A plasticized cellulose triacetate (CTA) membrane consisting of N-6-(t-dodecylamido)-2-pyridine carboxylic acid (t-DAPA) as a new carrier to facilitate membrane transport of copper(II) has been prepared to develop the selective recovery system for copper(II) from other divalent metal ions. First of all, the solid (CTA)-liquid extraction equilibrium of copper(II) was examined to obtain information concerning Cu(II)-t-DAPA complex stoichiometry and its extraction constant in the CTA membrane. Membrane transport studies were performed in a two-compartment cell. The CTA-t-DAPA membrane exhibited uphill transport of copper(II) against the concentration gradient. The influences of the aqueous and membrane components on the permeability of copper(II) were studied to elucidate its transport mechanism. Their results suggest that the transport mechanism consists of a diffusion process through an aqueous diffusion film, a fast interfacial chemical reaction, and diffusion through the membrane itself. The mass-transfer coefficients in the aqueous film phase (k(a)) and membrane phase (k(m)) were determined based on the diffusion model, using the stoichiometric relationship of the extracted species of copper(II) and the extraction equilibrium constant (K-ex), determined independently by solid-liquid extraction. Their mass-transfer coefficients obtained were k(a) = 7.8 x 10(-6) m/s and k(m) = 2.0 x 10(-9) m/s.