In this paper

monolayer saturation and nonideal surfactant interactions are captured with a nonlinear adsorption framework.The migration of a droplet in surfactant solution with electrolyte is discussed.Most prior research studied the migration of a bubble or a droplet in surfactant solution without electrolyte.When the surfactants in solution with electrolyte are adsorbed at the surface of a bubble or a droplet

an electrical double layer will form near the surface of the bubble or the droplet

which will affect the subsequent adsorption of the surfactants.A group of dimensionless parameters(the interaction coefficient of the adsorbed surfactants K ∞

the Marangoni number Ma

the Biot number Bi and the viscosity ratio k )are discussed in detail.The surface concentration of the adsorbed surfactants

the surface velocity and the migration velocity of the droplet are obtained by a boundary collocation technique.The terminal velocity U 0 of the droplet increases as K ∞ increases.