Bioinspired Dual-Electric-Channel Membrane for Efficient Photothermal Evaporation and Ion-Selective Crystallization

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Mangrove plants exhibit efficient salt secretion mechanisms.
• Existing solar interfacial evaporation technologies face challenges with salt accumulation and selectivity.

Purpose of the Study:

• To develop a biomimetic graphene oxide/polyamide (GO/PA) membrane for integrated water evaporation, ion separation, and salt crystallization.
• To leverage dual-electric channels (DEC) for enhanced ion selectivity and reduced membrane fouling.

Main Methods:

• Fabrication of a GO/PA composite membrane with integrated photothermal and ion-selective properties.
• Utilizing DEC for active ion transport and crystallization at membrane edges.
• Testing the membrane's performance in solar-driven evaporation of high-salinity solutions.

Main Results:

• Selective crystallization of NaCl/Na2SO4 solutions up to 200 g/L with a NaCl mole fraction of 97.16%.
• Achieved a high crystallization rate of 202.2 g m-2 h-1 and water evaporation rate of 2.293 kg m-2 h-1.
• Demonstrated high thermal efficiency (95.53%) and excellent membrane robustness and versatility.

Conclusions:

• The GO/PA membrane effectively mimics mangrove salt secretion for efficient and selective solar desalination.
• The DEC mechanism significantly improves salt management and evaporation performance.
• This approach offers a promising advancement for solar interfacial evaporation in complex, high-salinity environments.