In order to precipitate the cellulose beads, three sizes of
synthetic magnetite, ranging from 6.5 to 12.5 nmin diameter, were
used. The composite was obtained by dispersing 0.18 g of Fe3O4
nanoparticles in water, followed by mixing the previous suspension
in 50 g of viscose (9%, w/w of cellulose in the viscose) during
5 min. The mixture was then dispersed in 124 ml of kerosene and
9 ml of oleic acid, maintaining the stirring 10 min at 1700 rpm and
room temperature, then was heated to 88–90 8C. The product was
filtered and washed with hot water to regenerate the cellulose;
finally it was washed in situ with ethanol, acetone and cold water.
The concentration of magnetite in cellulose beads was 4% (w/w).