The effect of copper(II) salt precursor on physicochemical properties of HKUST-1 MOFs and their application as adsorbents of Cr(III) ions from aqueous solutions

In this work HKUST-1 was synthesized using 4 different copper(II) salts precursors to investigate their effect on the physicochemical properties of obtained metal-organic frameworks (MOFs). To allow greener synthesis of HKUST-1, N,N-dimethylformamide-free (DMF-free) procedure was employed. Copper nitrate, copper sulphate, copper acetate, and copper chloride were selected for the syntheses. The yield of obtained products changed in order acetate>nitrate>sulfate, whereas synthesis with copper chloride yielded no product after 24 h at 110 °C hydrothermal treatment. The obtained materials were characterized by means of XRD, N2 adsorption−desorption at 77 K, TG, SEM, FTIR, DLS, and XPS. MOFs were further investigated as adsorbents of Cr(III) ions from aqueous solutions. Adsorption kinetics and adsorption statics models were correlated with the experimental data to gain a better understanding of the adsorption effectiveness.