Highly efficient capture of benzothiophene with a novel water-resistant-bimetallic Cu-ZIF-8 material

A novel water-resistant and bimetallic metal organic frameworks (MOFs), Cu-ZIF-8, was successfully synthesized by a coordination synthesis method for the first time. The structure properties of obtained MOFs can be probed and confirmed with nitrogen adsorption-desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS), etc. In addition, the pore size can be convenient adjusted by doping amount of Zn(II) and Cu(II) that the body-centered cubic crystal lattice of the parent ZIF-8 framework is continuously maintained. The pseudo-second-order model can make a good description of the adsorption kinetics, while Langmuir model could well express the adsorption isotherms. The Cu-ZIF-8 exhibited a remarkable benzothiophene (BT) uptake capacity compared with those previously reported adsorbents in the literatures. Especially, the Cu-ZIF-8 displayed an outstanding stability in the presence of benzene, octane and water, maintaining more than 95% initial uptake capacity after recycling five times. The as-prepared Cu-ZIF-8 might be a hopeful material for BT capture toward deep desulfurization. Our findings explored a simple and powerful way to incorporate metal ions into the backbones of open framework materials without losing their properties.