Enhancement of mechanical property and absorption capability of hydrophobically associated polyacrylamide hydrogels by adding cellulose nanofiber

Hydrophobically associated (HA) hydrogels have attracted great concerns with their admirable properties, such as self-healing and shape memory. However, a few works have been devoted to apply HA hydrogels in practice, especially in wastewater treatment. This may be because of the non-ionic monomer composition and the poor mechanical properties after swelling. In this work, in order to improve the mechanical properties and absorption behavior of HA polyacrylamide (HPAM) hydrogel, hydrophobically associated polyacrylamide/cellulose nanofiber (HPAMF) composite hydrogels were prepared. It was found that by incorporating CNF (2 wt%), the tensile strength (0.276 MPa) was largely increased by 632% compared to HPAM hydrogels. The maximum Cu ion adsorption capacity of the HPAMF hydrogel (containing 2 wt% CNF) was 2.33 mmol g(-1), about 86% over the HPAM hydrogel. The HPAMF hydrogels with self-healing, excellent mechanical and adsorption properties can be promisingly served as reliable absorbents, consequently satisfying the needs of practical application of heavy metal treatment.