Water Expulsion from Carbon Rods at High Humidity

Water Expulsion from Carbon Rods at High Humidity

Satish K. Nune, David J. Heldebrant, David Lao, Matthew J. Olszta, Yongsoon Shin, Xiao-Ying Yu and Juan Yao

Porous materials including carbons, silica gels and metalÐorganic frameworks (MOFs) are used for water management in various applications including catalysis, dehumidification and heating, ventilation and air conditioning (HVAC). Materials performance has been enhanced through chemical modifications, surface treatments or impregnation with hygroscopic salts. Regardless of the sorption behaviour/ mechanism, all porous materials exhibit an isotherm in which the quantity of water adsorbed increases with an increase in relative humidity. Recently, we have produced new class of carbon based materials the exhibited unique water adsorption phenomenon. The carbon-based rods can adsorb water at low humidity and spontaneously expel about half the adsorbed water at high relative humidity. Rods synthesised under different reaction conditions (eg., reaction temperature, and the amount of FeCl₃ catalyst used) have different morphology, size and exhibited different RH for the onset of evaporation and amount of water expelled. We will present the physical and spectroscopic evidence for this behavior, carbon-based rod growth mechanism and its potential applications.