Exploration of the adsorption performance and mechanism of zeolitic imidazolate framework-8@graphene oxide for Pb(II) and 1-naphthylamine from aqueous solution

A novel composite of zeolitic imidazolate framework grown on graphene oxide (ZIF-8@GO) was successfully prepared and used for the adsorption of Pb(II) and 1-naphthylamine from aqueous solutions. The effects of contact time, pH, ionic strength and temperature on the adsorption performance of ZIF-8@GO was investigated by batch experiments. Compared to the bare ZIF-8 and GO, the ZIF-8@GO exhibited a significant increase in the adsorption for Pb(II) and 1-naphthylamine. The maximum adsorption capacities of ZIF-8@GO towards Pb(II) and 1-naphthylamine reached 356.0 and 171.3 mg/g at 293 K, respectively. Besides, the basic physicochemical properties of ZIF-8@GO were characterized by Scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectroscopy tests. The results revealed that ZIF-8@GO had large specific surface area, abundant functional groups and active sites on the surface, which could promote the adsorption of ZIF-8@GO for pollutants. In addition, based on zeta potential and X-ray photoelectron spectroscopy analysis, the primary adsorption mechanisms between ZIF-8@GO and Pb(II) were the surface complexation and electrostatic attraction, and the π-π interactions mainly contributed to the adsorption of 1-naphthylamine. In conclusion, as a new composite, ZIF-8@GO provides a reference idea for the removal of heavy metal ions and organic pollutants from water system.