Removal of fluoride ions using a polypyrrole magnetic nanocomposite influenced by a rotating magnetic field.

The impact of a varying rotating magnetic field in stimulating adsorption of fluoride ions onto a polypyrrole magnetic nanocomposite synthesized via in situ a polymerization process was evaluated. Under the effect of a rotating magnetic field, improved removal of adsorbate (10 mg L -1 ) from aqueous solution using the polypyrrole magnetic nanocomposite was observed, with a maximum removal of 78.2% observed at a magnetic field intensity of 0.019 T. Particle aggregation resulting from the force owing to the gradient on the particles as the magnetic field was increased resulted in improved fluoride removal. This aggregation of particles leads to an improved chain collision and expanse of particle interaction with the fluoride solution. The process of adsorption of fluoride by the PPy/Fe 3 O 4 nanocomposite followed both the Freudlich isotherm and the Temkin isotherm. Interestingly, under the effect of the rotating magnetic field, the adsorption process was best described by the Freundlich isotherm.