Modeling of sodium acetate recovery from aqueous solutions by electrodialysis

The main engineering parameters (i.e., ion transport numbers in solution and electro‐membranes; effective solute and water transport numbers; effective membrane surface area, membrane surface resistances, and limiting current intensity) affecting the recovery of sodium acetate from model solutions by electrodialysis (ED) were determined in accordance with a sequential experimental procedure. Such parameters allowed a satisfactory simulation of a few validation tests carried out under constant or step‐wisely variable current intensity. The performance of this ED process was characterized in terms of a current efficiency (Ω) of about 93% in the constant‐current region, a water transport number (tW) of about 15, and a specific energy consumption (ε) increasing from 0.14 to 0.31 kWh/kg for a solute recovery yield of 95% as the current density (j) was increased from 112 to 337 A/m2. The specific resistance of the anion‐ or cation‐exchange membranes were found to be three or two times greater than those measured in aqueous NaCl solutions and are to be used to design and/or optimize ED stacks involved in the downstream processing of acetic acid fermentation broths. © 2005 Wiley Periodicals, Inc.