Porous Cu-based metal organic framework (Cu-MOF) for highly selective adsorption of organic pollutants

In this study, copper based metal organic frame work (Cu-MOF) was synthesized by using different solvents i. e. H 2 O, Dimethylformamide (DMF) and DMF ​+ ​C 2 H 5 OH ​+ ​H 2 O solutions at various temperatures. Cu-MOF synthesized in different solvents exhibited a large number of properties and advantages including easy synthesis procedure, high porosity, good crystallinity , high surface area, massive pore volume , controllable pore surface properties (zeta potential), rigid and chemical stability. The as-synthesized Cu- MOF was analysed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area, zeta potential , electrostatic attraction and Thermal gravimetric analysis (TGA). A higher BET surface area of 121.1 ​m 2  ​g −1 was obtained for Cu-MOF synthesized in DMF ​+ ​C 2 H 5 OH ​+ ​H 2 O compared with H 2 O (109.3 ​m 2  ​g −1 ) and DMF (115.1 ​m 2  ​g −1 ) solvents. The as-obtained Cu-MOF was used to investigate adsorption kinetic performances of methylene blue (MB) and methyl orange (MO) dye molecules. Compared with other samples, Cu-MOF synthesized in (DMF ​+ ​C 2 H 5 OH ​+ ​H 2 O) has a significantly enhanced adsorption ability for MB but a lower for MO dyes. After 4 ​min, the adsorption co-efficient ( k) values were calculated to be 0.506, 0.846 and 1.1915 min −1 for MB and 0.029, 0.024 and 0.005 min −1 for MO dyes for Cu-MOF (H 2 O), Cu-MOF (DMF) and Cu-MOF (DMF ​+ ​C 2 H 5 OH ​+ ​H 2 O), respectively. It was found that Cu-MOF has a higher adsorption for MB dye but a poor adsorption capacity for MO, which was attributed to the electrostatic attraction/repulsion phenomena. Moreover, compared with Cu-MOF (DMF) and Cu-MOF (H 2 O), Cu-MOF (DMF ​+ ​C 2 H 5 OH ​+ ​H 2 O) shows an improved stability at 370, 417 and 423 ​°C temperatures. The result obtained through experiment suggested that porous Cu-MOF microstructures synthesized in DMF ​+ ​C 2 H 5 OH ​+ ​H 2 O have potential application for the treatment wastewaters having MB and MO dyes.