resumo
Magnetic spinel ferrite particles were successfully prepared from only iron (III) nitrate, using clove and cinnamon plant extracts for the first time as eco-fuels for auto-ignition synthesis. Both natural substances were shown to play dual roles in the synthesis of the magnetic particles; i.e. as fuels (agents for biogenic reduction), and as anti-oxidants for preserving the magnetic phases during subsequent heating. In this regard, no special protective environments such as H-2/N-2 or argon gases were required during the heat stabilisation process, and samples could be stabilised by heating to 550 degrees C in air. The magnetic crystalline phase is mostly maghemite (gamma-Fe2O3) rather than magnetite (Fe3O4), as revealed by Raman, since no Raman active phonon modes were detected for magnetite, and most of the bands were related to maghemite, with traces of hematite. Both fuels produced strongly magnetic soft ferrites, with magnetisation values of 75 A m(2) kg(-1), around the expected ones for maghemite Moreover, TG curves showed that maghemite degradation only occurs at relatively high temperatures, namely at 550 degrees C for Clove, and at 744 degrees C for Cinnamon, confirming the sustainable nature of the as-obtained materials against oxidation. (C) 2019 Elsevier B.V. All rights reserved.
palavras-chave
ALOE-VERA; SILVER NANOPARTICLES; RAMAN-SPECTROSCOPY; GREEN SYNTHESIS; ESSENTIAL OIL; BIOSYNTHESIS; TEMPERATURE; AROMATICUM; MAGHEMITE; EXTRACTS
categoria
Chemistry; Materials Science; Metallurgy & Metallurgical Engineering
autores
Bena-Arfa, BAE; Salvado, IMM; Ferreira, JMF; Pullar, RC
nossos autores
Basam Abobaker Emhmed Ben-Arfa
Investigador
Isabel Margarida Miranda Salvado
Professor associado
José Maria da Fonte Ferreira
Professor(a) Jubilado(a)
Rob Pullar
ColaboradorGrupos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
Projectos
agradecimentos
R.C. Pullar wishes to thank the FCT Grant IF/00681/2015 for supporting this work. B.A.E. Ben-Arfa thanks FCT grant BIONANOSCULP PTDC/EPH-PAT/6281/2014 for supporting him during this work. This work was developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. We thank Dr Joao Amaral for the magnetic measurements.