Effect of zeta potential of particles dispersed in an aqueous solution on magnetic filtration efficiency

To use magnetic filtration technology for particle separation, it is necessary to clarify the extent to which electric and magnetic forces on particles compete with each other because particles are affected by both kinds of forces in aqueous solutions. We experimentally studied the effect of chemical conditions of the disperse phase on the electric forces acting on dispersed particles by doing magnetic filtration experiments under various chemical conditions. We applied zeta potential as an induction of electric force. The results revealed that as the zeta potential decreases the recovery of the suspensions increases. This was indicated from the fact that the repulsion force is small if the zeta potential is relatively low. Then, particles can approach each other without being repelled by electric charges during filtration, and this also causes the particles to grow to a size where they can be easily filtered from the solution. Separation between Eu₂O₃ and NiO was most effective at pH = 6.8, because the difference of the zeta potential between Eu₂O₃ and NiO was largest at this pH.