Novel High-efficiency adsorbent consisting of magnetic Cellulose-based ionic liquid for removal of anionic dyes

•A green high-efficiency adsorbent with imidazole-based ionic liquid to modify the magnetic particles and further enhanced electropositivity by amino-rich polyethylene imine was fabricated.•The adsorbent possesses affluent pore-structure caused by CaCO3 and considerable surface area.•The composite possesses outstanding adsorption performance of anionic dyes.•The adsorbent possesses excellent stability and recyclability.