Comparative review of Direct air capture technologies: From technical, commercial, economic, and environmental aspects

Direct air capture (DAC) is set to play a crucial role in meeting climate change targets as most recent climate scenarios rely on its large-scale implementation. Nevertheless, despite this widespread consensus, DAC performance and impact have not been sufficiently investigated, which has resulted in hindering its wide-scale deployment for climate change mitigation initiatives. Here, we present a comparative review of different DAC technologies and examine their performance from a holistic perspective by considering different aspects, from technical, commercial, and economic to environmental. We classify DAC technologies into five main categories, namely (i) liquid scrubbing, (ii) solid sorbent, (iii) electrochemical, (iv) cryogenic, and (v) membrane, and within each category, various approaches can be employed. We explore key challenges involved in developing each DAC technology and compare their performance using up-to-date data. We then critically analyze the primary factors contributing to the inconsistencies arising from the economic assessment results and provide valuable guidelines for future studies. Overall, the present review can benefit researchers, engineers, and policymakers in obtaining a holistic understanding of these state-of-the-art technologies in addition to filling key gaps in the DAC field.