Two keys to scalable direct air capture: water management and contactor productivity

Amine-based solid sorbent direct air capture (DAC) systems face two primary cost drivers: water management and contactor productivity. Water desorption during the regeneration step in temperature vacuum swing adsorption (TVSA) imposes significant energy penalties, while water uptake during regeneration in steam-assisted systems leads to substantial water losses. These penalties remain underexplored, particularly in steam-based processes, and are compounded by the limited availability of reliable CO 2 /H 2 O selectivity data under DAC conditions. More targeted efforts at the material level are needed to enhance CO 2 /H 2 O selectivity without sacrificing CO 2 capacity. On the productivity side, most DAC research has focused on sorbent materials, leaving contactor design comparatively underdeveloped. A critical gap remains in understanding how geometric parameters, such as channel width, wall thickness, and pattern spacing in complex architectures, govern key contactor productivity drivers like sorbent loading, pressure drop, mass transfer, and heat transfer. This gap has hindered the development of generalized contactor design principles for high productivity and low-cost DAC. While 3D printing and related technologies now enable increasingly complex contactor geometries, their potential cannot be realized without this foundational understanding. Moreover, trade-offs between structural complexity and manufacturing scalability are rarely quantified, making it difficult to evaluate the techno-economic viability of advanced contactor architectures. This opinion highlights the need to move beyond sorbent-centered design toward an integrated, multiscale approach that spans sorbent, contactor, and process levels for improved water management and contactor productivity in scalable DAC systems. • Amine solid DAC faces key cost drivers: water management and contactor productivity. • Water sorption and desorption during regeneration impose major challenges in DAC. • Targeted efforts are needed to improve CO₂/H₂O selectivity at the material level. • Limited geometric-performance insight hinders design principles for DAC contactors. • High contactor productivity must be achieved with scalable, low-cost manufacturing.