Magnetite can be synthesized from several different paths, for
example oxidation of Fe(OH)2 precipitate via green rust [13] or
through the reduction of hematite with hydrogen [14]. However, in
order to obtain nanoparticles, only specific methods have been
proven: iron complexes decomposition [15,16], mechanical alloying
[17], water/oil (w/o) microemulsion [18,19] and the Massart
method [20]. Some of the reported difficulties are the wide particle
size distribution and the large amount of solvent to spend [21]. The
last two methods above are the most frequently employed and
include Fe(II)/Fe(III) fast hydrolysis. In the original preparation
reported by Massart, an aqueous mixture of ferric and ferrous
chloride in hydrochloric acid is added to ammonia solution. The
gelatinous precipitate is then isolated from the solution by
centrifugation or magnetic decantation without washing with
water. The synthesis of magnetite nanoparticles by this way has
the advantages of operation simplicity, the use of economic
reagents and it is still useful to study the influence of solution
conditions in the size of the precipitated particles [22].
spherical but incipient octahedral crystals are observed. With
increasing iron concentration and temperature, an asymmetrical
distribution as well as dispersion in precipitated magnetite size
appeared. The magnetite obtained at 0.8 mol l1 and room
temperature, which has a similar diameter to the sample
synthesized at 0.4 mol l1 and 70 8C, represents an economical
variant of superparamagnetic nanoparticle synthesis because of its
high yield. Using the microtome cuts the spherical cellulose beads
reveal its internal structure containing large pores of about one
hundred nanometers as shown by TEM analysis. Magnetite
nanoparticles are confined within the pores that exist in the
cellulose structure. The magnetite nanoparticles maintain their
magnetic properties after the sphere flocculation.
Magnetite can be synthesized from several different paths, forexample oxidation of Fe(OH)2 precipitate via green rust [13] orthrough the reduction of hematite with hydrogen [14]. However, inorder to obtain nanoparticles, only specific methods have beenproven: iron complexes decomposition [15,16], mechanical alloying[17], water/oil (w/o) microemulsion [18,19] and the Massartmethod [20]. Some of the reported difficulties are the wide particlesize distribution and the large amount of solvent to spend [21]. Thelast two methods above are the most frequently employed andinclude Fe(II)/Fe(III) fast hydrolysis. In the original preparationreported by Massart, an aqueous mixture of ferric and ferrouschloride in hydrochloric acid is added to ammonia solution. Thegelatinous precipitate is then isolated from the solution bycentrifugation or magnetic decantation without washing withwater. The synthesis of magnetite nanoparticles by this way hasthe advantages of operation simplicity, the use of economicreagents and it is still useful to study the influence of solutionconditions in the size of the precipitated particles [22].spherical but incipient octahedral crystals are observed. Withincreasing iron concentration and temperature, an asymmetricaldistribution as well as dispersion in precipitated magnetite sizeappeared. The magnetite obtained at 0.8 mol l1 and roomtemperature, which has a similar diameter to the samplesynthesized at 0.4 mol l1 and 70 8C, represents an economical
variant of superparamagnetic nanoparticle synthesis because of its
high yield. Using the microtome cuts the spherical cellulose beads
reveal its internal structure containing large pores of about one
hundred nanometers as shown by TEM analysis. Magnetite
nanoparticles are confined within the pores that exist in the
cellulose structure. The magnetite nanoparticles maintain their
magnetic properties after the sphere flocculation.
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