Biochar　has　a　good　adsorption　ability　for　perrhenate　(ReO4−),　which　can　be　attributed　to　its　abundant　oxygen-containing　groups,　yet　the　effects　of　oxygen-containing　groups　on　ReO4−　adsorption　are　still　unclear.　Here,　the　interaction　of　ReO4−　and　acidic/basic　oxygen-containing　groups　(hydroxyl,　carboxyl,　pyrone　and　chromene)　on　biochar　were　investigated　by　density　functional　theory　(DFT)　calculation　with　conductor-like　screening　model　(COSMO).　According　to　the　calculated　results,　it　was　evidenced　that　the　adsorption　of　oxygen-containing　group　functionalized　BC　towards　ReO4−　was　gradually　strengthened　as　decreased　pH,　and　the　protonated　positively　charged　oxygen-containing　groups　presented　stronger　chemisorption　to　ReO4−　mainly　through　electrostatic　interaction,　complexation　and　atomic　orbital　hybridization.　The　protonated　hydroxyl　and　carboxyl　and　the　protonated　etheric　oxygen　of　pyrone　and　chromene　can　offer　favorable　binding　sites　to　ReO4−.　Compared　with　the　acidic　oxygen-containing　groups,　the　higher　adsorption　energy　values,　and　the　larger　Mayer　bond　order　indexes　of　interacting　atoms　identified　that　the　basic　oxygen-containing　groups　have　stronger　affinity　with　ReO4−.　Pyrone　had　the　strongest　adsorption　stability　toward　ReO4−.　Our　results　can　provide　new　ideas　into　the　design　and　preparation　of　separation　materials　for　ReO4−　or　the　other　anions　capture　from　the　aqueous　solution.　©　2019　Elsevier　B.V.