XXV ARS SEPARATORIA – Toru, Poland 2010 260 BOND-GRAPH DESCRIPTION AND SIMULATION OF MEMBRANE PROCESSES: HYBRID PERTRACTION IN MULTIMEMBRANE SYSTEM Grayna SZCZEPASKA, Piotr SZCZEPASKI, Romuald WÓDZKI Nicolaus Copernicus University, Faculty of Chemistry, 87-100 Toru, Gagarina 7, Poland Abstract Thermodynamic network analysis (TNA) was applied for modeling and theoretical description of the hybrid pertraction of univalent cations in the multimembrane hybrid system (MHS). Some numerical calculations were carried out to describe the evolution of the transport systems as dependent on the initial conditions for pH, aqueous solutions concentration, and the carrier (D2EHPA) concentration in a liquid membrane. The results of the theoretical calculations were experimentally verified. 1. INTRODUCTION The subject of this investigation was the hybrid pertraction (HP) of univalent cations occurring in the multimembrane hybrid system (MHS) composed of two polymer cation-exchange membranes (CEMs) and a liquid membrane placed between. [1-3]. The transport mechanism involves a series of coupled cation exchange-diffusion processes in CEMs and counter transport of cations as mediated by the ionic carrier A fundamental description of this process can be formulated in the framework of the thermodynamic network analysis after taking into consideration all the specific physicochemical and phenomenological relationships that govern the membrane phenomena. The network of the local fluxes and capacitances (based on the bond-graph approach) allows the formulation of a relevant mathematical description of the time-evolution of all the concentrations resulting from the operation of MHS system. Having assumed or measured model parameters and experimental transport conditions, the mathematical model was numerically solved using the Berkeley Madonna (ver.8.0.1.) solver of ordinary differential equations. The results of model calculations of the transport characteristics as dependent on the initial conditions for pH, the aqueous solutions concentrations, and the carrier concentration in a liquid membrane were compared with the corresponding experimental results. brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Repository of Nicolaus Copernicus University