Direct Air CO2 Capture via Hot Water Cycling of Poly(ethyleneimine)/Silica Hollow Fiber Sorbents

Hollow fiber sorbents containing amine-infused mesoporous silicas are promising materials for CO2 capture from ambient air due to the ease of heat integration and low pressure drops. In this study, hot water is utilized as the heat source for regenerating polysulfone-silica-poly(ethyleneimine) fibers prepared with a hybrid polyvinylidene chloride/styrene-butadiene lumen barrier. The fiber sorbents are characterized using breakthrough and desorption measurements to evaluate the optimal adsorption and desorption times. Rapid temperature swing adsorption cycles are completed to evaluate the stability, productivity, and swing capacities of the fiber sorbents. In the final cycle, a swing capacity of 0.72 mmol gfiber-1 under 400 ppm CO2 flow at 22 °C and 45% relative humidity was reached, with a CO2 recovery of 68%.