Effect of Co(II) dopant on the removal of Methylene Blue by a dense copper terephthalate

In this research, for the first time, a series of Co(II) doped copper terephthalate (CoX-CuBDC, where X is doping percentage) were successfully synthesized via solvothermal method and were tested for dye removal application. The physical properties of CoX-CuBDC were studied by several techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. The incorporation of Co(II) dopant leads to isomorphic substitution of Cu(II) in the CuBDC framework with the maximum doping percentage of 22. Doping and parent MOFs which are non-porous were used for removal of Methylene Blue (MB) from aqueous solution. Adsorption capacity of Co22-CuBDC and CuBDC are 52 and 58 mg/g, respectively, both of which are higher than the adsorption capacity recorded from several high porosity MOFs. Adsorption kinetic studies indicate that adsorption process follows pseudo-second order model while the adsorption mechanism is dominated by electrostatic attraction. Overall, even though these materials show non-porous characteristic, it can be used effectively in wastewater treatment application.