Efficient　mercury　ion　removal　from　water　is　a　primary　challenge　for　ecosystem　protection　and　public　health.　This　study　improves　the　effect　of　functional　groups　on　mercury　removal　by　functionalizing　and　tuning　the　molecular　structure　of　poly(pyrrole　ethene)　(PPyE)　with　chloro,　i.e.　poly[pyrrole-2,5-bis(2-chloroethane)]　(PPyCE),　and　imino　groups,　i.e.　poly[pyrrole-2,5-bis(2-ethylamino　ethane)]　(PPyEE).　The　resultant　functionalized　poly(pyrrole　methane)s　can　efficiently　remove　mercury　(Hg(II))　from　water　with　uptake　capacities　of　684.59　mg/g　(chloro　functionalized)　and　389.57　mg/g　(imino　functionalized)　at　room　temperature,　which　was　much　higher　than　that　of　unfunctionalized　poly(pyrrole　ethane)　(only　122.74　mg/g).　The　functionalized　poly(pyrrole　methane)s　had　additional　benefits　of　low　usage,　excellent　selectivity　for　mercury　ions　and　anti-coexisting　ion　interference　performance.　Furthermore,　the　chloro　functionalized　poly(pyrrole　methane)s　also　exhibited　exceptional　recyclability　for　the　adsorption　capacity　remaining　above　80%　of　the　original　after　5　regeneration　cycles.　These　results　were　largely　attributed　to　the　functional　groups　of　chloro　and　imino　in　the　material　backbone　as　chelating　sites　to　bind　with　mercury,　which　was　confirmed　by　Fourier　Transform　infrared　spectroscopy　(FT-IR)　and　X-ray　photoelectron　spectroscopy　(XPS)　before　and　after　mercury　capture.　This　study　provides　a　potential　strategy　for　designing　and　tuning　the　adsorbents　to　efficiently　remove　mercury　and　other　heavy　metal　ions　from　aqueous　solutions　for　environmental　remediation.　©　2022　Elsevier　B.V.