Stability of Monodispersed O/W Emulsion using SDS/Water/Kerosine System

Abstract

Effects of electrolytes (LiCl, NaCl, KCl, LiNO 3 , MgCl 2 , CaCl 2 , FeCl 3 and AlCl 3 ) on the stability of monodisperse O/W emulsion was investigated using an aqueous sodium dodecyl sulfate (SDS) solution/ kerosine system. The rate constants (k 2 ) for decrease in emulsion droplet number decreased with increase in the concentration of all electrolytes used and indicated a minimum value at a certain concentration of each electrolyte. A maximum zeta potential only for the emulsion droplet with a univalent cation electrolyte was obtained at the same concentration of electrolyte which gave minimum k 2 , but no correspondence was observed with various electrolyte concentrations of bi-and trivalent cations. The oil separation by centrifugation of the emulsion and interfacial tension of the aqueous SDS solution/kerosine system both decreased with increase in electrolyte concentration, It follows from the present results that increase in electrolyte concentration in bulk solution causes decrease in electrostatic repulsion and increase in the resistance of the membrane to coales, these cause k 2 to take on a minimum value