Functionalized copper metal-organic framework with peroxidase-mimetic activity as an adsorbent for efficient removal of noxious organic dye from aqueous solution

We show that Cu-BDC-NH2 could be employed as a peroxidase-mimetic catalyst for Fenton-like degradation of methylene blue (MB) in water. The three-dimensional copper-based MOF was constructed solvothermally by dissolving CuCl2.2H2O and 2-amine-1, 4-benzenedicarboxylic acid (1, 4-BDC-NH2) in DMF. Transmission electron microscopy, Fourier transform infrared spectroscopy, Powder X-ray diffraction, the Brunauer–Emmett–Teller technique, Thermal Gravimetric Analysis, X-ray Photoelectron Spectroscopy, UV–Vis, and fluorescence spectroscopy were used to characterize the material. The influence of pH, temperature and concentration dose of Cu-BDC-NH2 on MB degradation was examined. According to the results, not only does Cu-BDC-NH2 sustain a reasonably high level of activity at pH 3, but it also work efficiently in a neutral to basic pH range, showing good stability and endurance. Under ideal conditions, full removal of MB was accomplished in 60 min. The peroxidase activity provided an advantage in removing the dye in a short period of time. Selective adsorption of dyes over Cu-BDC-NH2 were also conducted by combining two cationic dyes. The elimination of MB was above 80% after four cycles, demonstrating the high recyclability. The results show that Cu-BDC-NH2 not only significantly adsorbs the dye but also exhibits photocatalytic activity. Because of their good activity in broader pH range, higher temperature endurance and greater recyclability for MB removal, the treatment technique may be simplified for practical use and thereby lowering treatment costs.