Modelling the electrodialytic recovery of sodium lactate

Abstract

The recovery of sodium lactate from model solutions by ED (electrodialysis) was studied using a sequential experimental procedure so as to assess the main engineering parameters (i.e. ion transport numbers in solution and electro-membranes, effective solute and water transport numbers, effective membrane surface area, surface resistances and limiting current intensity) affecting ED stack design and/or optimization. Of the major factors that determine the performance of this ED process, Omega (the current efficiency) was about 88% in the constant-current region, while epsilon (the specific energy consumption) increased from 0.14 to 0.31 kWh x kg(-1) for a solute recovery yield of 95% and j (current density) increasing from 112 to 337 A x m(-2). The specific-resistance values of the anion- or cation-exchange membranes were found to be five or two times greater respectively than those extracted from literature and measured in aqueous NaCl solutions.

Application of Design of Experiments to the Analysis of Fruit Juice Deacidification Using Electrodialysis with Monopolar Membranes

“…For higher values, the voltage deviated from the line approximating the first linear zone, and this deviation occurred for lower current values the lower the concentration (or corresponding conductivity) of the solution. This behavior is consistent with previous results obtained using strong electrolytes [ 16 , 17 ] or the sodium salts of monoprotic, diprotic and poliprotic acids [ 18 , 19 , 20 , 21 , 22 ]. To facilitate the determination of the limiting current, the experimental voltage-current data were plotted on a Cowan and Brown diagram ( Figure 2 b).…”