Mixed-metal oxide aerogels for oxidation of volatile organic compounds

Hair, L.M.; Coronado, Paul R; Reynolds, John G.

doi:10.1016/s0022-3093(00)00077-6

Cited by 11 publications

(4 citation statements)

References 34 publications

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“…23 Because of this, some alkoxide-based recipes need to be fabricated in a glove box. 24 Alkoxides are not commercially available for most transition metals; those that are available are relatively expensive. Many alkoxide recipes require hours of mixing in order to dissolve the alkoxide, hydrolyze it, and condense the resulting hydroxides.…”

Section: Introductionmentioning

confidence: 99%

Epoxide-assisted alumina aerogels by rapid supercritical extraction

Juhl

Dunn

Carroll

et al. 2015

Journal of Non-Crystalline Solids

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Aerogels offer a potential alternative to noble metals that could reduce both the cost and environmental impact associated with catalytic converter production. The environmental impact of the production of aerogel catalysts could be further reduced by using a rapid supercritical extraction (RSCE) technique, which reduces the time and solvent waste associated with aerogel preparation. Alumina aerogels, which have shown activity in catalyzing exhaust processing reactions, were prepared using an epoxide-assisted gelation technique with RSCE processing in a contained mold in a hydraulic hot press. Samples were characterized by FTIR, XRD, SEM, EDX, nitrogen adsorption porosimetry and pycnometry. Solvent characterization by GC-MS headspace analysis shows that excess propylene oxide and chloropropanol products of an irreversible epoxide ring-opening reaction are present in the alumina gel following gelation, but can be removed via solvent exchange. Alumina aerogels with surface areas as high as 790 m 2 /g and bulk densities as low as 0.05 g/mL were prepared. Preliminary characterization of these aerogels, utilizing a catalytic test bed and a simulated emissions gas blend, demonstrates that they have moderate ability for removal of hydrocarbons, carbon monoxide and nitrogen oxide.

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Section: Introductionmentioning

confidence: 99%

Epoxide-assisted alumina aerogels by rapid supercritical extraction

Juhl

Dunn

Carroll

et al. 2015

Journal of Non-Crystalline Solids

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“…For comparison, to demonstrate the oil a nity of the CF 3 -functionalized aerogel, a normal silica aerogel was prepared (Hair et al, 2000) without the CF 3 -functionality and tested in the same manner, above. Only 0.06 g of oil were recovered, giving an O/A of , 0.1 for saturation.…”

Section: Oil Absorbing Behaviormentioning

confidence: 99%

Hydrophobic Aerogels for Oil-Spill Cleanup? Intrinsic Absorbing Properties

Reynolds¹

2001

Energy Sources

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A hydrophobic , CF 3 -functionalized silica aerogel has been applied to water-oil mixtures to determine oil absorbing capacity of the solid aerogel. Preliminary tests on Prudhoe Bay crude oil mixed with salt water, using the aerogel in powder form, show three regimes for absorbing based on oil to aerogel wt ratios ( O/A):1) all oil is absorbed and the aerogel is dry, O/A 0± 3.5; 2) all oil is involved in an oil± aerogel± water emulsion, O/A 4.6± 14; and 3) some oil is involved in an oil± aerogel± water emulsion, but free-phase oil is seen, O/A . 16. For comparison, a silica aerogel that has not been functionalized shows maximum absorbing capacity without the appearance of free-phase oil at O/A , 0.1. Separation and extraction studies showed good aerogel recovery and moderate oil recovery. Extraction studies at O/A of 2.3 showed that the aerogel could be reused at least two times. Infrared studies show that the oil recovered from the absorbing material and the starting oil are structurally similar.These results indicate that the CF 3 -functionalized aerogel as a powder has the potential of cleanly separating oil from oil± water mixtures up to 14 times the weight of the aerogel.

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“…Furthermore, most of the physical size of pores is small [10]. High thermal stability [11] and biocompatibility [12] are other advantages of silica xerogel, which makes it attractive for catalytic and bioapplications.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Fe₂O₃/SiO₂ Nanocomposite by FESEM and TEM

Ang

Yaacob

Nurdin

2013

Journal of Nanomaterials

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Superparamagnetic maghemite nanoparticles were synthesized using Massart’s procedure. Nanocomposites that consist of the synthesized maghemite nanoparticles and silica were produced by dispersing the as-synthesized maghemite nanoparticles into the silica xerogel prepared by sol-gel technique. The system was then heated for 3 days at 140°C. The structure, morphology, and texture of the system were analysed by FESEM and TEM. The result from FESEM showed that the silica gel forms a network structure, which contained numerous pores, with an average pore size of 15 nm. EDX line profile analysis was carried out, and the result indicated that the embedded particles were iron oxide. EELS showed the presence of Fe-L2signal, which confirmed the presence of iron oxide particles within the silica matrix. The average diameters were 5.0 nm for as-synthesized maghemite nanoparticles and 4.4 nm for the embedded maghemite nanoparticles in silica xerogel matrix. The embedded maghemite nanoparticles in nanocomposite also showed a narrower distribution compared to as-synthesized particles. The magnetization values at 10 kOe applied field,Ms10 kOe, were 9.53 emu/g and 1.79 emu/g for as-synthesized and embedded nanoparticles, respectively. A reduction in average crystallite size was observed for the dispersed maghemite particles after formation of the nanocomposite indicating a slight dissolution of maghemite nanoparticles in silica gel.

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Mixed-metal oxide aerogels for oxidation of volatile organic compounds

Cited by 11 publications

References 34 publications

Epoxide-assisted alumina aerogels by rapid supercritical extraction

Epoxide-assisted alumina aerogels by rapid supercritical extraction

Hydrophobic Aerogels for Oil-Spill Cleanup? Intrinsic Absorbing Properties

Investigation of Fe₂O₃/SiO₂ Nanocomposite by FESEM and TEM

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Mixed-metal oxide aerogels for oxidation of volatile organic compounds

Cited by 11 publications

References 34 publications

Epoxide-assisted alumina aerogels by rapid supercritical extraction

Epoxide-assisted alumina aerogels by rapid supercritical extraction

Hydrophobic Aerogels for Oil-Spill Cleanup? Intrinsic Absorbing Properties

Investigation of Fe2O3/SiO2 Nanocomposite by FESEM and TEM

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Investigation of Fe₂O₃/SiO₂ Nanocomposite by FESEM and TEM