Rapid and Low-Energy Boron Removal Enabled by Carbon Cloth-Integrated Bipolar Membrane Electrodialysis

Boron removal has long been a technical challenge in desalination, particularly for the state-of-the-art reverse osmosis (RO) systems. Conventional methods, such as multistage RO or ion exchange, are typically energy-intensive and environmentally unfriendly, highlighting the need for sustainable and efficient boron removal strategies. In this study, we developed a carbon cloth-integrated bipolar membrane electrodialysis (C-BMED) technology, which combines bipolar membranes (BPMs) and carbon cloth within the electrodialysis (ED) cell. The carbon cloth serves as a solid-state buffer for maintaining OH^- in the desalination chamber, creating a locally alkaline environment that promotes boron ionization and removal. Its high conductivity also reduces system resistance, lowering energy consumption. Compared to RO, electrosorption (ES), and conventional ED, C-BMED overcomes the typical trade-off between the boron removal rate and energy efficiency, enabling continuous, rapid, and energy-efficient boron removal. Overall, the system achieves a boron removal rate exceeding 440 ng min^-1 cm^-2, with a specific energy consumption below 0.25 kWh g-B^-1.