Electrodialytic treatment of boron-containing wastewater with univalent permselective membranes

The electrodialytic treatment of boron-containing wastewater (industrial landfill leachate), of 63.5-76.5 mg/L of B concentration, was examined in our laboratory. Leachate was treated in two steps. In the first, slightly pre-acidified leachate was partially desalinated to remove ca 80% of total salinity. An ED unit, equipped with AMX and CMX Neosepta Co. membranes and 0.19 mm membrane-to-membrane distance, was applied. In the second, CMS and ACS Neosepta univalent permselective membranes were used, to avoid deep diluate demineralization, under alkaline conditions (pH = 9-10). Despite applying the univalent permselective membranes, the percentage of boron removed vs. electric charge curves shows a similar tendency to those observed for sulfate. The boron current efficiency reached 27.9% and boron flux across membrane 95 μg/cm2 h. These values are several times higher than reported in literature. The boron flux value (95.0 μg/cm2 h) obtained in optimal boron removal conditions is high enough to consider electrodialytic boron-containing water treatment as a potential boron removal method.