Bio-mediated synthesis of monodisperse hematite nanoparticles from pyrite
Acidianus spp. a thermophilic bacteria which can oxidize sulphide minerals was used to oxidize pyrite, FeS2 resulting in the production of acidic ferric sulphate solutions. The ferric sulphate solutions were aged through a forced hydrolysis process at different pH conditions to yield a variety of...
| Main Author: | |
|---|---|
| Format: | Others |
| Language: | en |
| Published: |
2010
|
| Online Access: | http://hdl.handle.net/10539/8382 |
| Summary: | Acidianus spp. a thermophilic bacteria which can oxidize sulphide minerals was used
to oxidize pyrite, FeS2 resulting in the production of acidic ferric sulphate solutions.
The ferric sulphate solutions were aged through a forced hydrolysis process at
different pH conditions to yield a variety of iron oxide and basic sulphate precipitates.
The precipitates were characterized by XRD, SEM and BET analysis. Potassium
jarosite was formed as the main phase under acidic conditions whilst maghemite -
Fe2O3was precipitated as the main phase at a pH of 6-7. Magnetite Fe3O4 was formed
as the main phase at a pH of 7-8 as well as a pH of 8-9. Spherical globular
aggregates of magnetite nanoparticles of high purity and a surface area of 20.77m2/g
were precipitated at a pH of 7-8. Hematite -Fe2O3 nanoparticles were then produced
via an oxidative transformation of the precursor magnetite nanoparticles at 600°C.
The spherical hematite nanoparticles had a surface area of 18.69m2/g and a pore
volume of 0.0698cm3/g. This process can thus provide a cheaper alternative for the
production of hematite nanoparticles. Hematite nanoparticles have a wide range of
uses in fields such as electronics, optics and biomedicine. The findings can be used in
acid mine drainage treatment and other systems where iron removal is problematic. |
|---|