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001-es BibID:	BIBFORM102394
Első szerző:	Nagy Noémi, M. (vegyész, angol szakfordító)
Cím:	Study of the change in the properties of Mn-bentonite by aging / Noémi M. Nagy, Andrea Komlósi, József Kónya
Dátum:	2004
ISSN:	0021-9797
Megjegyzések:	In this paper the structure and properties of fresh manganese(II)?bentonite was compared with that of an old substance. It was concluded that the oxidation state of Mn changed. This did not cause many changes in the scanning electron microscope (SEM) and in the X-ray diffraction (XRD) studies; caused minor changes in the Mn concentration (determined by XRF) and thermoanalytical and electron spectroscopy analysis (ESCA). The change in the oxidation state of manganese was indicated by the colors of the samples, the difference in the surface sites, titration curves, redox potentials, adsorption, and catalytic activity of the fresh and the old Mn?bentonite. Potentiometric titration data were evaluated by a surface complexation model using the FITEQL3.2 computer program. Stability constants of edge charge reactions and the number of aluminol, silanol, and edge sites were calculated. Potentiometric titration data of commercial and freshly made MnO2 were also evaluated; the calculated constants and site numbers were compared with that of found in literature. Catalytic and adsorption activity of the samples were also investigated. It was found that fresh Mn?bentonite does not adsorb valine, while the old one and MnO2 does. Fresh Mn?bentonite does not catalyze the decomposition of H2O2, while the old one, as well as MnO2 does.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Manganese Oxidation state Bentonite Manganese dioxide Surface complexation model
Megjelenés:	Journal Of Colloid And Interface Science. - 278 : 1 (2004), p. 166-172. -
További szerzők:	Komlósi Andrea Kónya József (1937-) (vegyész)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM018703
Első szerző:	Nagy Noémi, M. (vegyész, angol szakfordító)
Cím:	Study of pH-dependent charges of soils by surface acid-base properties / Noémi M. Nagy, József Kónya
Dátum:	2007
ISSN:	0021-9797
Megjegyzések:	The pH-dependent charges of Hungarian soils have been studied via surface acid-base properties. The intrinsic stability constants of protonation and deprotonation processes, as well as the concentration of surface sites, have been determined by surface complexation modeling. The protonation and deprotonation constants have been nearly the same for most soils. There is a relation between the concentration of surface sites and composition, expect for the freshly deposited soils with high primary silicate content. The results show that the concentrations of silanol and aluminol sites are different for each soil, the intrinsic stability constants of protonation and deprotonation processes, however, are nearly the same within experimental error. This can only be explained if these stability constants are real thermodynamic equilibrium constants. The fact that these constants are nearly the same supports the conclusion that we succeeded in excluding all processes that would disturb the measurements. The parameters characteristic of the edge sites of the soils are of two types: (a) the parameters depending on the quality and composition of the soils, (i.e.), the concentration of surface sites; (b) the parameters depending on the thermodynamically well-defined acid-base processes, independent of soil composition. (c) 2006 Elsevier Inc. All rights reserved.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban soil pH-dependent charge
Megjelenés:	Journal Of Colloid And Interface Science. - 305 : 1 (2007), p. 94-100. -
További szerzők:	Kónya József (1937-) (vegyész)
Pályázati támogatás:	Bolyai Ösztöndíj Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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