One new hexatungstate-based binuclear nickel(II) complex with high selectivity adsorption for organic dyes

A new hexatungstate compound, [Ni2(L)3]2[W6O19]·2H2O (1) (HL = 2-acetylpyrazine-N(4)-methyl thiosemicarbazone) has been synthesized and characterized by elemental analyses, infrared (IR) spectroscopy, thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), single-crystal X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and UV–Vis spectra. A 3D supramolecular structure of 1 is formed by hydrogen bonding, which exhibits a highly selective adsorption for methylene blue (MB), gentian violet (GV) and fuchsin basic (FB) organic dyes with the efficiencies of 99%, 94% and 94%, respectively. Additionally, the adsorption kinetics demonstrates that the MB removal corresponds to the pseudo-second-order model. The recyclability experiments illustrated that 1 could be reused at least five cycles, revealing a potential ability in the disposal to dye wastewater.