Search results for "DSO"
showing 10 items of 1609 documents
Fine chemistry by TiO2 heterogeneous photocatalysis
2021
Abstract Heterogeneous TiO2 photocatalysis is a promising technology based on the capability of the semiconducting material to generate charges upon irradiation of suitable energy. The photogenerated electrons and holes, in turn, induce redox reactions involving species adsorbed on the surface of the photocatalyst, giving rise to chemical transformations. The presence of highly oxidizing radicals, thus generated, has long led to consider TiO2 photocatalysis only a nonselective oxidation process. In fact, so far it is possible to find in the literature many examples of its use in the field of environmental remediation aimed at the degradation of harmful molecules, although the studies are al…
The Role of the Energetics of Adsorption in Kinetic Studies
1981
Adsorptionsvoltammetrische Bestimmung von Titan
1986
Investigation on the Adsorption of N2 Ar, CO and CH4 on Aluminophosphates
1994
Abstract Adsorption isotherms at different temperatures and isothermal micro-calorimetric curves were measured for N2 Ar, CO, and CH4 on various molecular sieves as VPI-5, MCM-9, AlPO4-8, AlPO4-H, AlPO4-5, SAPO-5, AlPO4-39, AlPO4-C. It was shown that the isosteric heats of adsorption correlated with the pore-sizes of the studied molecular sieves.
Adsorptionseffekte als Fehlerquellen bei Lichtzerstreuungsmessungen
1956
Es werden die Einflusse der Adsorption von Hochpolymeren aus den Losungen auf Lichtzerstreuungsmessungen untersucht. Zunachst wird die Adsorption aus Losung an Glaswolle und Glaspulver in verschiedenen Losungsmitteln gemessen. Es zeigt sich, das sowohl Konzentrationserniedrigung, bestimmt im Differentialrefraktometer, wie auch eine Abnahme des Molekulargewichtes, aus der Lichtzerstreuung bestimmt, infolge selektiver Adsorption auftreten. Beim Schutteln der Losungen tritt als weiterer Effekt ein Abbau der Kettenmolekule ein. Beim Filtrieren von Losungen nehmen durch Adsorption im Filter Konzentration und Molekulargewicht ab. Die Abnahme wachst mit der Feinheit des Filters, d. h. mit seiner O…
Adsorption Properties of Nax and Bax Zeolites: Correlation between Structural and Thermodynamic Results on Para- and Meta-xylene Adsorption
1996
A comparison is made between NaX and BaX adsorption properties starting from crystallographic data and thermodynamic measurements. Adsorption isotherms and differential adsorption heats of pure para- and meta-xylenes in NaX and BaX zeolites are interpreted in the light of crystallographic results.
Retention of Vanadium(V), Molybdenum(VI) and Tungsten(VI) by Kaolin
1993
Abstract The ability of kaolin (approximately H2Al2Si2O8 · H2O), a well known clay mineral constituent, to retain V(V) andMo(VI) species from 10−5 and 10−4 M solutions, and W(VI) species from 10−4 M solutions was investigated in the pH range 2–7.5 using a solid/liquid ratio 1:100 (w:v). The equilibration time in the adsorption studies was 72 h, and the shaking time in the desorption studies was 17 h. 0.02 M KCl was used as ionic medium and desorbing liquid. V(V), Mo(VI) and W(VI) were all retained by kaolin to some extent, and the amounts of the elements which could be washed away from kaolin with 0.02 M KCl were very small. The pH dependence of the adsorption was considerable: when added a…
Characterization of NOM
2015
Worldwide reports over the last few decades have shown that the amount of natural organic matter (NOM) in surface water is continuously increasing, which has an adverse effect on drinking water purification. For many practical and hygienic reasons, the presence of NOM in drinking water is undesirable. Various technologies have been proposed for NOM removal with varying degrees of success. The properties and amount of NOM, however, can significantly affect the process efficiency. To improve and optimize these processes, it is essential to characterize and quantify NOM at various points during purification and treatment. It is also important to be able to understand and predict the reactivity…
Confined But-2-ene catalytic isomerization inside H-ZSM-5 models: A DFT study
2015
The isomerization of cis-but-2-ene to trans-but-2-ene within a 22T H-ZSM-5 zeolite model, also in the presence of two adsorbed Pd atoms, has been studied by DFT calculations. The results obtained allow us to state that the cis/trans but-2-ene isomerization can easily proceed inside unsupported zeolite cavities. In this case, differently than in the gas phase reaction, the trans-but-2-ene is less stable than the cis-but-2-ene, when adsorbed on the zeolite inner surface. Excluding the adsorption-desorption steps, the isomerization process involves two intermediates and three transition states, whose energy content is always very low with respect to that of reagents and intermediate species. T…