(471a) Transport Analysis of an Integrated Artificial Photosynthetic System for Direct Capture and Reduction of CO2 from Air

The effect of anthropogenic emissions of CO₂ on the climate change is becoming progressively prevalent. The current concentration of CO₂ in the air is 409.11 ppm, which is increasing at a rate of ~1.9 ppm per year. There exist several technologies such as amine scrubbing, oxyfuel combustion, and calcium looping to capture CO₂ from flue gases, which are inherently energy intensive. However, there are only a few techniques such as moisture-swing adsorption that can capture CO₂ from the air but requires modulation of humidity and downstream separation. The captured CO₂ can be either sequestered at the storage site or chemically transformed into a usable product. Integrating CO₂ capture with reduction not only eliminates the need for additional transportation and storage but also increases the efficiency of CO₂ capture. Here we provide a conceptual design of an integrated system where an anion-exchange resin for CO₂ capture is directly connected to a photo/electrochemical cell for CO₂ reduction. The dry-side of the resin captures CO₂ from the air and produces a high concentration of HCO₃^- diffusing towards the wet-side of the resin, where HCO₃^- converts back to CO₂ at the attached cathode to produce fuels. The limiting current density of an integrated system as a function of resin properties, catalysts activity and selectivity, electrolyte pH, physical dimensions and relative humidity are simulated using COMSOL Multiphysics. The limiting current density increases with increasing the resin conductivity, and mass-transfer coefficient of CO₂ in air. The efficiency of such integrated system using air as well as flue gas will be discussed.