α-Fe2O3 samples
were manufactured
by means of the polymeric precursor method. The powders were sintered
and calcined at temperatures of 300–700 °C for 2 h, respectively.
In the X-ray diffraction results, the formation of the rhombohedral
phase without secondary phases was exhibited. The size of the particle
increased after calcination at 700 °C, exhibiting a slightly
more irregular morphology for the samples calcined with the addition
of NH4OH in the synthesis process. From the field-emission
scanning electron microscopy measurements, the particle size was determined,
showing a smaller size for the samples without NH4OH in
the synthesis process. The samples calcined at 600 °C had a size
of 100 nm, with the sizes for lower temperatures being smaller. The
size of the nanoparticle agglomerates was largest for the samples
with NH4OH; however, the zeta potential was slightly lower
over time for these samples. The phase study of the α-Fe2O3 nanoparticles was confirmed by means of Raman
spectroscopy, without additional bands of another crystal structure.
In addition, the synthesized nanoparticles exhibited good photocatalytic
activity in the degradation of rhodamine B (RhB) and atrazine (ATZ)
within 40 min, with a maximum degradation of 59% for ATZ and 40% for
rhodamine. The best responses in the degradation were for the samples
without the addition of NH4OH in the synthesis process
and in proportions lower than 0.1 g. The cytotoxic effects of the
nanoparticles obtained at 600 °C were evaluated in apical cells
of onion roots. The results are promising for future applications
because no changes were observed in the mitosis of the cells.