A　novel　type　of　poly(maleic　anhydride)-graft-poly(vinyl　alcohol)　comb　polymer　functionalized　magnetic　nanoparticles　was　specially　designed　and　prepared　as　an　efficient　adsorbent　with　stimuli-responsive　reversible　adsorption/desorption　behavior　for　the　controllable　removal　of　heavy　metal　ions.　The　adsorption　capacities　of　comb　polymer　functionalized　magnetic　nanoparticles　toward　Ag+,　Ni2+,　Cd2+,　Pb2+　and　Co2+,　exhibiting　good　fits　to　Langmuir　isotherm　model　and　Pseudo-second　order　kinetic　model　with　correlation　coefficients　of　more　than　0.98,　were　0.8634,　0.8194,　0.8429,　0.6720　and　0.7682　mmol　g(-1)　respectively,　which　were　5　times　greater　than　those　of　linear　polymer　functionalized　magnetic　nanoparticles　due　to　the　contribution　of　topology　evolution.　Furthermore,　the　uptake　rate　of　comb　polymer　functionalized　magnetic　nanoparticles　toward　Ag+,　Ni2+,　Cd2+,　Pb2+　and　Co2+　increased　significantly　from　21.1%,　17.6%,　18.64%,　16.3%　and　15.68%　to　92.15%,　89.2%,　90.16%,　83.56%　and　84.52%　respectively　when　the　solution　pH　increases　from　4　to　7,　showing　a　pH-responsive　characteristic,　the　mechanism　of　which　was　elucidated　as　the　pH-driven　changes　in　electrostatic　interaction　and　molecular　morphology.　Good　sustainability　and　facile　reusability　were　practically　reflected　by　over　80%　uptake　efficiency　after　5　consecutive　absorption/desorption　cycles.　The　innovation　of　this　work　is　that　changing　molecular　topological　structure　of　the　polymer　can　significantly　contribute　to　excellent　adsorption　capacity　and　pH　responsiveness　to　remove　heavy　metal　ions　in　wastewater.　The　importance　of　this　study　is　to　offer　a　practical　cleaner　production　process　for　an　attractive　adsorbent　with　stimuli-responsive　adsorption　behavior　and　good　sustainable　application　through　innovative　molecular　design.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.