Synthesis of ZIF-8@GO-COOH and its adsorption for Cu(II) and Pb(II) from water: Capability and mechanism

Abstract

The removal of heavy metal ions from the aqueous environment is an important topic as heavy metal pollution is widely distributed in water bodies, causing serious damage to aquatic ecosystems and worsening the already scarce freshwater resources. In this work, we report the synthesis of novel ZIF-8@GO-COOH composite nanosorbent materials by in situ self-assembly. The physicochemical properties of the composites were investigated using relevant characterisation techniques, and the adsorption capacity of ZIF-8@GO-COOH for copper and lead ions in aqueous solution was tested by batch adsorption experiments. The adsorption behaviour was analysed by combining adsorption kinetics, adsorption isotherm model and Van't Hoff model. The results showed that the adsorption capacities of ZIF-8@GO-COOH for Cu(II) and Pb(II) were 93.26 mg/g and 95.875 mg/g, respectively, when the initial heavy metal ion concentration was 100 mg/L, the adsorption time was 60 min, the temperature was 293 K and the pH conditions were suitable. The high adsorption performance of ZIF-8@GO-COOH was attributed to its surface with abundant oxygen-containing functional groups and excellent specific surface area, which gives it a significant advantage in the removal of heavy metal ions from aqueous solutions.