کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1489514 | 992308 | 2013 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Nano–micro-architectural composites with acid properties: Magnetic iron oxides/amorphous silicate prepared from iron oxide produced by iron-oxidizing bacterium, Leptothrix ochracea Nano–micro-architectural composites with acid properties: Magnetic iron oxides/amorphous silicate prepared from iron oxide produced by iron-oxidizing bacterium, Leptothrix ochracea](/preview/png/1489514.png)
To develop novel magnetic composites with acid functionalities, iron oxide produced by iron-oxidizing bacterium, Leptothrix ochracea, was used as a precursor. The composites were prepared by thermal treatment and subsequent reduction of the bacterial iron oxide. α-Fe2O3 nanoparticles obtained in air were thermally reduced to Fe3O4 and gradually oxidized to γ-Fe2O3. The obtained composites with Fe3O4 and γ-Fe2O3 have high magnetization values that are approximately half those of pure Fe3O4 and γ-Fe2O3. All samples have an interesting nano–micro-architectural structure: ∼40-nm-diameter crystalline particles covered with ∼8-nm-thick amorphous silicate are intricately interconnected into ∼1-μm-diameter microtubules. Pyridine adsorption spectra indicate that the surface amorphous silicate has both Brönsted and Lewis acid properties.
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► Iron oxides produced by bacteria are attractive sources of magnetic nanocomposites.
► Fe3O4 and γ-Fe2O3 nanoparticles covered with amorphous silicate were formed from iron oxide of bacterial origin.
► The amorphous silicate surface had a specific site with both Brönsted and Lewis acid properties.
Journal: Materials Research Bulletin - Volume 48, Issue 3, March 2013, Pages 1174–1177