimethoxysilane (MTMS) as the composite precursor. The effect of the VTES/MTMS molar ratio on the morphology of the VTES/MTMS-based aerogel has been investigated. The VTES/MTMS-based aerogel with a typical nano-porous structure exhibits a high surface area (321 m 2 /g), a low density (0.143 g·cm − 3 ) and low thermal conductivity (0.024 ± 0.003 W·m − 1 ·K − 1 ). The existence of methyl and vinyl groups is beneficial to enhancing the elasticities of aerogels. The MVTES5, with a VTES/MTMS molar ratio of 0.060, could bear a compressive strain of 55% and quickly recover to its original length after the stress is released. It is demonstrated that the partial replacement of the methyl with vinyl groups can greatly enhance the mechanical properties , and the compressive stress is 0.571 MPa. Furthermore, the VTES/MTMS-based aerogel exhibits hydrophobic properties with a contact angle of 146°.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2018
·
IF 2.488
Yan Luo,Zhi Li,Wei Zhang,Hui Yan,Yinfeng Wang,Ming Li,Qiong Liu
In this paper, using methyltrimethoxysilane (MTMS) as precursor, silica aerogels (SA) with excellent performance were synthesized within 10 h via APD without further surface modification and solvent exchange. The investigation was concentrated on three primary factors, including base catalyst, surfactant , and co-solvent system. The results indicated that NH 3 ·H 2 O concentration and the volume ratio of NH 3 ·H 2 O to MTMS were of great importance to the formation of particles, clusters, and pores. It was also obtained that the surfactant of CTAB influences the pore structure as well as thermostability of prepared aerogels significantly. Furthermore, an optimum volume ratio of EtOH/H 2 O in co-solvent system not only reduced the volume shrinkage but also enabled a good hydrophobicity of prepared SAs. Base on above, by adjusting the preparation parameters, the obtained SAs can exhibit the low density of 0.0968 g/cm 3 , low thermal conductivity of 0.037 W m −1 K −1 , contact angle as high as 144.7 ° and thermostability reaching up to 528.1 °C. Meanwhile, some specific performance of SAs, such as hydrophobicity, could be tailored, which will improve its applicability.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2017
·Vol. 10
·期 4
·435
·
IF 2.654
Qifeng Chen,Hui Wang,Luyi Sun
Silica aerogel microspheres based on alkali silica sol were synthesized using the emulsion method. The experimental results revealed that the silica aerogel microspheres (4–20 µm in diameter) were mesoporous solids with an average pore diameter ranging from 6 to 35 nm. The tapping densities and specific surface areas of the aerogel microspheres are in the range of 0.112–0.287 g/cm3and 207.5–660.6 m2/g, respectively. The diameter of the silica aerogel microspheres could be tailored by varying the processing conditions including agitation rate, water/oil ratio, mass ratio of Span 80: Tween 80, and emulsifier concentration. The effects of these parameters on the morphology and textural properties of the synthesized silica aerogel microspheres were systematically investigated. Such silica aerogel microspheres can be used to prepare large-scale silica aerogels at an ambient pressure for applications in separation and high efficiency catalysis, which requires features of high porosity and easy fill and recovery.Keywords:silica aerogel microspheres;emulsion method
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Xiang Li,Xiaoxiao Huang,Qingge Feng,Zheng Liu,Dongbo Wang,Dachao Ma,Lin Feng,Chen Zuo,Junyi Liu,Sinan Wang,Zhuoyan Huang,Xiaodie Cheng,Wanlin Ni
Some challenges exist in oil-water separation materials, including complex synthesis, high preparation costs, and weak recovery. Herein, the elastic and superhydrophobic silica aerogels/polyurethane sponges (SA/PUS) were prepared by fabricating silica aerogels (SA) on the skeleton of the cheap polyurethane sponges (PUS), through a simple dipping and sol-gel method under ambient pressure drying procedure. Importantly, boosted by the inorganic silicon precursors, the dense and rough coating by the functionalized SA on the surface was realized under environmentally friendly modification and adhesive-free, which contributed to the superhydrophobicity of the SA/PUS. The splendid thermal stability allowed the SA/PUS to maintain a hydrophobic property at high temperatures (over the flash point of the oil in this work). The excellent adsorption performance was confirmed on both oil/water mixture (11 times own weight) and oil-in-water emulsion (separation efficiency up to 98.78%). Moreover, the elastic SA/PUS could recover from large-scale deformations owing to the combination with the PUS with a three-dimensional skeleton, which improved the mechanical strength and overcome the limitation of the brittle SA. The recovery efficiency of the adsorbed oil from oil/water mixture was 92.70% and nearly no decline in reusing by simple mechanical squeezing. Such excellent performance was also demonstrated in oil-in-water emulsion. Advantages (superhydrophobic and lipophilic, elastic, and thermal stability, etc.) of the SA/PUS, which were prepared by simple synthesis, bring application potential for treating automobile maintenance sewages and expanded applications, including separation and recovery of oil from oily wastewater circularly and uptake of high-value-added hydrophobic molecules in biomass or other processes.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Kangwei Li,Song He,Chunhua Du,Saiping Guo,Yajun Huang
Flexible Silica aerogel has a broad application prospect in the field of oil-water separation due to its low density and high porosity. However, its poor mechanical properties limit its application and it is a challenge to improve its mechanical properties while maintaining its excellent oil absorption capacity. In this work, we add silica sol to the silica source system formed by vinyltrimethoxysilane (VTMS) and vinylmethyl dimethoxysilane (VMDMS) to prepare silica sol-reinforced flexible silica aerogels by ambient pressure drying. The introduction of silica sol provides more -OH groups that can be used as condensation sites. The hydrolysis products of VTMS and VMDMS undergo dehydration condensation reaction with these exposed -OH groups and co-polymerize, resulting in a more robust three-dimensional porous structure. Silica sol- reinforced vinyl flexible silica aerogel is prepared with excellent mechanical properties. Its maximum strain can reach 80 % in 10 compression-decompression cycles without destroying its structure. Its hydrophobic angle was 145.7 °. Most particularly, compared to conventional flexible aerogel,when the silica sol-reinforced vinyl flexible silica aerogel is used in oil-water separation applications, it does not need to be dried after absorbing oil but only mechanically squeezed to expel the absorbed organic solvent. It can be reused hundreds of times, which greatly improves the efficiency of oil-water separation.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Analytical Methods
·
2020
·Vol. 12
·期 33
·4123-4129
·
IF 2.596
Wei Liu,Zihao Song,Yifan Zhao,Yu Liu,Xuan He,Sheng Cui
Sensitive and reliable methods for explosives detection are of significance in homeland security due to the serious threats of explosives in terrorist attack events. However, such suitable sensors are still rare. Herein, porous silica aerogels decorated with silver nanoparticles (SiO2–Ag hybrids) were prepared and applied as a flexible SERS substrate for ultrasensitive explosives detection. It is worth noting that the silica aerogel we prepared had good flexibility compared with traditional silica aerogels, which effectively avoided structural damage during sample collection. Also, because of excellent adsorption performance provided by the silica aerogel, trace explosive 3-nitro-1,2,4-triazol-5-one (NTO) could be enriched and realized by label-free detection. Combined with the plasma enhancement provided by Ag NPs decorated around these porous aerogels, the limit of detection for explosive NTO was as low as 7.94 × 10−10 M. As far as we know, this SiO2–Ag hybrid SERS substrate was firstly used for the detection of explosives. It presented good sensitivity and reproducibility for analyte sensing. Most importantly, this is a label-free method for trace explosives detection and has a good application prospect in homeland security.
研究领域:
材料科学
·
分析化学
·
公共安全
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POROUS MATERIALS
·
2017
·Vol. 25
·期 4
·1027-1034
·
IF 1.624
Chen Yongquan,Yang Haitao,Nie Jun,Zhu Xiaoqun
Highly flexible silica aerogels were fabricated by using 2-(3-(triethoxysilyl)propylcarbamoyloxy) ethyl acrylate (TESEA), methyltriethoxysilane (MTES), and polydimethylsiloxane (PDMS) as co-precursors through photopolymerization and sol–gel process, then followed by ambient pressure drying. Attributing to photolysis of the photoacids generators, the radical and Brönsted acid (HSbF 6 ) were generated simultaneously under irradiation. The radical initiated the photopolymerization of acrylate which induced the gelation and fixed the shape of the gel quickly, the acid allowed the sol–gel process occurring gradually. Due to the enhancement of the polymer, the strength of aerogels was improved. The aerogels had low density (~ 0.098 g/cm 3 ), high porosity (~ 94.8%), high flexibility and high elastic recovery. Moreover, the silica aerogels have hydrophobic and oleophilic properties, which endows them with an ability of oil water separation.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）