Effect of selected process parameters on the electrodialytic separation and concentration of sulfuric acid using graphite electrodes

Present work explored the effect of current density and applied voltage along with the performance of graphite and SS 316 L as electrodes in the electrodialytic separation of sulfuric acid from model spent acidic solution. The study established that applied voltage in the range of 2-12 V was most suitable for maintaining current densities in the range 2-50 mA/cm(2) for different initial catholyte concentration. Around 90% acid separation could be achieved with more than 70% current efficiency. The electrical energy (kJ/l) required for the concentration enhancement of sulfuric acid by electrodialysis (ED) was estimated and was compared with the thermal energy required for the same by evaporation (EV). ED was found to be less energy intensive process. An economic evaluation of the integrated ED and EV was also carried out under present experimental conditions and the likelihood of which was found to be 21% and 24% more economical than standalone ED or EV respectively.