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001-es BibID:	BIBFORM082255
Első szerző:	Lázár István (vegyész)
Cím:	Iron oxyhydroxide aerogels and xerogels by controlled hydrolysis of FeCl3.6H2O in organic solvents : stages of formation / I. Lázár, A. Szilágyi, G. Sáfrán, Á. Szegedi, S. Stichleutner, K. Lázár
Dátum:	2015
ISSN:	2046-2069 2046-2069
Megjegyzések:	Iron oxyhydroxide aerogels and xerogels were prepared by controlled hydrolysis of FeCl3.6H2O in organic solvents by using a limited amount of water or consuming solely water molecules available from the crystals. Ethanol, ethylene glycol, dimethyl sulfoxide (DMSO) and dimethyl formamide (DMFA) solvents were used, the hydrolysis was promoted with epichlorohydrin proton scavanger. High surface area aerogels were prepared by supercritical CO2 extraction of solvents, surface area and pore distribution measurements were performed on them. Aerogel and xerogel samples were characterized by XRD, Mössbauer spectroscopy and HRTEM methods. The process of hydrolysis was followed by recording Mössbauer spectra of frozen reaction mixtures. Stepwise progress and appearance of transient components were detected in DMSO and DMFA solvents. Aerogel samples exhibit asymmetric spectra with low probability of Mössbauer effect in their as synthesized state. In contrast, frozen reaction mixtures, gels, dry xerogels and compressed aerogels display symmetric spectra with high probability of the Mössbauer resonance. XRD proves the dominant presence of 2-line ferrihydrite. HRTEM studies reveal 4-8 nm typical particle sizes with 0.21-1.0 nm characteristic lattice distances. Different types of coordination environments are distinguished for iron in the formed ferrihydrite nanoparticles due to structural features and imperfections.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	RSC Advances. - 5 : 89 (2015), p. 72716-72727. -
További szerzők:	Szilágyi A. Sáfrán György Szegedi Ágnes Stichleutner Sándor Lázár Károly
Pályázati támogatás:	TÁMOP-4.2.2.A-11/1/KONV-2012-0036 TÁMOP
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM081490
Első szerző:	Lázár Károly
Cím:	Iron Oxyhydroxide Aerogels and Xerogels by Hydrolysis of FeCl3 ? 6 H2O in Organic Media : early stages / Károly Lázár, István Lázár, György Sáfrán, Anett Szilágyi
Dátum:	2015
ISSN:	0011-1643
Megjegyzések:	Formation of iron oxyhydroxide aerogel and xerogel by hydrolysis of FeCl3 ? 6 H2O was studied in organic media using water available solely from the starting iron salt. Ethylene glycol (EGLY), dimethyl sulfoxide (DMSO) and dimethyl formamide (DMFA) solvents were used. Products were analysed with specific surface area and TEM measurements. Early stages of hydrolysis and progress of gelation were followed by Mössbauer spectroscopy of frozen reaction mixtures. Presence of transient species and increase of the probability of the Mössbauer effect was observed in the early phase (0-60 min). Hydrolysis and gelation were the faster in EGLY, proceeded with medium rate in DMSO and were the slowest in DMFA.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk iron hydrolysis transient components organic solvents recoilless fraction Mössbauer spectroscopy
Megjelenés:	Croatica Chemica Acta. - 88 : 4 (2015), p. 413-419. -
További szerzők:	Lázár István (1959-) (vegyész) Sáfrán György Szilágyi Anett
Pályázati támogatás:	TÁMOP-4.2.2.A-11/1/KONV-2012-0036 TÁMOP
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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