The electrokinetic potential, also known as zeta potential, plays a crucial role in the stability of colloidal systems. Colloidal systems consist of dispersed particles solid, liquid, or gas in a continuous medium. The stability of these systems is determined by the forces acting between the dispersed particles, which can be attractive or repulsive.The mechanism behind the electrokinetic potential's effect on colloidal stability is based on the electrical double layer EDL that forms around the dispersed particles. When particles are dispersed in a liquid medium, they often acquire an electrical charge due to ionization, adsorption, or dissociation of surface groups. This charge attracts counterions from the surrounding medium, forming a layer of tightly bound ions called the Stern layer. Beyond the Stern layer, there is a diffuse layer of loosely bound counterions that extends into the bulk medium.The electrokinetic potential is the difference in electrical potential between the surface of the tightly bound Stern layer and the bulk medium. This potential influences the stability of colloidal systems in two ways:1. Repulsive forces: A high electrokinetic potential indicates a strong electrical charge on the particle surface. When two similarly charged particles approach each other, they experience a repulsive electrostatic force due to the overlapping of their electrical double layers. This repulsive force prevents the particles from aggregating, thus maintaining the stability of the colloidal system.2. Attractive forces: If the electrokinetic potential is low or the particles have opposite charges, the repulsive forces between the particles are weaker, and attractive forces such as van der Waals forces can dominate. In this case, the particles may aggregate, leading to the destabilization and eventual sedimentation or coagulation of the colloidal system.In summary, the electrokinetic potential affects the stability of colloidal systems by influencing the balance between repulsive and attractive forces between the dispersed particles. A high electrokinetic potential promotes repulsive forces and stabilizes the colloidal system, while a low electrokinetic potential allows attractive forces to dominate, leading to destabilization and aggregation of the particles.