SEPARATION OF STRONG ACIDS BY ELECTRODIALYSIS WITH MEMBRANES SELECTIVE TO MONOVALENT IONS - AN APPROACH TO MODELING THE PROCESS

In this work some mixtures of sulphuric and nitric acids have been sep arated and concentrated by selective electrodialysis (SED) using heter ogeneous membranes. Selective membranes can now be used for the separa tion of acids since anion exchange membranes with reduced transport nu mber to multivalent ions are commercially available. The electric perf ormance of the system has been analyzed and a correlation between curr ent density, hydrodynamic parameters and concentration was established . The modelling of the SED experiments can be achieved with a good fit ting for various membrane configurations of industrial interest.Experi mental results show that at operation times lower than 40 minutes, the selective anion exchange membranes efficiently exclude the sulphate a nions. The nitrate anions fall to aero concentration at 60 minutes of operation and then the sulphate anions begin to cross through the memb rane.