Quaternized Chitosan/PVA Aerogels for Reversible CO₂ Capture from Ambient Air

Developing inexpensive and highly efficient CO₂ air capture technologies is an important solution for solving the greenhouse problem. In this work, we used the low-cost quaternized chitosan (QCS)/poly(vinyl alcohol) (PVA) hybrid aerogels with quaternary ammonium groups and hydroxide ions to reversibly capture CO₂ from ambient air by humidity swing. The CO₂ capture capacity and adsorption rate of the aerogels were investigated over the temperature range 10-30 °C. The CO₂ capture capacity of the aerogels was measured to be about 0.18 mmol/g, which is 38% higher than the state-of-the-art commercial membrane. In addition, we proposed a modified pseudo-first-order kinetic model considering both the CO₂ adsorption and the H₂O desorption, which describes the experimental results very well. For the first time, the moisture-swing CO₂ adsorbent is built by low-cost biomass material, which opens up a new approach for the design of the moisture-swing CO₂ adsorbent.