The　emission　of　volatile　organic　compounds　(VOCs)　significantly　contributes　to　air　pollution　and　poses　a　serious　threat　to　human　health.　Benzene,　one　of　the　most　toxic　VOCs,　is　difficult　for　the　human　body　to　metabolize　and　is　classified　as　a　Group　1　carcinogen.　The　development　of　efficient　adsorbents　for　removing　trace　amounts　of　benzene　from　ambient　air　is　thus　of　great　importance.　In　this　work,　we　studied　the　benzene　adsorption　properties　of　four　Zr-based　metal-organic　frameworks　(Zr-MOFs)　through　static　volumetric　and　dynamic　breakthrough　experiments.　Two　previously　reported　Zr-MOFs,　BUT-12　and　STA-26,　were　prepared　with　a　tritopic　carboxylic　acid　ligand　(H3L1)　functionalized　with　three　methyl　groups,　and　STA-26　is　a　2-fold　interpenetrated　network　of　BUT-12.　Two　new　isoreticular　Zr-MOFs,　BUT-12-Et　and　STA-26-Et,　were　synthesized　using　a　similar　ligand,　H3L2,　where　the　methyl　groups　are　replaced　with　ethyl　groups.　There　are　mesopores　in　BUT-12　and　BUT-12-Et　and　micropores　in　STA-26　and　STA-26-Et.　The　four　Zr-MOFs　all　showed　high　stability　in　liquid　water　and　acidic　aqueous　solutions.　The　microporous　STA-26　and　STA-26-Et　showed　much　higher　benzene　uptakes　than　mesoporous　BUT-12　and　BUT-12-Et　at　room　temperature　under　low　pressures.　Particularly,　the　benzene　adsorption　capacity　of　STA-26-Et　was　high　up　to　2.21　mmol/g　at　P/P0　=　0.001　(P0　=　12.78　kPa),　higher　than　those　of　the　other　three　Zr-MOFs　and　most　reported　solid　adsorbents.　Breakthrough　experiments　confirmed　that　STA-26-Et　could　effectively　capture　trace　benzene　(10　ppm)　from　dry　air;　however,　its　benzene　capture　capacity　was　reduced　by　90%　under　humid　conditions　(RH　=　50%).　Coating　of　the　crystals　of　STA-26-Et　with　polydimethylsiloxane　(PDMS)　increased　the　hydrophobicity　of　the　exterior　MOF　surfaces,　leading　to　a　more　than　2-fold　improvement　in　its　benzene　capture　capacity　in　the　breakthrough　experiment　under　humid　condition.　PDMS　coating　of　STA-26-Et　likely　slowed　down　the　water　adsorption　process,　and　thus,　the　adsorbent　afforded　more　efficient　capture　of　benzene.　This　work　demonstrates　that　modifying　both　the　interior　and　exterior　surfaces　of　MOFs　can　effectively　enhance　their　performance　in　capturing　trace　benzene　from　ambient　air,　even　under　humid　conditions.　This　finding　is　meaningful　for　the　development　of　new　adsorbents　for　effective　air　purification　applications.　©　2024　American　Chemical　Society.