Development of a ventilated structure spacer for salinity mitigation in brackish water using flow electrode...

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Flow-electrode capacitive deionization (FCDI) is a promising technology for water desalination.
• Spacer design critically impacts ion transport and concentration polarization in FCDI systems.
• Existing woven mesh spacers can lead to high hydraulic and ohmic resistance.

Purpose of the Study:

• To introduce and evaluate a novel ventilated spacer (V-FCDI) for FCDI systems.
• To compare the performance of V-FCDI against traditional woven mesh spacers (W-FCDI).
• To investigate the impact of spacer architecture on concentration polarization and energy efficiency.

Main Methods:

• Computational fluid dynamics (CFD) simulations to analyze spacer hydrodynamics.
• Experimental assessment of V-FCDI and W-FCDI performance under varying flow rates and applied voltages.
• Systematic comparison of salt removal rate, desalination capability, and energy consumption.

Main Results:

• The V-FCDI design effectively mitigates concentration polarization through localized flow disruption.
• V-FCDI demonstrated a 9.0% increase in salt removal rate and a 9.5% higher voltage-driven desalination capability.
• Significant reductions in energy consumption were observed: 11.2% for specific electrical energy and 18.8% for specific pumping energy.

Conclusions:

• The ventilated spacer architecture offers superior performance compared to traditional woven mesh spacers.
• V-FCDI presents a viable pathway for developing highly energy-efficient brackish water desalination systems.
• This study establishes new design principles for optimizing FCDI performance.