Acid/Base Production via Bipolar Membrane Electrodialysis: Brine Feed Streams to Reduce Fresh Water Consumption

The increasing demand for environmentally friendly production of alkaline and acidic materials has boosted the advancement of electrodialysis with bipolar membranes (EDBM) as an efficient and sustainable technology. In this context, this study aims to optimize the EDBM system performance and minimize its environmental impact. Specifically, this work focuses on the use of concentrated brines in alkaline or acid channels as innovative EDBM schemes to reduce freshwater consumption. Two different commercial monopolar and bipolar membrane sets were tested (Fumatech and SUEZ) showing a difference in productivity ratios, between them, ranging from 9% to 40%. The use of brine in the compartments leads to a reduction in the water footprint and highlights potential pathways to enhance the overall EDBM system sustainability. Remarkably, introducing a brine in the alkaline channels does not affect energy performance while achieving 50% reduction in freshwater consumption. In contrast, feeding brine into acid channels leads to a performance decline. This research provides a holistic perspective on the interplay between technical and environmental performance of EDBM process, providing a valuable guide for future research and paving the way for novel membranes, long-term stability, and strategies to minimize energy consumption and environmental impact, toward sustainable industrial practices.