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An advanced cation-exchange nano-composite poly- o-toluidine Ce(IV) phosphate was synthesized by sol-gel technique by incorporating Ce(IV) phosphate precipitate with the matrix of poly- o-toluidine. The material showed good ion-exchange behavior and used successfully in separation of metal ions. The conductivity of the composite was found within the range of 10 to 10S/cm; measured by four-in-line probe DC electrical conductivity measuring technique. The conductivity is at the border of metallic and semiconductor region. Ion-exchange kinetics for few divalent metal ions was evaluated by particle diffusion-controlled ion-exchange phenomenon at four different temperatures. The particle diffusion mechanism is confirmed by the linear τ (dimensionless time parameter) versus t (time) plots. The exchange processes thus controlled by the diffusion within the exchanger particle for the systems studies herein. Some physical parameters like self-diffusion coefficient ( D), energy of activation ( E), and entropy of activation (∆ S°) have been evaluated under conditions favoring a particle diffusion-controlled mechanism. [ABSTRACT FROM AUTHOR]