Removal of Cu (II) from aqueous solutions using ZIF-8@GO composites

ZIF-8@GO-X (X = 0, 2.48%, 4.07%, 7.83%, and 20.03%) composites were prepared using GO and ZIF-8. The composites were used to absorb Cu(II) from aqueous solutions. With increasing GO content, the adsorption of the ZIF-8@GO-X composites first increased and then decreased. The Cu(II) adsorption of ZIF-8@GO-7.83% reaches a maximum among ZIF-8@GO-X composites (X = 0, 2.48%, 4.07%, 7.83%, and 20.03%). The adsorption kinetics, adsorption isotherm, adsorption thermodynamics, and adsorption mechanism of Cu (II) by ZIF-8@GO-7.83% were studied in this paper. The results showed that the adsorption reached equilibrium at 120 min, and ZIF8@GO-7.83% approached equilibrium relatively quickly. When the temperature was 45 degrees C and the Cu(II) concentration was 40 mg/L, the maximum adsorption capacity of ZIF-8@GO-7.83% for Cu(II) reached 482.29 mg/g. The equilibrium data and kinetics were well described by Langmuir and pseudo-first-order models, respectively. Final experiments with real factory wastewater (initial Cu(II) concentration of 670 mg/L) revealed that 0.37 g/L ZIF-8@GO-7.83% can efficiently redu ce the Cu(II) concentration to below 2 mg/L.

Automated summary

In this study, ZIF-8@GO-X (X = 0, 2.48%, 4.07%, 7.83%, and 20.03%) composites were prepared and used for Cu(II) adsorption. Among the composites, ZIF-8@GO-7.83% showed the highest Cu(II) adsorption capacity. The adsorption process was well described by Langmuir and pseudo-first-order models.