Electrodialysis for removal of chromium (VI) from effluent: Analysis of concentrated solution saturation

• Published in: Journal of environmental chemical engineering 2019-10, Vol.7 (5), p.103380, Article 103380
• Main Authors: dos Santos, Camila Silveira Lamanes, Miranda Reis, Miria Hespanhol, Cardoso, Vicelma Luiz, de Resende, Miriam Maria
• Format: Article
• Language: English
• Subjects: Chromium (VI) removal; Ion-exchange membranes; Separation technique; Sequential treatment; Volume reduction of final effluent
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2019.103380

Electrodialysis (ED) was used as a sequential treatment of a hybrid anaerobic bioreactor to evaluate the saturation of the concentrated solution flow in its efficiency. The chromium (VI) in the anion form (Cr2O72−) at initial concentrations of 10, 65 and 100 ppm were used in feed streams. The operating flows were of 20, 60 and 60 L h-1 for electrolyte, feed and concentrated solution, respectively. The current limit used was of 0.03 A. The chromium (VI) removal was approximately 99% ± 0.5% with 75 min of operation. For an initial volume of effluent equal to 76 L the final volume of wastewater concentrated solution was equal to 4 L, with a maximum concentration of chromium (VI) of 570 ppm. The results showed that with this concentrated solution it was not possible to remove the ion Cr2O72− in the feed even with clean membranes, that is, the concentrated solution concentration can be considered a limiting variable of the electrodialysis.