Bond-graph description and simulation of agitated bulk liquid membrane system—Dependence of fluxes on liquid membrane volume

The transport properties of an agitated bulk liquid membrane (ABLM) were studied experimentally and theoretically as dependent on its volume (V(m)). The solution-diffusion pertraction under stationary, quasi-stationary, and non-stationary conditions was described using the methods of the pseudo-thermodynamic network analysis (TNA). It was found that the fluxes in the system depend on the membrane volume to the degree conditioned by the kinetics of interfacial phenomena, diffusion coefficients, and equilibrium distribution coefficients. In general, for the systems operations in batch regime, the maximum output fluxes (stripping rates, Jmax) observed under non-stationary or pseudo-stationary conditions are lower than these observed for the stationary-state system and are represented by the following empirical polynomial:logJmax=∑i=0nai(logV(m))iThe results of calculations were experimentally verified by a pertraction study of bromothymol blue or benzoic acid in the ABLM system with a bulk liquid membrane made of octane. The proposed model and numerical procedures can be applied for the prediction of ABLM efficiency as dependent on the operational conditions and physico-chemical characteristics of the system or for fitting experimental data.

► The fluxes in the pertraction depend on the membrane volume.
► Non-stationary or pseudo-stationary stripping rates are lower than the stationary.
► Only the stationary flux is a unique quantity for describing transport properties.
► The results of calculations were experimentally verified.
► Volume effect can be described using log(flux) vs. log (membrane volume) polynomials.