Study on robust absorption performance of hydrophilic membrane contactor for direct air capture

Increased atmospheric carbon dioxide (CO₂) concentration constitutes a growing environmental and health concern. The absorption of CO₂ from air requires a large gas–liquid contact area due to low driving force. Here, the membrane absorption was proposed to the removal of atmospheric CO₂ using a ceramic membrane contactor, while NaOH serves as absorbent, performance of ceramic membrane absorption was study. In hydrophilic membrane, NaOH concentration of 2 mol⋅L⁻¹ has the best absorption performance, which serves as initial concentration in absorption cyclic process, and when NaOH utilization reaches 75 %, it still has great absorption performance. In addition, suitable gas and liquid operating parameters of this work were also confirmed as 1000 mL⋅min⁻¹ and 1 mL⋅min⁻¹, respectively, corresponding mass transfer coefficient and CO₂ absorption flux is 2.6 mm⋅s⁻¹ and 0.096 mol⋅m⁻²⋅h⁻¹, respectively. The great absorption stability shows the huge potential of ceramic membrane contactor application for direct air capture.