Optimizing Electrodialytic Recovery of Mineral Ions from Bittern Wastewater Using D-Optimality Design

Electrodialysis has been proven effective due to its high selectivity for separating monovalent and divalent ions. This study statistically evaluated the simultaneous electrodialytic recovery of mineral ions from bittern wastewater. The objective was to investigate the effect of cell number, anode materials, and applied voltage to optimize mineral ion recovery. A D-optimality design response surface methodology was performed to estimate the model parameter and identify the factors contributing to mineral ions recovery. The effects of independent variables and their interactions on the responses were investigated using ANOVA. All developed models were highly significant, with a p-value of <0.0001. The applied voltage was considered very important for the recovery process of all mineral ions as it affects the driving force of ion migration through the ion-exchange membrane. The optimization analysis (desirability value of 0.967) revealed 12% Cl-, 14% SO42-, 0.7% Mg2+, and 21% Ca2+ recovery at the combination of 5-cells configuration, graphite electrode, and 9 V.