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Influence of Support Type and Metal Loading in Methane Decomposition over Iron Catalyst for Hydrogen Production 下载免费PDF全文
Ahmed A. Ibrahim Ahmed S. Al‐Fatesh Wasim U. Khan Mostafa A. Soliman Raja L. AL Otaibi Anis H. Fakeeha 《中国化学会会志》2015,62(7):592-599
Natural gas resources, stimulate the method of catalytic methane decomposition. Hydrogen is a superb energy carrier and integral component of the present energy systems, while carbon nanotubes exhibit remarkable chemical and physical properties. The reaction was run at 700 °C in a fixed bed reactor. Catalyst calcination and reduction were done at 500 °C. MgO, TiO2 and Al2O3 supported catalysts were prepared using a co‐precipitation method. Catalysts of different iron loadings were characterized with BET, TGA, XRD, H2‐TPR and TEM. The catalyst characterization revealed the formation of multi‐walled nanotubes. Alternatively, time on stream tests of supported catalyst at 700 °C revealed the relative profiles of methane conversions increased as the %Fe loading was increased. Higher %Fe loadings decreased surface area of the catalyst. Iron catalyst supported with Al2O3 exhibited somewhat higher catalytic activity compared with MgO and TiO2 supported catalysts when above 35% Fe loading was used. CH4 conversion of 69% was obtained utilizing 60% Fe/Al2O3 catalyst. Alternatively, Fe/MgO catalysts gave the highest initial conversions when iron loading below 30% was employed. Indeed, catalysts with 15% Fe/MgO gave 63% conversion and good stability for 1 h time on stream. Inappropriateness of Fe/TiO2 catalysts in the catalytic methane decomposition was observed. 相似文献
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Functionalized nanoparticles based solid‐phase membrane micro‐tip extraction and high‐performance liquid chromatography analyses of vitamin B complex in human plasma 下载免费PDF全文
Imran Ali Umma Kulsum Zeid A. AL‐Othman Abdulrahman Alwarthan Kishwar Saleem 《Journal of separation science》2016,39(14):2678-2688
Iron nanoparticles were prepared by a green method following functionalization using 1‐butyl‐3‐methylimidazolium bromide. 1‐Butyl‐3‐methylimidazole iron nanoparticles were characterized using FTIR spectroscopy, energy dispersive X‐ray fluorescence, X‐ray diffraction, scanning electron microscopy and transmission electron microscopy. The nanoparticles were used in solid‐phase membrane micro‐tip extraction to separate vitamin B complex from plasma before high‐performance liquid chromatography. The optimum conditions obtained were sorbent (15 mg), agitation time (30 min), pH (9.0), desorbing solvent [water (5 mL) + methanol (5 mL) + sodium hydroxide (0.1 N) + acetic acid (d = 1.05 kg/L, pH 5.5), desorbing volume (10 mL) and desorption time (30 min). The percentage recoveries of all the eight vitamin B complex were from 60 to 83%. A high‐performance liquid chromatography method was developed using a PhE column (250 × 4.6 mm, 5.0 μm) and water/acetonitrile (95:5, v/v; pH 4.0 with 0.1% formic acid) mobile phase. The flow rate was 1.0 mL/min with detection at 270 and 210 nm. The values of the capacity, separation and resolution factor were 0.57–39.47, 1.12–6.00 and 1.84–26.26, respectively. The developed sample preparation and chromatographic methods were fast, selective, inexpensive, economic and reproducible. The developed method can be applied for analyzing these drugs in biological and environmental matrices. 相似文献
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Ultra high performance liquid chromatography with mass spectrometry method for the simultaneous determination of phenolic constituents in honey from various floral sources using multiwalled carbon nanotubes as extraction sorbents 下载免费PDF全文
Saikh Mohammad Wabaidur Yacine Badjah Hadj Ahmed Munir Saeed Obbed Nasser Mohamed AL‐Harbi Turki Mohammad AL‐Turki 《Journal of separation science》2015,38(15):2597-2606
An ultra high performance liquid chromatography with mass spectrometry method has been developed for the simultaneous separation, identification and determination of 22 phenolic constituents in honey from various floral sources from Yemen. Solid‐phase extraction was used for extraction of the target phenolic constituents from honey samples, while multiwalled carbon nanotubes were used as solid‐phase adsorbent. The chromatographic separation of all phenolic constituents was performed on a BEH C18 column using a linear gradient elution with a binary mobile phase mixture of aqueous 0.1% formic acid and methanol. The quantitation was carried out in selected ion reaction monitoring acquisition mode. The total amount of phenolic acids, flavonoids and other phenols in each analyzed honey was found in the range of 338–3312, 122–5482 and 2.4–1342 μg/100 g of honey, respectively. 4‐Hydroxybenzoic acid was found to be the major phenolic acid. The main detected flavonoid was chrysin, while cinnamic acid was found to be the major other phenol compound. The regeneration of solid phase adsorbent to be reused and recovery results confirm that the proposed method could be potentially used for the routine analysis of phenolic constituents in honey extract. 相似文献
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V. P. Antonova S. V. Kryukov A. P. Chubenko Yu. V. Shlyugaev A. L. Shepetov 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):843-846
Variations in cosmic rays are investigated on the basis of the Tien Shan neutron monitor data. The Earth’s electrical field
during snowfall, rain, and thunderstorm activity is considered as a modulating factor. It is established that the effect of
the electrical field on the monitor data becomes apparent at values exceeding 15–20 kV m−1 in the atmosphere of a thunderstorm. The response is as high as 1.5% for recorded particles with energies lower than 10 GeV. 相似文献
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A standard model is suggested to explore correlation features of two spatially separated optomechanical cavities. The cavities are coupled through the photon-hopping process. In particular, we investigate the generation of entanglement between mechanical resonators in the strong coupling regime and the two cavities are assumed to be driven by a coherent laser field. In order to quantify entanglement we use the logarithmic negativity. The analytical solutions are presented for the system in a parameter regime very close to the current experimental results. We show that in the presence of the photon hopping process between the cavities, the two mechanical resonators and the field modes can be entangled. This shows clearly that the entanglement can be transfer via radiation pressure of a photon hopping coupling from the intracavity photon-phonon entanglements to an inter-cavity photon-photon or phonon-phonon entanglement. 相似文献
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Manoj Kumar AL. Ramanathan Abhijit Mukherjee Ravi Sawlani Shyam Ranjan 《Isotopes in environmental and health studies》2019,55(3):254-271
Stable isotopes of water (δ2H, δ18O) and δ13CTIC were used as a tool to trace the recharge processes, natural carbon (organic and inorganic) source and dynamics in the aquifers of the central Gangetic basin, India. Stable isotope (δ2H, δ18O) record of groundwater (n?=?105) revealed that the groundwater of Piedmont was recharged by meteoric origin before evaporation, while aquifers of the older and younger alluvium were recharged by water that had undergone evaporation loss. River Ganges and its tributaries passing through this area have very little contribution in recharging while ponds play no role in the recharging of adjacent aquifers. The connectivity of shallow aquifers of aquitard formation (comprised of clay/sandy clay with thin patches of fine grey sand), i.e. 25–60?m below ground level (bgl) with the main upper aquifer (at a depth of >120?m?bgl) was found to be higher in older and younger alluvium. Negative values of δ13CTIC (median ?9.6 ‰; range ?13.2 to ?5.4 ‰) and high TIC (median 35?mM; range 31–46?mM) coupled with low TOC (median 1.35?mg/L; range 0.99–1.77?mg/L) indicated acceleration in microbial activity in the younger alluvium, especially in the active floodplain of river Ganges and its proximity. 相似文献
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A?Pires M?Nelson AL?Pozniak M?Fisher B?Gazzard F?Gotch N?ImamiEmail author 《Journal of immune based therapies and vaccines》2005,3(1):7