Room temperature synthesis of copper-modified ZIF-8/Chitosan for enhanced adsorptive removal of congo red

Abstract

The synthesis of Cu(II)-doped ZIF-8/Chitosan by means of the one-pot method at room temperature was successfully carried out. The synthesized materials exhibit enhanced adsorption properties for the removal of Congo red (CR) dye. The structural and morphological properties of Cu(II)-doped ZIF-8/Chitosan were characterized. Cu(II)-doped ZIF-8/Chitosan achieved the most optimal CR removal efficiency and CR adsorption capacity (153.85 mg/g) due to its higher specific surface area (522.776 m2/g) compared to ZIF-8/Chitosan (514.882 m2/g). Electrostatic attraction, hydrogen bonding, and π-π interaction are the main interactions for the higher adsorption performance. The CR adsorption process followed pseudo-second-order kinetic model and Langmuir isotherm model. The results of the thermodynamic adsorption indicated that the process of CR adsorption by Cu-doped ZIF-8/Chitosan was an endothermic reaction. The experimental results indicate that the Cu(II)-doped ZIF-8/Chitosan material has the potential to be used in wastewater treatment for the removal of anionic dyes.