Abstract: To address climate change caused by carbon emissions, CO₂ solid adsorbents have entered a peak development period. To compare the application potential of various adsorbents in carbon dioxide direct air capture technology(DAC), the modification and properties of carbon-based adsorbents, metal-based adsorbents, metal-organic framework(MOFs) adsorbents, molecular sieve adsorbents, as well as resin and sepiolite adsorbents are analyzed. The study reveals that carbon-based adsorbents feature simple synthesis and wide-ranging raw materials. After modification, they can exhibit favorable adsorption performance, but their service life needs improvement. Metal-based adsorbents show high adsorption capacity and rapid reaction kinetics, yet their high adsorption/desorption temperatures lead to substantial energy consumption. MOFs adsorbents are adaptable to various active substances, demonstrating good modification effects, but they are constrained by process difficulties and raw material costs, hindering large-scale application. Molecular sieve adsorbents can efficiently treat low-concentration CO₂, with mature synthesis and regeneration technologies. Comprehensively, molecular sieve adsorbents show the greatest application potential in DAC. Through optimizing the synthesis and modification technologies of molecular sieves and investigation the adsorption-regeneration process flow, high-benefit large-scale application of DAC can be achieved.

Key words: carbon dioxide, direct air capture, adsorbent, modification