Compressible Ionized Natural 3D Interconnected Loofah Membrane for Salinity Gradient Power Generation

Area of Science:

• Materials Science
• Renewable Energy
• Electrochemistry

Background:

• Salinity gradient power (SGP) harvesting is a promising renewable energy source.
• Affordable and efficient ion-selective membranes (ISMs) are critical for practical SGP implementation.

Purpose of the Study:

• To develop novel, cost-effective ISMs from natural loofah sponge for SGP applications.
• To investigate the performance of loofah-derived anion-selective membranes (ASMs) and cation-selective membranes (CSMs).

Main Methods:

• Chemical modification of loofah sponge fibers to create charged functional groups.
• Compression and resin filling to form 3D interconnected nanochannels.
• Fabrication of ASMs and CSMs for ion transport and selectivity.
• Testing membrane performance in salinity gradient power generation.

Main Results:

• Loofah-based ISMs exhibit high hydrophilicity and superior ion conductivity.
• The membranes demonstrated effective ion selectivity via nanofluidic effects and Donnan exclusion.
• A maximum power density of 18.3 mW m^-2 was achieved using artificial seawater and river water.
• Stacked membranes generated a voltage of 1.55 V, showing excellent dimensional stability.

Conclusions:

• Natural loofah sponge is a viable precursor for fabricating high-performance, durable, and affordable ISMs.
• This study presents a sustainable approach for developing next-generation SGP generators.
• The developed ISMs hold significant potential for large-scale salinity gradient energy harvesting.