Nanofluidic osmotic power generation from CO2 with cellulose membranes

Abstract

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 ionic diffusion via the reverse electrodialysis process. In principle, any chemicals that can be converted to ions can 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, etc., can be simultaneously harvested with our nanofluidic membranes, increasing the power density up 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.