Magnetic　alginate-chitosan　porous　beads　based　on　iron　(Fe)　sludge　(M-ACFBs)　were　prepared　by　waterworks　iron　sludge,　sodium　alginate,　chitosan,　and　magnetic　nanoparticles.　The　magnetic　nanoparticles　were　also　synthesized　using　waterworks　iron　sludge　through　the　co-precipitation　method.　In　addition,　a　double　gel　network　of　sodium　alginate　and　chitosan　was　constructed　to　improve　the　pH　stability　of　the　beads.　At　the　same　time,　iron　sludge　served　as　the　functional　body　for　As(V)　adsorption.　The　beads　have　uniform　bead　size　(similar　to　2　mm),　high　specific　surface　area　(115.4　m(2)/g),　distinguished　mesopores　(5.7　nm　in　size),　and　strong　saturation　magnetization　(similar　to　15.0　emu/g).　The　ratio　of　magnetic　nanoparticles　to　iron　sludge　was　optimized,　and　the　effects　of　pH,　contact　time,　temperature,　and　coexisting　ions　on　As(V)　adsorption　effect　were　studied.　Also,　the　adsorption　kinetics　and　adsorption　isotherms　are　thoroughly　discussed.　The　adsorption　mechanism　of　M-ACFBs　on　As(V)　is　concluded　as　ligand　exchange　and　electrostatic　attraction,　and　the　maximum　adsorption　capacity　is　as　high　as　14.2　+/-　0.4　mg/g.　It　is　found　that　magnetite　(Fe3O4)　can　form　a　maghemite　(gamma-Fe2O3)　layer　in　an　oxygen-rich　environment,　and　at　the　surface　of　this　gamma-Fe2O3　layer,　Fe(II),　O-2,　and　As(V)　undergo　complex　redox　reactions,　leading　to　the　appearance　of　As(III),　which　leads　to　a　challenge　for　the　disposal　of　arsenic-loaded　adsorbents.　This　study　provides　a　reference　pathway　for　the　resource　utilization　of　backwash　iron　sludge　and　As(V)　removal　from　water.