Porous cellulose nanofiber (CNF)-based aerogel with the loading of zeolitic imidazolate frameworks-8 (ZIF-8) for Cu(II) removal from wastewater

A novel biobased porous aerogel was synthesized using physical mixing, freeze-drying, and in-situ growth methods. Zeolitic imidazolate frameworks-8 (ZIF-8) were grafted onto the surface of the CS/CNF solid composite to form a ZIF-8@CS/CNF aerogel. The structural characteristics and the adsorption potential of the ZIF-8@CS/CNF aerogel were investigated. It was found that the specific surface area of the ZIF-8@CS/CNF aerogel was 206 m2/g, and the water stability of the CNF aerogel was enhanced by incorporating the CS. Meanwhile, the adsorption isotherm and kinetics of the composite aerogel fit the pseudo-second-order kinetic model (R2 = 0.96) and the Langmuir isotherm model (R2 = 0.97) with the copper(II) oxide (Cu(II)) theoretical adsorption capacity of 245 mg/g, respectively. Furthermore, this aerogel, which combined metal-organic frameworks (MOFs) and CNF, was easy to fabricate and it was biodegradable. These characteristics suggest it has a broad potential for wastewater treatment.