Nanofluidic osmotic power generation from CO2 with cellulose membranes

The diffusion of chemical species down concentration gradient is a ubiquitous phenomenon that releases Gibbs free energy. Nanofluidic materials have shown great promise in harvesting the energy from the diffusion of ions via reverse electrodialysis process. In principle, any chemicals that can be converted to ions can also be used for nanofluidic power generation. In this work, we demonstrate the power generation from the diffusion of CO2 into air using nanofluidic cellulose membranes. By dissolving CO2 in water, a power density of 87 mW/m2 can be achieved. Using monoethanolamine solutions to dissolve CO2, the power density can be increased to 2.6 W/m2. We further demonstrate that the waste heat released in the industrial processes and carbon capture processes can be simultaneously harvested with our nanofluidic membranes, increasing the power density to 16 W/m2 under a temperature difference of 30°C. Therefore, our work should expand the application scope of nanofluidic osmotic power generation and contribute to the carbon utilization and capture technologies.