Enhanced Desalination Performance by a Novel Archimedes Spiral Flow Channel for Flow-Electrode Capacitive Deionization

Abstract

As an emerging desalination technology, flow-electrode capacitive deionization (FCDI) has aroused extensive attraction due to its advantage of pseudoinfinite adsorption capacity. However, some problems still remain in the traditional FCDI devices, i.e., its streaming and seeping quality which has severely limited the progress. Herein, some improvements were achieved by changing the direction of saline water in spacer. Furthermore, the Archimedes spiral flow channel model was introduced to improve the flow behavior of carbon slurry in the FCDI unit cell for the first time, which has vastly boosted the desalination performance of FCDI devices. The computational fluid dynamics (CFD) simulation revealed the more uniform velocity distribution and longer residence time of carbon slurry in spiral flow channels to enhance the desalination, while the flow rate of carbon slurry in a straight line is faster but slower in the corner of serpentine flow channels, causing a negative effect on the desalination performance. After long-term continuous desalination in 3.5 g L–1 NaCl solution at 2.4 V, 99.88% of salt removal efficiency was achieved with a superior salt removal rate of 4.06 μmol cm–2 min–1 and 98.9% charge efficiency for the spiral flow channel FCDI device, demonstrating a stable desalination performance.

Enhanced NH4+ Removal and Recovery from Wastewater Using Na-Zeolite-based Flow-Electrode Capacitive Deionization: Insight from Ion Transport Flux

“…The flow channel of a spiral pattern is superior to that of the widely used serpentine pattern in terms of hydraulic performance, which can considerably reduce heat loss and prevent channel blockage. In addition, compared with the single spiral shape flow channel reported by Zhang et al, 36 the double spiral shape flow channel not only avoids the need for a hole through the current collector and end plate for creating an outlet for the FE suspension but also further improves the hydraulic condition. The effective contact area (A eff ) between each IEM and the FE channel was 77.0 cm 2 .…”

Surface Engineering of Electrified MXene Filter for Enhanced Phosphate Removal

“…9,10 Additionally, creating sites on the filter with high phosphate affinity during the electrofiltration operation also may address issues associated with limited removal kinetics. 11,12 To this end, previous research has used materials that have a two-dimensional (2D) structure with substantial specific surface area and copious sites for sorption as model sorbents for water decontamination. 13 For example, graphene oxide (GO) has attracted considerable interest in the removal of phosphate, heavy metal, and organic dyes from wastewater.…”

“…Electrochemical sorption of phosphate with only mild operating conditions and no additional chemicals offers an environmentally friendly approach for water purification. , The electrofiltration system has the advantage of mass transfer that is enhanced by forced convection, which provides much better decontamination of ultralow concentrations of phosphate than standard decontamination systems that operate in a batch mode. , Additionally, creating sites on the filter with high phosphate affinity during the electrofiltration operation also may address issues associated with limited removal kinetics. , To this end, previous research has used materials that have a two-dimensional (2D) structure with substantial specific surface area and copious sites for sorption as model sorbents for water decontamination . For example, graphene oxide (GO) has attracted considerable interest in the removal of phosphate, heavy metal, and organic dyes from wastewater .…”

A Hexagonal Honeycomb-Shaped Flow Channel for High-Efficient Desalination and Flowability in Flow-Electrode Capacitive Deionization

“…The hydrodynamic boundary layer formed by active particles on the surface of the channel wall is vital to the construction of charge percolation networks and electron transport . Currently, several flow channel geometries were developed for the FCDI system, such as the spiral flow channel, titanium mesh-membrane assembly, three-dimensional foam current collector, and honeycomb-shaped lattice structures . Cho et al developed a highly compact and scalable three-dimensional desalination cell by utilizing a honeycomb porous lattice of scaffolds, allowing enhanced salt removal capacity .…”