Novel magnetic graphene oxide decorated with persimmon tannins for efficient adsorption of malachite green from aqueous solutions

•Magnetic graphene oxide decorated with persimmon tannin composites (Fe3O4/PT/GO) was used for malachite green (MG) adsorption.•The adsorption equilibrium, kinetics and thermodynamics were comprehensively studied.•The Fe3O4/PT/GO adsorbent showed high adsorption capacity for MG.•The adsorbent displayed excellent regeneration and reusability properties.•This adsorbent can be employed for the removal of cationic dyes from wastewater.