Ionic cross-linking of cellulose nanofibers: an approach to enhance mechanical stability for dynamic adsorption

Herein, we attempt to improve the mechanical stability of anionic functionalized cellulose nanofibers (a-CNF) having 1.25 mmol of carboxymethyl groups per gram of cellulose nanofibers (CNF). The a-CNF and cross-linked a-CNF (z_a-CNF) then used for water desalination in the continuous mode using a tubular adsorption column. It is worth mentioning that the z_a-CNF possess 40% degree of cross-linking provided better mechanical stability as the tensile strength improved from 3.2 to 5.2 MPa over a-CNF. The IR spectroscopy was used to confirm the success of chemical modifications. Upon ionic cross-linking, the BET surface area reduced from 13.53 to 7.54 m²·g^-1 corresponds to a-CNF and z_a-CNF, respectively. Moreover, this research was extended to determine the dynamic adsorption capacities for a-CNF and z_a-CNF, which were found to be 21 and 10 mg·g^-1 respectively at a flow rate of 5-mL·min^-1 explained by Thomas model.