“…where σ is the thickness of the hollow fibre, τ is the membrane totuosity, ε is the membrane porosity and D m is the molecular diffusivity of the carrier-solute complex Other equations have also been used by researchers in this field (de Haan, et al, 1989;Hu and Wiencek, 1998). For the organic phase flowing through the shell side of the contactor, the value of (k o ) can be estimated using the following equation (Yang and Cussler, 1986): It is concluded that the estimation by any empirical correlation mentioned in the literature require a description of the specific system, the characteristics of the fibres and contactor, the physical and transport properties of the system under study, the operating conditions and the assumption that the specific system is at least similar to the one where the correlation was developed.…”