Abstract
A mathematical model is developed to express the desalination process of an aqueous solution consisting of a salt and a non-electrolyte by ED method. Under the assumption of plug flow in compartments, the ED process is analyzed to get the differential equations of mass balance in the flow length. And the transport equations of solutes and water through the membrane are deduced by irreversible thermodynamics approach. Then, under the condition of uniform current, the model composed of a first-order differential equation set is developed. While the model parameters including the transport coefficients, dimensions of ED equipment, operation conditions and characteristics of solutes are given, the model is solved by the numerical method. The variations of the current density, the concentrations of solutes and flow rates in dilute and concentrated compartments versus the flow length can be simulated by the model. And the required flow length can be calculated for the given desalination ratio. While there isn't non-electrolyte, the model is used to simulate the desalination process of salt solution. By comparing the ED experiments to the simulations, it is shown that the model is well employed to describe the actual desalination process. The effects of the initial values of variables in the model on desalination are simulated to attempt to instruct the actual ED process. And the general simulation of desalination process can be realized by the model. While the effect of concentration polarization on desalination process is reflected by the variation of membrane conductivity, the model is modified successfully.
