Electroflocculation: the effect of zeta-potential on particle size

Electroflocculation (EF) of wastewater or water for reuse with colloidal particles, such as kaolin and iron with the right pH, might be optimal for aggregation during water treatment. In this paper, the EF process was compared to chemical flocculation (CF) through ζ-potential and particle size parameters. The results demonstrate that the particle became larger, except in the case of pH 4, where, after 50 min of flocculation, there was a jump in the value and the particle attained a diameter of more than 800 nm. Throughout the entire flocculation time, the ζ-potential values indicated a stronger negative charge on the particle. Basically, there was a gradual rise in absolute ζ-potential with the increase in particle size. The reason for this behavior can be explained by the solubility of kaolin with a decreasing ionic strength, when certain iron ions are released from the electrode and the charge of the particle is altered. The aggregation process, whereby a few small particles with a negatively-charged surface are rendered into a larger-sized particle, results in a larger total negative charge. It has long been recognized that ζ-potential is a very good index of the magnitude of the repulsive interaction between colloidal particles. Measurements of ζ-potential are commonly used to assess the stability of colloidal and particle size produced by EF. Thus, the coupling of the EF of kaolin and iron with the right pH might be optimal for producing particles.