Prussian blue assembled on graphene oxide for enhanced capacitive deionization and water disinfection

Capacitive deionization (CDI) with water disinfection materials is an energy-efficient technology for the simultaneous desalination and bio-decontamination of brackish water. However, desalination capacity is always limited by the mechanism of ion electrosorption within the electrical double layer. Recently, the water disinfection ability of CDI has been demonstrated through the functionalization of electrode materials with antimicrobial compounds. To achieve highly efficient and low-cost capacitive deionization and disinfection (CDID) performance, we propose a facile strategy for the fabrication of a graphene oxide/polyaniline/Prussian blue (GO/PANI/PB) nanocomposite. This nanocomposite exhibits a high Brunauer–Emmett–Teller surface area (148.08 m² g⁻¹), mesopore volume (34.02 cm³ g⁻¹), and pore volume (0.66 cm³ g⁻¹), making it suitable as a Faradaic electrode in the CDI and CDID systems. The obtained GO/PANI/PB electrode exhibits a high desalination capacity of 91.6 mg g⁻¹ and superior desalination ratio of 3.05 mg g⁻¹ min⁻¹ at 1 A g⁻¹. Furthermore, the GO/PANI/PB electrode has a bacterial (Escherichia coli) removal and inactivation efficiency of 94.0% ± 3.1% without the use of other disinfectants. This is ∼7 times higher than the antibacterial efficiency of active carbon electrodes under the same CDI conditions. The proposed strategy is the first to exploit simultaneous deionization and disinfection without using disinfectants, offering the potential of using PB-based Faradaic electrodes for eco-friendly and high-efficiency water desalination and disinfection in future CDID technology.[Figure not available: see fulltext.]