Copper-doped ZIF-8 nanomaterials as an adsorbent for the efficient removal of As(V) from wastewater

Arsenic pollution is an international problem that must be urgently controlled. Therefore, this study is based on a one-pot precipitation method, in which copper ions were added to a zinc organic metal framework (ZIF-8) to partially replace the zinc ions and the obtained adsorbent (Cu-ZIF-8) used to effectively remove As(V) ions from water. The successful synthesis of the Cu-ZIF-8 adsorbent and its adsorption mechanisms were confirmed using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). In addition, the effects of pH (3-11), initial arsenic concentration (10-350 mg/L), and reaction time on the adsorption performance were also characterized. Our findings demonstrate that Cu-ZIF-8 had a high As(V) adsorption capacity of 238.11 mg/g, which was significantly higher than that of most adsorbents previously reported in the literature. Moreover, this material maintained >75% of its initial adsorption capacity after four adsorption-desorption cycles. The adsorption kinetics of Cu-ZIF-8 were accurately described using the pseudo-second-order kinetic model, whereas the adsorption isotherm was fitted using the Langmuir model. Collectively, our findings have demonstrated that doping organic metal frameworks with metal ions can substantially improve their adsorption performance without changing their structural properties. Therefore, Cu-ZIF-8 is a promising adsorption material for the treatment of As(V)-contaminated water.