Synthesis and Characterization of Activated Carbon Co-Mixed Electrospun Titanium Oxide Nanofibers as Flow Electrode in Capacitive Deionization

Abstract

Flow capacitive deionization is a water desalination technique that uses liquid carbon-based electrodes to recover fresh water from brackish or seawater. This is a potential second-generation water desalination process, however it is limited by parameters such as feed electrode conductivity, interfacial resistance, viscosity, and so on. In this study, titanium oxide nanofibers (TiO2NF) were manufactured using an electrospinning process and then blended with commercial activated carbon (AC) to create a well distributed flow electrode in this study. Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray (EDX) were used to characterize the morphology, crystal structure, and chemical moieties of the as-synthesized composites. Notably, the flow electrode containing 1 wt.% TiO2NF (ACTiO2NF 1 wt.%) had the highest capacitance and the best salt removal rate (0.033 mg/min·cm2) of all the composites. The improvement in cell performance at this ratio indicates that the nanofibers are uniformly distributed over the electrode’s surface, preventing electrode passivation, and nanofiber agglomeration, which could impede ion flow to the electrode’s pores. This research suggests that the physical mixture could be used as a flow electrode in capacitive deionization.

Insights into the Particle Hydrophilicity and Electrical Conductivity for the Construction of a Highly Efficient Electrical Percolation Network in Flow Electrode Capacitive Deionization

“…Fresh water that can be directly utilized in nature is limited, and the ongoing population growth, water pollution, and climate change further decrease the availability of fresh water. − To deal with the shortage of fresh water, a series of desalination technologies, including thermal treatment and membrane separation, have been widely applied. Thermal treatment such as multistage flash stands out for its high desalination efficiency, but the corrosion of equipment and high energy consumption increase the operation cost.…”