Review: Scenario-specific applications of direct air capture technology and system optimization approaches

As an indispensable negative emission solution within carbon neutrality strategies, the transition of direct air capture (DAC) technology from laboratory research to engineering deployment faces dual challenges of technical adaptability and system integration efficiency. This paper systematically analyzes the performance characteristics of mainstream technical pathways—including absorption, adsorption, and membrane separation methods—revealing high energy consumption and cost bottlenecks in DAC systems. It further identifies inadequate material cycling stability and poor energy supply compatibility as barriers to large-scale implementation. Building on this analysis, the study pioneers a multi-scenario application framework for industrial zones, urban areas, and remote regions, elucidating technology deployment across geographically distinct contexts. For system performance optimization, it establishes a cross-scale enhancement pathway spanning molecular-level interface modification, equipment-layer energy efficiency upgrades, and multi-energy supply systems. This is achieved through adsorbent modification (e.g., hydrophobic treatment of physical adsorbents, amine group dispersion reinforcement, and intelligent screening of porous materials), cascading waste heat utilization strategies, and multi-energy system integration. The work provides a theoretically rigorous and practically viable decision-support framework to advance DAC technology from unit innovation to system integration, offering critical guidance for accelerating the engineering implementation of negative emission technologies. • This study makes three significant contributions: • This research integrates the latest advances in direct air capture (DAC) technology and proposes methods to enhance economic viability and scalability, offering critical insights for overcoming cost-related challenges. • Pioneering a scenario-based perspective, it conducts a quantitative assessment of the adaptability of diverse DAC technologies across industrial, urban, and remote deployment contexts. • Synthesizing application modalities for DAC systems within distinct scenarios, the study identifies engineering deployment barriers and enabling pathways through a scenario-driven framework. • It proposes cross-scale optimization strategies for DAC systems, highlighting critical research gaps across multiple dimensions to provide actionable references for domain specialists.