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51.
A simple isotherm equation is derived for the adsorption of an organic component onto activated carbon in presence of water vapour. The theoretical results are compared with experimental data for toluene-water vapour-activated carbon, which were published byRipperger andGermerdonk [10].
Symbols a i adsorbate concentration in adsorbent, kg/kg of carbon - a 0i monolayer capacity, kg/kg of carbon - b i kinetic parameter of theLangmuir equation - E j adsorption energy in thej-th layer - i i-th component (1 — water vapour, 2 — organic compound) - j j-th layer - m number of layers - n number of adsorbed components - p partial pressure, Pa - p* saturation partial pressure, Pa - p C water vapour partial pressure at begining of capillary condensation, Pa - surface coverage 相似文献
Vorhersage der Adsorption einer organischen Komponente und Wasserdampf an Aktivkohle
Zusammenfassung Es wird eine einfache Adsorptionsisotherme abgeleitet, welche die gleichzeitige Adsorption eines organischen Stoffes und Wasser an Aktivkohle beschreibt. Die theoretischen Ergebnisse werden mit experimentellen Resultaten vonRipperger undGermerdonk [10] für Toluol-Wasser-Aktivkohle verglichen.
Symbols a i adsorbate concentration in adsorbent, kg/kg of carbon - a 0i monolayer capacity, kg/kg of carbon - b i kinetic parameter of theLangmuir equation - E j adsorption energy in thej-th layer - i i-th component (1 — water vapour, 2 — organic compound) - j j-th layer - m number of layers - n number of adsorbed components - p partial pressure, Pa - p* saturation partial pressure, Pa - p C water vapour partial pressure at begining of capillary condensation, Pa - surface coverage 相似文献
52.
Bogusław Bobrański 《Mikrochimica acta》1956,44(12):1735-1746
Zusammenfassung Das vom Verfasser undE. Sucharda schon 1928 angewandte Prinzip, die durch das Verhalten der Substanz beim Erhitzen bewirkten Druckschwankungen im Verbrennungsrohre zum Zwecke der automatischen Regulierung der Vergasungsgeschwindigkeit der Substanz bei der Elementaranalyse auszunutzen, wurde bei der Konstruktion einer neuen, elektrisch betriebenen, automatischen Apparatur angewandt. Hierbei wird das mit der Substanz gefüllte Mikroschiffchen mittels eines elektrischen Hochfrequenzgenerators erhitzt. Der Stromzufluß zu dem Hochfrequenzgenerator wird durch die erwähnten Druckschwankungen einoder ausgeschaltet. Die Verbrennung verläuft dann bei praktisch konstantem Druck im Verbrennungsrohre, also auch bei konstantem Sauerstoffüberschuß. Die neue Apparatur wird an Hand beigefügter Abbildungen beschrieben. Als Absorptionsmittel für Stickstoffoxyde werden 1 bis 2 g Bleidioxyd in einem 12 cm langen Porzellanschiffchen bei 190° angewandt. Die Absorption des Wassers erfolgt durch wasserfreies Kobaltchlorid, die der Kohlensäure ausschließlich durch Ascarit. Die Sauerstoffgeschwindigkeit im Verbrennungsrohre beträgt 8 ml pro Minute. Bei Substanzen, die mehr als 10% N enthalten, wird zwischen den Kohlensäureabsorptionsapparat und den Wasserabsorptionsapparat ein mit Mangandioxyd gefüllter Apparat eingeschaltet.
Summary The principle used by the author andE. Sucharda as early as 1928, which employs the variations in pressure in the combustion tube resulting from the behavior of the substance when heated, for automatically regulating the rate of gasifying the substance was applied in the construction of a new electrically operated automatic apparatus. The micro boat charged with the sample is heated by means of a high frequency generator. The flow of current to the high frequency generator is switched on and off by the variations in pressure mentioned above. The combustion then proceeds at practically constant pressure in the combustion tube, and even when there is a constant excess of oxygen. The new apparatus is described in the accompanying figures. The nitrogen oxides are absorbed in 1 to 2 grams of lead dioxide contained in a porcelain boat (12 cm long) at 190°. The absorption of the water is by means of anhydrous cobalt chloride, while the carbon dioxide is taken up in ascarite. The speed of the oxygen in the combustion tube is 8 ml per minute. In the case of samples that contain more than 10% nitrogen, an apparatus filled with manganese dioxide is placed between the carbon dioxide absorber and the apparatus for taking up the water.
Résumé Le principe de l'utilisation des variations de pression qui se produisent dans un tube à combustion en analyse élémentaire, lors du chauffage de la substance, a été utilisé dès 1928 par l'auteur etE. Sucharda pour la régulation automatique de la gazéification de cette substance. Il a été appliqué à la construction d'un nouvel appareil automatique commandé électriquement. La micronacelle qui contient la substance est chauffée électriquement à l'aide d'un générateur de courant de haute fréquence. Les variations de pression pendant la combustion provoquent l'ouverture ou la fermeture du circuit d'alimentation de ce générateur. Il en résulte que la combustion est effectuée à pression pratiquement constante ainsi qu'à excès d'oxygène constant. Ce nouvel appareil est décrit sur les figures de la publication.On utilise 1 à 2 grammes de bioxyde de plomb disposés dans une nacelle de porcelaine de 12 cm de longueur, portée à 190° pour absorber les oxydes de l'azote. L'eau est absorbée par du chlorure de cobalt anhydre et l'anhydride carbonique exclusivement par de l'ascarite. Le débit du courant d'oxygène dans le tube de combustion est de 8 ml par minute. Pour les substances contenant plus de 10% d'azote, on intercale un absorbeur à bioxyde de manganèse entre l'absorbeur à anhydride carbonique et l'absorbeur à eau.相似文献
53.
The enantiomers of some amino acids have been separated on commercial chiral TLC plates in reversed-phase mode. The effect
of the pH* of the aqueous-organic mobile phase on the retention and mobility of the enantiomers and on selectivity was investigated.
It was shown that for most of the amino acids investigated the highest enantioselectivity was obtained at pH* 3–4 or 6–7.
The drift and disturbance of the baseline on the chromatograms were also much smaller at pH* 3–4 and 6–7. 相似文献
54.
A grand canonical ensemble Monte Carlo simulation method is used to study the adsorption of nonadditive symmetric mixtures of Lennard-Jones spherical particles in nanoscopic slitlike pores. The walls of the pore are assumed to be formed by the parallel (100) planes of the model face centered cubic crystal of adjustable corrugation potential. It is demonstrated that depending on the nonadditivity effects in the mixture and the pore width the condensed phases formed inside the pore may have different structures. In particular, it is shown that the mixture may separate into layers containing only one component each and the stacking may depend on the pore width and properties of the mixture. 相似文献
55.
Tritium exchange at C-8 of xanthosine, theobromine, 1-, 3- and 7-methylxanthine in water has been studied. The rates of detritiation of these compounds have been determined over a pH range at constant temperature. Several mechanisms of exchange involving various ionic forms of substrate operating at different pH have been suggested. 相似文献
56.
W. Gołkiewicz 《Chromatographia》1986,21(5):259-264
Summary Equations describing multi-step gradient elution with a mobile phase of constant composition in each step were derived. These
equations useful for calculating the retention volumes in both gradient HPLC and TLC were derived on the basis of the relationship
between the isocratic capacity factor and the volume fraction of the organic modifier. The validity of the equations was experimentally
verified in a LiChrosorbRP-18-water/methanol system for 11 methyl- and chlorobenzenes and phenols. A satisfactory agreement
between the theoretical and experimental k′ values was found. 相似文献
57.
Summary The [Rh(acac){P(OPh)3)}2] complex (Hacac = 2,4-pentadione) reacts in solution with gaseous HCN in the presence of P(OPh)3 to give [Rh{P(OPh)3}3CN]. Structural investigations of this complex including its31P n.m.r. spectra are reported. 相似文献
58.
Berezkin Victor G. Mardanov Robert G. Moiseew Aleksey A. Malinowska Irena Różyło Jan K. 《平面色谱法杂志一现代薄层色谱法》2002,15(5):377-379
JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
59.
M. Czauderna J. Konecki M. Głowacka 《Journal of Radioanalytical and Nuclear Chemistry》1987,109(1):79-88
The incorporation of Se and Te into liver, kidneys, heart, spleen, lung and small intestine after i.p. injections of Balby mice with seleno-cystine (CySe)2 and Na2TeO3 in the presence of Cd (as CdCl2), As (as As2O3) and Zn (as ZnSO4) has been studied. The change of contents of Co, Fe, Rb and Hg were determined in all investigated organs after injections with the above compounds. Instrumental neutron activation analysis was applied as the analytical method. It was found that a competitive interaction occurs between As and Se or Te. Similarly, this interaction has been observed between Se and Cd. The data obtained suggest that Cd has a higher competitive ability to displace Te than Zn and Se. Injection with the above compounds affects the contents of Fe, Co, Rb and Hg in all mice organs. 相似文献
60.
Wiosetek-Reske AM Wysocki S Bak GW 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):1172-1178
The absorption and fluorescence spectra of N-nonyl acridine orange are determined at room temperature (298 K) in cyclohexane, benzene, carbon tetrachloride, chloroform, chlorobenzene and dichloromethane. The ground state of dipole moment was obtained by impedance measurements using Guggenheim-Debeye's method. The experimental excited state dipole moment of N-nonyl acridine orange was determined using Bakhshiev's and Kawski-Chamma-Viallet's formulae and solvent polarity parameter proposed by Reichardt. These experimental results were completed with theoretical results using quantum chemical methods. The experimental (muexp=10.76 D) and theoretical (mucal=9.9 D) dipole moments in the ground and excited state (muexp*=14.56 D) were compared. 相似文献