BACKGROUND:　The　release　of　natural　estrogen　17　beta-estradiol　(E2)　to　the　aquatic　environment　is　a　matter　of　concern.　Batch　experiments　were　conducted　to　study　the　adsorption　of　E2　by　anaerobic　granular　sludge　(AnGS)　combined　with　zero-valent　iron　(ZVI).　The　enhancement　mechanism　of　ZVI　for　E2　adsorption　by　AnGS　was　also　analyzed.　RESULTS:　The　E2　adsorption　efficiency　of　AnGs　with　ZVI　was　48%　higher　than　that　without　ZVI.　The　optimal　conditions　for　high　E2　adsorption　efficiency　(92.21%)　and　high　equilibrium　adsorption　capacity　(4.92　mu　g　g(-1)　VSS)　were　r(ZVI/AnGS)　1.33,　pH　6,　and　temperature　25　degrees　C.　E2　adsorption　by　ZVI/AnGS　was　a　spontaneous　and　exothermic　process,　well　described　by　the　Freundlich　isotherm.　CONCLUSION:　The　addition　of　a　suitable　amount　of　ZVI　enhanced　E2　adsorption　by　AnGS.　(c)　2017　Society　of　Chemical　Industry