A　magnetic　covalent　organic　framework　Fe3O4@BM　was　prepared　with　melamine　and　4–4′-biphenyldialdehyde　as　monomers　and　used　as　adsorbent　for　Ag　NP　removal.　Fe3O4@BM　was　characterized　by　zeta　potential　analysis,　transform　infrared　spectrometry,　X-ray　diffraction,　thermogravimetric　analysis,　contact　angle,　and　N2　adsorption–desorption.　Fe3O4@BM　possessed　plentiful　amino　groups,　positive　potential,　and　rapid　separation　performance,　making　it　a　promising　adsorbent　for　silver　nanoparticles.　The　adsorption　process　followed　the　pseudo-second-order　kinetic　equation　and　Langmuir　isotherm　model.　The　maximum　adsorption　capacity　of　Ag　NPs　calculated　by　the　Langmuir　isotherm　model　was　544.9 mg/g.　The　adsorption　product　Fe3O4@BM@Ag　could　be　recycled　and　efficiently　catalyze　the　degradation　of　4-nitrophenol　within　6 min.　Meanwhile,　the　recycled　Fe3O4@BM@Ag　could　also　be　used　as　a　surface-enhanced　Raman　substrate　for　DTNB　detection,　and　the　limit　of　detection　of　DTNB　reached　as　low　as　10–7 mol/L.　This　work　prepared　a　promising　adsorbent　Fe3O4@BM　for　Ag　NP　adsorption　and　provided　a　sustainable　approach　for　the　recycling　of　the　adsorption　product　Fe3O4@BM@Ag.　©　2022,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.