Abstract <p>Recovery of clean water and valuable nutrients from wastewater was investigated using a flow electrode capacitive deionization (FCDI) process operated in short-circuited closed cycle (SCC) mode. Orthophosphate was selected as a model nutrient, and its removal and recovery were studied using carbon black (CB) and activated carbon (AC) as flow electrode. A narrow-channel crossflow reactor equipped with ion exchange membranes (IEMs) and turbulence-promoting netting was used for the investigation. The flow electrode materials were characterized using Brunner-Emmett-Teller (BET), Scanning Electron Microscope coupled with Energy Dispersive X-ray (SEM/EDX), X-Ray Diffraction (XRD), and X-Ray Photoelectron Spectroscopy (XPS). The effects of applied voltage, flow rate, flow electrode loading, and initial pH and feed concentration were systematically studied. A mathematical model was developed to predict the time-dependent phosphate concentration, demonstrating a strong correlation with the experimental data. Additionally, parameter optimization using Response Surface Methodology (RSM) revealed that applied voltage and initial pH significantly influenced phosphate removal, while physisorption was negligible compared to electrosorption. Close to ~92% phosphate removal efficiency was achieved using CB as flow electrode compared to ~80% for AC under the same operating conditions. These findings highlight the potential of FCDI with CB-based flow electrodes for effective wastewater treatment and nutrient recovery.</p> Highlights <p>• FCDI was used to recover clean water and nutrients from wastewater.</p> <p>• Electrosorption was the dominant phosphate removal mechanism.</p> <p>• Applied voltage and initial pH significantly influenced phosphate removal.</p> <p>• Carbon black flow electrode achieved ~92% phosphate removal.</p> <p>• Activated carbon flow electrode achieved lower (~80%) phosphate removal.</p>