Adsorption of CO2 on nitrogen-enriched activated carbon and zeolite 13X

Adsorption may be a potentially attractive alternative to capturing CO₂ from stationary sources in the context of Carbon Capture and Sequestration (CCS) technologies. Activated carbon and zeolites are state-of-art adsorbents which may be used for CO₂ adsorption, however physisorption alone tends to be insignificant at high temperatures. In the present work, commercial adsorbents have been impregnated with monoethanolamine (MEA) and triethanolamine (TEA) in order to investigate the effect of the modified surface chemistry on CO₂ adsorption, especially above room temperature. Adsorption isotherms for CO₂, N₂ and CH₄ were measured in a gravimetrically system in the pressure range of UHV to 10 bar, at 298 and 348 K for activated carbon and zeolite 13X supports. The adsorbed concentration of CO₂ was significantly higher than those of CH₄ and N₂ for both adsorbents in the whole pressure range studied, zeolite 13X showing a remarkable affinity for CO₂ at very low pressures. However, at 348 K, the adsorbed concentration of CO₂ decreases significantly. The supports impregnated with concentrated amine solutions and dried in air suffered a detrimental effect on the textural properties, although CO₂ uptake became much less susceptible to temperature increase. Impregnations carried out with dilute solution followed by drying in inert atmosphere yielded materials with very similar textural characteristics as compared to the parent support. CO₂ isotherms in such materials showed a significant change with similar capacities at 348 K as compared to the original support at 298 K in the case of activated carbons. The impregnated zeolite showed a decrease in adsorbed phase concentration in low pressures for a given temperature, but the adsorbed amount also seemed to be less affected by temperature. These results are promising and indicate that CO₂ adsorption may be enhanced despite high process temperatures (e.g. 348 K), if convenient impregnation and drying methods are applied.     

Interaction Between Plumbagin and Human Serum Albumin by Fluorescence Spectroscopy

The interaction of plumbagin (PLU) with human serum albumin (HSA) in physiological buffer (pH=7.4) was studied by fluorescence spectroscopy. Results obtained from analysis of the fluorescence spectra indicated that PLU has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. Fluorescence quenching data revealed that the quenching constants (K) are 4.43×10⁴, 3.26×10⁴ and 1.69×10⁴ L?mol^?1 at 293, 303 and 313 K, respectively. The thermodynamic parameters ΔH° and ΔS° were calculated to be ?36.63 kJ?mol^?1, and ?35.702 J?mol^?1?K^?1 respectively, which suggested that van der Waals interactions and hydrogen bonds play a major role in the interaction of PLU with HSA. The distance between donor (HSA) and acceptor (PLU) was calculated to be 3.76 nm based on Förster’s non-radiative energy transfer theory. The results of synchronous fluorescence spectra showed that binding of PLU to HSA can induce conformational changes in HSA.     

Surface modification of titanium by using plasma‐induced graft‐polymerization

Plasma‐induced graft‐polymerization (PIGP) method was utilized in this study to improve corrosion behavior and biocompatibility of titanium (Ti) surface. Bioactive molecule polyacrylamide (PAM) was immobilized onto Ti surface by introducing silanederivatized spacer arms as an intermediary for the covalent linkage. Ti was firstly activated by O₂ plasma, and oxygen‐containing groups were introduced on its surface consequently. The intermediary mercapto silane spacer molecules were then covalently linked to the oxidated surface, followed by the covalent binding of PAM and the sulfhydryl‐terminal groups via PIGP. Surface analyses following modification process included water contact angles (CA), SEM, attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR), XPS and atomic force microscope (AFM). The results revealed the effectiveness of this method on immobilizing PAM to Ti surface, and the hydrophilicity of modified surface improved remarkably. In addition, potentiodynamic polarization and cellular proliferation tests were implemented to validate the enhanced corrosion‐resistance and biocompatibility of modified Ti surface, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

1H NMR and UV-visible data fusion for determining Sudan dyes in culinary spices

Two data fusion strategies (variable and decision level) combined with a multivariate classification approach (Partial Least Squares-Discriminant Analysis, PLS-DA) have been applied to get benefits from the synergistic effect of the information obtained from two spectroscopic techniques: UV-visible and ¹H NMR. Variable level data fusion consists of merging the spectra obtained from each spectroscopic technique in what is called “meta-spectrum” and then applying the classification technique. Decision level data fusion combines the results of individually applying the classification technique in each spectroscopic technique. Among the possible ways of combinations, we have used the fuzzy aggregation connective operators. This procedure has been applied to determine banned dyes (Sudan III and IV) in culinary spices. The results show that data fusion is an effective strategy since the classification results are better than the individual ones: between 80 and 100% for the individual techniques and between 97 and 100% with the two fusion strategies.     

Selective synthesis of 2-substituted 4-carboxy oxazoles, thiazoles and thiazolidines from serine or cysteine amino acids

The synthesis of new 4-carboxy oxazoles, thiazoles and thiazolidines by condensation of serine or cysteine with aldehydes or acids is described. Due to the optimization of a mild and selective procedure, which takes advantage of the positive effect of microwave irradiation on the MnO₂ mediated oxidation step, the 2-substituted-4-carboxy derivatives can be obtained in multi-gram scale. Examples of coordination chemistry to Ni(II) and Co(II) are described.     

NiMo 催化剂上MoS2 形貌与其DBT 加氢脱硫选择性的关系

制备了两个系列不同镍钼负载量的NiMo 催化剂,并用X 衍射、N2 物理吸附和透射电镜进行了表征。以二苯并噻吩
为模型硫化物,在高压固定床微型反应器上对该NiMo 催化剂的加氢脱硫性能进行了评价,研究了MoS2 形貌与催化剂加氢脱
硫选择性之间的关系。结果表明,镍钼负载量对MoS2 形貌有明显的影响。Mo18Ni4 催化剂(含18% MoO3 和4% NiO)上
MoS2 呈多级层状结构,具有较高的加氢脱硫活性和优异的加氢脱硫选择性。加氢选择性与催化剂上活性组分MoS2 的堆积层
数相关联呈很好的线性关系;堆积层数越多,其加氢选择性也越高。     

多金属ZSM-5催化剂的制备及其催化氨化合成2,6-二甲基吡啶

通过掺杂制备了一系列多金属改性的ZSM-5催化剂,并用于丙酮和甲醇氨化合成2,6-二甲基吡啶的反应中.在固定床反应器上筛选出催化性能良好的催化剂6%Pb-0.5%Fe-0.5%Co/ZSM-5(200),探讨了过渡金属掺杂的促进作用,并考察了反应温度、氨醇比、酮醇比、水含量和停留时间对反应性能的影响.结果表明,该催化剂...     

Molecular cloning and transgenic expression of a synthetic human erythropoietin gene in tobacco

Erythropoietin (EPO) is a hormone belonging to a group of hematopoietic growth factors that control the proliferation and differentiation of bone marrow cells. It induces the production of erythrocytes, thereby increasing the amount of circulating hemoglobin and oxygen. Previous attempts to transgenically express human EPO in plants failed to succeed because the plants exhibited abnormal morphology and infertility. In the present work, we describe the generation of fertile transgenic tobacco plants able to express a synthetic version of human EPO. A 582-bp fragment of the human EPO gene was synthesized using a PCR-based method and ligated into pCR-Blunt. After sequencing, the human EPO fragment was transferred to pWUbi.tm1 and the expression cassette was then transferred to the binary vector pWBVec4a. After Agrobacterium-mediated transformation of Nicotiana tabacum SR1 plants, integration of the transgene into T₀ and T₁ plant genomes was confirmed by PCR. The human EPO gene was found to be expressed in tobacco leaves at the mRNA and protein levels. Self-crossing allowed us to obtain T₁ plants exhibiting Mendelian segregation of the transgene. None of the plants presented any kind of malformation or deformity.     

Supramolecular engineering through temperature-induced chemical modification of 2H-tetraphenylporphyrin on Ag(111): flat phenyl conformation and possible dehydrogenation reactions

Scratching the surface: Formation of a monolayer of 2H-tetraphenylporphyrins (2H-TPP) on Ag(111), either by sublimation of a multilayer in the range 525-600?K or by annealing (at the same temperature) a monolayer deposited at room temperature, induces a chemical modification of the molecules. Rotation of the phenyl rings into a flat conformation is observed and tentatively explained, by using DFT calculations, as a peculiar reaction due to molecular dehydrogenation.