Understandings on design and application for direct air capture: From advanced sorbents to thermal cycles

Abstract

Direct air capture (DAC) plays a crucial role in the carbon removal portfolio and is expected to capture over 980 MtCO2 to reach the net zero target. Despite being introduced in 1999, large-scale DAC application remains challenging. Nevertheless, various research efforts regarding material development, process construction, and application continue to expand. In 2013, our group at Zhejiang University initiated research on DAC using sorption methods. Our research focuses on advanced sorbents such as quaternary ammonium and chemical sorbents for moisture swing adsorption (MSA) and thermal-driven adsorption cycles. The working mechanism of MSA, the interfacial and structural characteristics of sorbents, and their effects on sorption performance are further analyzed. Furthermore, emphasis is placed on the significance of thermal integration in DAC, and a thermodynamic analysis is established to balance the thermal cycle and practical heat utilization of DAC. Different innovative applications of DAC are proposed based on the materials and working cycles. This account highlights that the co-development of materials, thermal cycles, and applications will facilitate the rapid deployment and engineering realization of DAC. It aims to clarify the critical challenges in DAC, and our group at Zhejiang University is committed to continuously contributing to this promising field.