Magnetic　porous　Fe3O4/MRCS　polymer　composite　was　prepared　by　reacting　melamine-formaldehyde　resin　with　chitosan　in　the　present　of　amino　modified　Fe3O4　nanoparticles　and　used　as　adsorbent　for　acid　red　18　azo　dye　removal.　The　Fe3O4/MRCS　was　characterized　by　TEM,　SEM,　XRD,　TGA　and　BET　analysis.　The　Fe3O4/MRCS　possessed　high　BET　surface　area　(226.6　m(2)/g),　characteristic　pore　properties　and　facile　magnetic　separation　function.　The　average　pore　width　is　6.5　nm　and　the　pore　volume　was　0.68　cm(3)/g.　The　Fe3O4/MRCS　presented　enhanced　high　adsorption　performance　toward　acid　red　18.　It　removed　99.　65%　of　acid　red　18　(100　mg/L)　when　the　adsorbent　amount　was　over　0.8　g/L.　It　was　found　the　absorption　was　depended　on　pH　and　the　removal　efficiency　decreased　with　pH　increased.　The　maximum　adsorption　capacity　of　acid　red　18　reached　as　high　as　301.0　mg/g.　The　adsorption　kinetic　followed　the　pseudo-second-order　kinetics　model　and　the　activation　energy　of　the　adsorption　process　was　38.40　kJ/mol.　The　adsorption　isotherms　were　best　fitted　to　the　Redlich-Peterson　isotherm　equation.　Thermodynamic　studies　indicated　the　adsorption　process　was　spontaneous　and　endothermic　in　nature.　The　adsorption　mechanism　study　showed　the　adsorption　was　a　heterogeneous　chemisorption　process　with　multiple　interactions,　involving　pore　filling,　electrostatic　attraction,　affinity　interaction,　intra-particle　diffusion,　pi-pi　interaction　and　polymer　chain　inclusion　and　polymer　net　trapping.　In　comparison　with　other　reported　adsorbents,　the　magnetic　porous　Fe3O4/MRCS　showed　superior　adsorption　performance　for　acid　red　18　removal.　(C)　2019　Elsevier　B.V.　All　rights　reserved.