PEI-grafted magnetic cellulose for Cr(VI) removal from aqueous solution

A novel PEI-grafted magnetic cellulose (Fe3O4/MCC-PEI) with high amino density was prepared by grafting PEI onto the surface of magnetic cellulose in NaOH/urea aqueous solvent. The embedding of Fe3O4 into cellulose provided excellent magnetic responsiveness for recycling the adsorbent in the magnetic field. The adsorbent for Cr(VI) removal from aqueous solution overcame the disadvantages of adsorbent like difficult recycling, poor regeneration performance and low removal rate at low Cr(VI) concentration. Therefore, the as-prepared Fe3O4/MCC-PEI showed high Cr(VI) adsorption capacity (198.8 mg/g) which could achieve adsorption equilibrium within 10 min, and the removal rate could reach 100% at low Cr(VI) concentration (less than 1.0 mg/L), demonstrating that the high amino density (7.85 mmol/g) and magnetic responsiveness of the adsorbent can greatly promote adsorption capacity and removal efficiency. The adsorbent also showed promising regeneration performance, and the adsorption capacity remained above 96% after six cycles.