Chitosan-based composite film adsorbents reinforced with nanocellulose for removal of Cu(II) ion from wastewater: Preparation, characterization, and adsorption mechanism

Utilizing natural and renewable natural polysaccharides as substrates to fabricate films or spinning with high metal ion adsorption and retain their mechanical properties is essential but challenging for the treatment of polluted water systems. In this study, the adsorption film was prepared with excellent mechanical properties and adsorption properties by blending chitosan (CS), poly (vinyl pyrrolidone) (PVP), beta-cyclodextrin (beta-CD), and nanocellulose (NCC). Fourier transform infrared spectroscopy, X-ray diffraction analysis, and scanning electron microscopy were used to investigate the microstructure of the film. The effects of the NCC content, contact time, temperature, initial concentration, and pH on the adsorption of Cu(II) ion were investigated. X-ray photoelectron spectroscopy (XPS) was used to explore the adsorption mechanism. The results showed that a suitable content of NCC enhanced the tensile strength of the CS/PVP/beta-CD/NCC composite film and improved its adsorption capacity under acidic conditions. The adsorption kinetics followed the pseudo-second-order kinetic model and the equilibrium data could be better described by the Langmuir isotherm. The thermodynamic parameters indicated that the adsorption of the Cu(II) ion onto the CS/PVP/beta-CD/NCC film exhibited physical adsorption and spontaneous process. XPS analysis showed that the nitrogen-containing functional groups play an important role during the adsorption process. Therefore, applying this adsorbent to remove metal ions during wastewater treatment is promising.