Preparation and Adsorption Performance of Heavy Metal Ions of a Complex Hydrogel of Oxidized Nanofibrillated Cellulose/Cationic Guar Gum

Nanocellulose, a rich source of natural biomass materials, has dual characteristics of green and environmentally friendly performance and nanomaterials. It presents some potential applications in the field of heavy metal pollution control in water systems. In this study, oxidized nanofibrillated cellulose (ONFC) was prepared by oxidation of nanofibrillated cellulose (NFC) with sodium periodate. ONFC was compounded with cationic guar gum (CGG) to prepare ONFC/CGG complex hydrogel. To evaluate the adsorption performance on heavy metal ions, Cu2+ was selected to evaluate the adsorption performance. The results showed that the appropriate pH range of the solution system was 3.5–6. As the pH of the solution increased, the ionization of the complex aerogel enhanced the electrostatic attraction between the cations and the aerogel surface, resulting in greater adsorption. With the constant increase of intital concentration, the maximum absorption capacity of ONFC/CGG hydrogel for Cu2+was also constantly increasing. When the intital concentration of Cu2+ reached 120 mg/L, the maximum adsorption capacity of the hydrogel for Cu2+ ions tended to be saturated. It demonstrates that ONFC/CGG hydrogel had a high adsorption efficiency for Cu2+. When the sorption time was 4 min, the adsorption became saturated, and the maximum adsorption capacity could reach 452.3 mg/g. This study has shown that ONFC/CGG hydrogel has a wide range of raw material sources and low cost. When absorbing heavy metal ions by the hydrogels, the pH value has a wide range. Meantimes, the adsorption efficiency is high. It has wide application prospects in the field of heavy metal pollution control in water systems.