Green synthesis of ZIF-8 nanoparticles for the simultaneous removal of Cd (II) and Sb (III) from contaminated wastewater

Researching efficient and green methods for removing toxic heavy metals from contaminated environments is of paramount importance. In this study, ZIF-8 nanoparticles were successfully synthesized at ambient temperature and pressure using a non-toxic water solvent. The synthesized nanoparticles underwent characterization through Brunauer-Emmett-Teller (BET), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscope (FESEM) analysis, followed by their application in the simultaneous adsorption of Sb (III) and Cd (II) from aqueous solutions. The thermodynamic behavior and adsorption kinetics of the prepared nanosorbent were also investigated. The kinetic data for cadmium and antimony adsorption on ZIF-8 nanoparticles exhibited a good fit with a pseudo-second-order model. The impact of pH on the adsorption capacity of synthesized nanoparticles for metal removal was evaluated. At T= 15◦C and pH 6.0, the maximum adsorption capacity of ZIF-8 nanoparticles was obtained: 31.8 mg∙g^(-1) for Cd (II) and 87.68 mg∙g^(-1) for Sb (III). The higher removal percentage for Sb (III) compared to Cd (II) might be because the ionic radius of antimony is smaller compared to cadmium, and its electronegativity is higher. The results demonstrated that ZIF-8 nanoparticles prepared through a facile and green method have the potential to serve as suitable adsorbents for the simultaneous uptake of cadmium and antimony from the environment.