Síntesis de nanopartículas de hematita por el método de precipitación controlada

Content Provider	Semantic Scholar
Author	Berrones, María De Los Ángeles Lascano, Luís Lascano
Copyright Year	2009
Abstract	In this study it was synthesized and characterized nano-sized iron oxides (III) by the controlled precipitation method (CPM). The processing has three stages: precipitation of precursors, washing and calcination. First, it was performed a potentiometric titration, and it was constructed a voltage curve as a function of pH in order to obtain the equivalence point of the same. With these variables the precipitation was controlled with ferric chloride as precursor, and sodium hydroxide as precipitant, in constant agitation and pH 6. It tested different reaction times: 1, 3 and 5 hours, and after 1 hour of reaction it was concluded that it is possible to obtain hematite, but after 5 hours it can be obtained much hematite. The products obtained from the reaction were washed by centrifugation, dried at 60 C, and were calcined at temperatures of 350, 400, 450 and 500 C, for two hours. To characterize the product obtained in the synthesis, it has been used XDR, FT-IR, SEM, EDS techniques, and in order to determine the particle size distribution it has been used light scattering. Washed samples with five hours of reaction without calcination and calcined at 350 C are associated to ferrihydrite, while if it is calcinated at 400 C gives a mixture of hematite and ferrihydrite, but at 450 C and 500 C, it is achieved hematite with nearly-spherical shape with 2% of traces of sodium chloride like impurities persistent even after the washing process. Finally, it has been found nanoparticles up to 74 nm by dispersing the sample in water at pH 12, with 25 minutes of sonication and 96 hours of settling time.
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Alternate Webpage(s)	http://bibdigital.epn.edu.ec/bitstream/15000/5547/1/Mar%C3%ADa-de-los-%C3%81ngeles-Berrones.pdf
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article