A　novel　acid-base　bifunctional　adsorbent　was　synthesized　using　a　three-stage　process　involving　(i)　synthesis　of　MCM-41　mesoporous　silica　(MS)　carrier,　(ii)　acidic　modification　of　the　carrier　by　aluminum　isopropoxide　dosing　(Al-MS),　and　(iii)　basic　modification　by　amino　groups　post-grafting　(Al-MS2).　Large　spatial　hindrance　amino　groups　were　selected　for　the　basic　modification　step　to　avoid　spontaneous　recombination　and　neutralization　reactions　between　the　two　antagonist　functional　groups.　X-ray　diffraction,　transmission　electron　microscopy,　NH3-based　temperature-programmed　desorption,　Fourier　transform　infrared　spectroscopy,　and　N-2　adsorption-desorption　techniques　were　used　to　characterize　the　samples　obtained　at　each　step.　Then,　the　simultaneous　adsorption　capacities　of　lead　(Pb(II))　and　nitrate　(NO3-)　ions　were　investigated　and　compared.　The　results　revealed　that　Al-MS2　had　good　adsorption　efficiency　for　Pb(II)　and　NO3-,　achieving　maximum　adsorption　capacities　of　712　mu　mol/g　for　Pb(II)　and　1120　mu　mol/g　for　NO　at　pH　5.0.　The　proposed　mechanism　for　the　simultaneous　removal　of　Pb(II)　and　NO3-　by　the　adsorbents　were　also　discussed.　The　results　showed　that　Al-MS2　was　successfully　modified　with　two　antagonist　adsorption　groups,　thus　providing　a　new　strategy　for　designing　multifunctional　adsorbents　for　the　simultaneous　removal　of　toxic　metal　cations　and　anions　from　wastewater.　(C)　2015　Elsevier　B.V.　All　rights　reserved.