Robić, Marko; Ristić, Mira; Krehula, Stjepko; Musić, Svetozar Effects of Cr3+ ions and hexamethylenetetramine on the forced hydrolysis of FeCl3 solutions. In: Mössbauer Spectroscopy from Magnetic Nanoarchitectures to Environmental Science: A Symposium in Honor of Dr. Jean Marc Greneche, American Chemical Society (ACS Fall 2021) (22 August 2021 - 26 August 2021) Atlanta & online.
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Abstract
The structural analysis and nano/microstructural properties of the precipitates formed by forcedhydrolysis at 160°C of FeCl3 solutions in the presence of Cr ions and HMTA (hexamethylenetetramine) were investigated. Phase compositions were determined by combining X- ray diffraction, Fe Mössbauer and FT-IR spectroscopy, whereas nano/microstructural properties were analyzed with scanning electron microscopy (FE SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The phase analyses of the precipitates showed the presence of 2-XRD lines ferrihydrite (amorphous- like), α-FeOOH, β- FeOOH, and α-Fe2O3, and the exact phase composition was strongly dependent on the starting chemical composition in the solution and the precipitation time. 2-XRD lines ferrihydrite, α- FeOOH and β-FeOOH were the precursors of the α- Fe2O3 as end-product. Upon 2 h of autoclaving at 160°C, the precipitates consisted of nanoparticles in size ~35 to ~50nm and after 24 h their size increased to ~100 nm. New shapes of these nanoparticles were found. The formation of solid solutions between Cr ions and iron oxides cannot be excluded taking into account the decreased values of hyperfine magnetic field (HMF) relative to reference samples as well as EDS. Uponautoclaving of the precipitation system 0.01 M FeCl3+0.01 M CrCl3 + 0.25 M HMTA up to 6 h the 2- XRD lines ferrihydrite was obtained, whereas after 24 h the cracking of amorphous-like matrix (2-XRD lines ferrihydrite)occurred and in the cracking area the formation of dendritic nano/microstructures appeared.
| Item Type: | Unpublished conference/workshop items or lecture materials | ||||||||
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| Uncontrolled Keywords: | hematite ; forced hydrolysis | ||||||||
| Subjects: | NATURAL SCIENCES > Chemistry > Inorganic Chemistry NATURAL SCIENCES > Chemistry > Applied Chemistry |
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| Divisions: | Division of Materials Chemistry | ||||||||
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| Depositing User: | Marko Robić | ||||||||
| Date Deposited: | 16 Dec 2025 10:28 | ||||||||
| URI: | http://fulir.irb.hr/id/eprint/10491 |
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