Environmentally dependent adsorption of 2,4-dichlorophenol on cellulose-chitosan self-assembled composites

With the increasing need for bio-based materials developed by environmentally friendly procedures, this work shows a green method to develop shape-controlled structures from cellulose dissolving pulp coated by chitosan. This material was then tested to adsorb a common and widespread pollutant, 2,4-dichlorophenol under different pH conditions (5.5 and 9). Herein it was noticed that the adsorption only occurred in acidic pH (5.5) where electrostatic interaction drove the adsorption, demonstrating the potential to tune the response under desired conditions only. The adsorption was successful in the hydrogel structure with an adsorption capacity of 905 ± 71 mg/g from a solution with 16.6 ppm; furthermore, adsorption was also possible with dried hydrogel structures, presenting a maximum of adsorption of 646 ± 50 mg/g in a similar 16.6 ppm solution. Finally, adsorbent regeneration was successfully tested for both, dry (rewetted) and never-dried states, showing improved adsorption after regeneration in the case of the never dried hydrogel structures.