In this work, we report on a novel sodium dodecyl sulfate (SDS)-assisted magnesium oxide (MgO)-based porous adsorbent synthesized by hydrothermal method for intermediate CO2 capture. For industrial ...MgO, its CO2 adsorption capacity is normally less than 0.06 mmol g−1, with a specific surface area as low as 25.1 m2 g−1. Herein, leaf-like MgO nanosheets which exhibited a disordered layer structure were fabricated by the introduction of SDS surfactants and the control of other synthesis parameters. This leaf-like MgO adsorbent showed an excellent CO2 capacity of 0.96 mmol g−1 at moderate temperatures (~300 °C), which is more than ten times higher than that of the commercial light MgO. This novel mesoporous MgO adsorbent also exhibited high stability during multiple CO2 adsorption/desorption cycles. The excellent CO2 capturing performance was believed to be related to its high specific surface area of 321.3 m2 g−1 and abundant surface active adsorption sites. This work suggested a new synthesis scheme for MgO based CO2 adsorbents at intermediate temperatures, providing a competitive candidate for capturing CO2 from certain sorption enhanced hydrogen production processes.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Technical zeolite bodies with additional porosity have been prepared with the intention to improve effective diffusivity. The latter has been assessed by three different techniques, combining a ...simple one as uptake measurements (thermogravimetric analysis) to a more sophisticated pulsed-field gradient-nuclear magnetic resonance method. Inverse gas chromatography provided further complement to the aforementioned techniques by mimicking realistic operating conditions (temperature and flow). The three methods assessed an enhancement in the effective diffusivity for the samples where mesopores or macropores were created. Useful insights concerning the interactions between the binder and the zeolite were gained, showing a strong impact on the effective diffusivity within the catalyst body.
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IJS, KILJ, NUK, PNG, UL, UM
A reverberation-mapping program on NGC 4395, the least luminous known Seyfert 1 galaxy, undertaken with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope yields a measurement of ...the mass of the central black hole M sub(BH) = (3.6 c 1.1) x 10 super(5) M sub( ). The observations consist of two visits of five orbits each, in 2004 April and July. During each of these visits, the UV continuum varied by at least 10% (rms), and only C IV l1549 showed corresponding variations large enough to reliably determine the emission-line lag, which was measured to be of order 1 hr for both visits. The size of the C IV-emitting region is about a factor of 3 smaller than expected if the slope of the broad-line region radius-luminosity relationship is identical to that for the Hb emission line. NGC 4395 is underluminous even for its small black hole mass; the Eddington ratio of 61.2 x 10 super(-3) is lower than that of any other active galactic nucleus for which a black hole mass measurement has been made by emission-line reverberation.
Carbon dioxide(CO2) capture using magnesium oxide(MgO)-based adsorbents at intermediate temperatures has been regarded as a very prospective technology for their relatively high adsorption ...capacity,low cost, and wide availability. During the past few years, great effort has been devoted to the fabrication of molten salts-modified MgO-based adsorbents. The extraordinary progress achieved by coating with molten salts greatly promotes the CO2 capture capacity of MgO-based adsorbents. Therefore, we feel it necessary to deliver a timely review on this type of CO2 capturing materials, which will benefit the researchers working in both academic and industrial areas. In this work, we classified the molten saltsmodified MgO adsorbents into four categories:(1) homogenous molten salt-modified MgO adsorbents,(2) molten salt-modified double salts-based MgO adsorbents,(3) mixed molten salts-modified MgO adsorbents, and(4) molten salts-modified MgO-based mixed oxides adsorbents. This contribution critically reviews the recent developments in the synthetic method, adsorption capacity, reaction kinetics, promotion mechanism, operational conditions and regenerability of the molten salts-modified MgO CO2 adsorbents. The challenges and prospects in this promising field of molten salts-modified MgO CO2 adsorbents in real applications are also briefly mentioned.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Green methanol is a viable alternative for the storage of hydrogen and may be produced from captured anthropogenic sources of carbon dioxide. The latter was hydrogenated over Cu-ZnO catalysts ...supported on an aluminum fumarate metal-organic framework (AlFum MOF). The catalysts, prepared via slurry phase impregnation, were assessed for thermocatalytic hydrogenation of CO2 to methanol. PXRD, FTIR, and SBET exhibited a decrease in crystallinity of the AlFum MOF support after impregnation with Cu-Zn active sites. SEM, SEM-EDS, and TEM revealed that the morphology of the support is preserved after metal loading, where H2-TPR confirmed the presence of active sites for hydrogen uptake. The catalysts exhibited good activity, with a doubling in Cu and Zn loading over the AlFum MOF, resulting in a 4-fold increase in CO2 conversions from 10.8% to 45.6% and an increase in methanol productivity from 34.4 to 56.5 gMeOH/Kgcat/h. The catalysts exhibited comparatively high CO selectivity and high yields of H2O, thereby favoring the reverse water-gas shift reaction. The selectivity of the catalysts towards methanol was found to be 12.9% and 6.9%. The performance of the catalyst supported on AlFum MOF further highlights the potential use of MOFs as supports in the heterogeneous thermocatalytic conversion of CO2 to value-added products.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A series of nickel‐decorated covalent organic frameworks, NiCl@RIO‐12, were prepared using the post‐synthetic modification strategy, that is, by reacting NiCl2 with pristine RIO‐12 under alkaline ...conditions. Interestingly, they retained their crystallinity and the amount of nickel incorporated could be tuned from 3.6 to 25 wt % according to the reaction conditions. The incorporation of a higher amount of nickel in NiCl@RIO‐12 consistently led to a lower Brunauer–Emmett–Teller surface area. Additionally, no agglomeration of nickel particles was found and a relatively homogeneous dispersion of nickel could be ascertained by SEM and TEM‐EDS. The paramagnetic material exhibited promising catalytic activity in Suzuki–Miyaura cross‐coupling under microwave heating. Thus, NiCl@RIO‐12 notably demonstrated good thermal stability and its recyclability showed no substantial loss of activity after 3 cycles.
Ni‐functionalized COF for heterogeneous catalysis: Nickel‐decorated COF materials NiCl@RIO‐12 were synthetized with tuneable amount of nickel incorporation from 3.6 to 25 wt %. The paramagnetic material exhibited promising catalytic activity in Suzuki–Miyaura cross‐coupling reactions under microwave heating. NiCl@RIO‐12 demonstrated good thermal stability and its recyclability showed no substantial loss of activity after 3 cycles.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Staufen1 (STAU1) is an RNA-binding protein involved in the post-transcriptional regulation of mRNAs. We report that a large fraction of STAU1 localizes to the mitotic spindle in colorectal cancer ...HCT116 cells and in non-transformed hTERT-RPE1 cells. Spindle-associated STAU1 partly co-localizes with ribosomes and active sites of translation. We mapped the molecular determinant required for STAU1-spindle association within the first 88 N-terminal amino acids, a domain that is not required for RNA binding. Interestingly, transcriptomic analysis of purified mitotic spindles revealed that 1054 mRNAs and the precursor ribosomal RNA (pre-rRNA), as well as the long non-coding RNAs and small nucleolar RNAs involved in ribonucleoprotein assembly and processing, are enriched on spindles compared with cell extracts. STAU1 knockout causes displacement of the pre-rRNA and of 154 mRNAs coding for proteins involved in actin cytoskeleton organization and cell growth, highlighting a role for STAU1 in mRNA trafficking to spindle. These data demonstrate that STAU1 controls the localization of subpopulations of RNAs during mitosis and suggests a novel role of STAU1 in pre-rRNA maintenance during mitosis, ribogenesis and/or nucleoli reassembly.
The fate of HKUST-1 (Cu
3
(BTC)
2
, BTC = 1,3,5-benzenetricarboxylate) in the green Deep Eutectic Solvent (DES) reline (choline chloride/urea 1 : 2) was investigated, highlighting that not only ...reline can be used to make this MOF but also to transform it into another crystalline material. The synthesis of HKUST-1(reline) showing good textural properties and a particular rose morphology was indeed successfully achieved in this solvent. However, upon optimizing the reaction conditions such as concentration and metal/ligand ratio, it was found that another structure Cu
2
(BTC)Cl also forms. It was unequivocally demonstrated that, upon heating in reline, HKUST-1 converts to the non-porous chloride-incorporating material. Hence, a novel feature of DES in MOF synthesis is uncovered: its role as a structure-directing agent, triggering the transformation between two different MOF structures.
The HKUST-1 MOF can not only be synthesized in the green deep eutectic solvent reline (choline chloride/urea 1 : 2) but also converts, upon heating in reline, to a 2D non-porous structure incorporating chloride anions.
For CaO‐based high‐temperature CO2 sorbents, excellent cyclic stability is highly desired for its practical applications. Among all techniques, preparation of CaO‐based composites is one of the most ...widely accepted strategies, and the mixing status between CaO and the inert supporting material is crucial for its anti‐sintering property. This work provides a new strategy for preparing nanometrically dispersed MgO/CaO composites with significantly improved cyclic stability. The so called solvent/nonsolvent synthesis method can endow a simultaneous solidification of Ca and Mg and result in a nano‐meter level mixing of CaO and MgO. The optimized sorbent Mg/Ca‐0.2 retained 95.3 % (13.45 mmol g−1) of its initial capacity after 7 cycles, while the control CaAc2−CaO only retained 52.9 % (8.67 mmol g−1) of its initial capacity. The addition of MgO also increase the CO2 sorption and desorption kinetics after several cycles. We believe that this new and facile solvent/nonsolvent synthesis method is also promising for the preparation of other highly mixed metal oxides.
Solvent/nonsolvent preparation of sintering‐resistant MgO/CaO composites. A new strategy for preparing nanometrically dispersed MgO/CaO composites with significantly improved cyclic stability was reported. The optimized sorbent Mg/Ca‐0.2 retained 95.3 % (13.45 mmol g−1) of its initial capacity after 7 cycles, while the control CaAc2−CaO only retained 52.9 % (8.67 mmol g−1) of its initial capacity.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We present X-ray properties of optically selected intermediate-mass (~105-106 M ) black holes (BHs) in active galactic nuclei (AGNs), using data from the Chandra X-Ray Observatory. Our observations ...are a continuation of a pilot study by Greene & Ho. Of the eight objects observed, five are detected with X-ray luminosities in the range L 0.5-2 keV = 1041-1043 erg s-1, consistent with the previously observed sample. Objects with enough counts to extract a spectrum are well fit by an absorbed power law. We continue to find a range of soft photon indices 1 < Gamma s < 2.7, where , consistent with previous AGN studies, but generally flatter than other narrow-line Seyfert 1 active nuclei (NLS1s). The soft photon index correlates strongly with X-ray luminosity and Eddington ratio, but does not depend on BH mass. There is no justification for the inclusion of any additional components, such as a soft excess, although this may be a function of the relative inefficiency of detecting counts above 2 keV in these relatively shallow observations. As a whole, the X-ray-to-optical spectral slope alpha ox is flatter than in more massive systems, even other NLS1s. Only X-ray-selected NLS1s with very high Eddington ratios share a similar alpha ox. This is suggestive of a physical change in the accretion structure at low masses and at very high accretion rates, possibly due to the onset of slim disks. Although the detailed physical explanation for the X-ray loudness of these intermediate-mass BHs is not certain, it is very striking that targets selected on the basis of optical properties should be so distinctly offset in their broader spectral energy distributions.