Phosphate　removal　from　water　relies　mainly　on　the　effective　adsorbent.　Iron-loaded　magnetic　alginate-chitosan　double-gel　interpenetrated　porous　beads　(M-IACBs)　were　prepared　from　waterworks　iron　sludge,　magnetic　nanoparticles,　sodium　alginate,　and　chitosan　where　magnetic　nanoparticles　were　also　synthesized　from　iron　sludge.　The　interpenetrating　network　constructed　by　sodium　alginate　and　chitosan　improves　the　stability　of　the　beads,　while　iron　sludge　acts　as　the　main　functional　body　for　phosphate　adsorption.　M-IACBs　with　uniform　size　(~　2　mm)　and　strong　saturation　magnetization　intensity　(~　15.0　emu/g)　maintain　good　stability　in　the　pH　range　of　4–8.　They　have　good　selectivity　for　phosphate　in　the　presence　of　competing　ions.　The　phosphate　adsorption　by　the　beads　followed　the　Langmuir　model,　indicating　that　the　adsorption　was　dominated　by　monolayer　adsorption,　and　the　fitting　yielded　a　maximum　phosphate　adsorption　capacity　of　18.5　mg/g.　The　pseudo-second-order　model　better　agrees　with　the　experimental　data.　The　adsorption　properties　of　iron　sludge　and　beads　were　compared.　Granulation　was　found　to　enhance　the　availability　of　the　adsorbent　but　slow　down　the　adsorption　kinetics.　The　adsorption　mechanisms　of　phosphate　are　ligand　exchange　and　electrostatic　attraction.　This　study　provides　a　reference　pathway　for　phosphate　removal　and　resource　utilization　of　iron　sludge　in　waterworks.　©　2022　Elsevier　B.V.