A　hydroxyl-functionalized　covalent　organic　framework　(TzDa-COF)　was　synthesized　for　efficient　SO2　capture　via　room-temperature　Pressure　Swing　Adsorption　(PSA).　TzDa-COF　exhibits　an　ultrahigh　BET　specific　surface　area　(2100　m2·g−1),　crystallinity　and　porosity,　achieving　12.3　mmol·g−1　SO2　capacity　at　25　°C　and　1.0　bar,　with​　extremely　fast　adsorption　kinetics　and　high　SO2/CO2　and　SO2/N2　selectivities　(19.3　and　179.6)　predicted　by　Ideal　Adsorbed　Solution　Theory　(IAST).　Unlike　chemisorption-based　adsorbents,　TzDa-COF　operates　via　a　physical　adsorption-dominated　reversible　mechanism,　enabling　complete　desorption　under　ambient　PSA　conditions.　This　yields　superior　space–time　saturation　breakthrough　sulfur　capacity　compared　to　Mg-gallate　and　ZSM-5　zeolite,　while　maintaining　90.6　%　capacity　over　20　cycles.　The　high　crystallinity　and　large　BET　specific　surface　area　synergistically　facilitate　＇rapid　capture-mild　regeneration＇　cycle.　This　energy-efficient,　stable　adsorbent　offers　a　groundbreaking　solution　for　direct　flue　gas　desulfurization　systems,　thus　significantly　reducing　process　costs　and　advancing　green　air　purification　technologies.　©　2025　Elsevier　Ltd