Phosphates in high concentrations are harmful pollutants for the environment, and new
and cheap solutions are currently needed for phosphate removal from polluted liquid media. Iron
oxide nanoparticles show a promising capacity for removing phosphates from polluted media and
can be easily separated from polluted media under an external magnetic field. However, they have to
display a high surface area allowing high removal pollutant capacity while preserving their magnetic
properties. In that context, the reproducible synthesis of magnetic iron oxide raspberry-shaped
nanostructures (RSNs) by a modified polyol solvothermal method has been optimized, and the con-
ditions to dope the latter with cobalt, zinc, and aluminum to improve the phosphate adsorption have
been determined. These RSNs consist of oriented aggregates of iron oxide nanocrystals, providing a
very high saturation magnetization and a superparamagnetic behavior that favor colloidal stability.
Finally, the adsorption of phosphates as a function of pH, time, and phosphate concentration has
been studied. The undoped and especially aluminum-doped RSNs were demonstrated to be very
effective phosphate adsorbents, and they can be extracted from the media by applying a magnet.Instituto de Física (IF
