Controllable ion transport by surface-charged graphene oxide membrane

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Ion transport is fundamental to biological processes and membrane technology.
• Graphene oxide (GO) is a promising 2D material for synthetic ion-transport membranes.
• Current GO membranes face challenges in excluding small ions during filtration.

Purpose of the Study:

• To investigate the manipulation of graphene oxide membrane surface charge for controlled ion transport.
• To enhance ion rejection and water permeance in GO-based membranes.
• To explore applications in water purification, biomimetic systems, and energy devices.

Main Methods:

• Fabrication of atomic-thick two-dimensional graphene oxide membranes.
• Deliberate regulation of membrane surface charge.
• Analysis of ion-surface interactions and transport mechanisms under pressure.
• Performance evaluation of water permeance and ion rejection rates.

Main Results:

• Highly charged GO membrane surfaces effectively repel high-valent co-ions.
• Permeation of low-valent counter-ions is restrained by balancing overall solution charge.
• Achieved remarkable enhancement in ion rejection.
• Demonstrated intrinsically high water permeance exceeding current nanofiltration limits.

Conclusions:

• Surface charge manipulation is a facile and scalable approach for controlling ion transport in GO membranes.
• The developed membranes show superior performance for selective ion separation.
• This strategy offers significant potential for water treatment, biomimetic ion channels, biosensors, and energy conversion technologies.