Solvent-Free Mechanochemical Preparation of Metal-Organic Framework ZIF-67 Impregnated by Pt Nanoparticles for Water Purification

In this study, the crystalline metal-organic framework (MOF) ZIF-67 was obtained using the solvent-free ball milling method, which is a fast, simple, and economical green method without the need to use solvents. Using the impregnation method, platinum metal ions were loaded in the MOF cavities. Various descriptive methods have been used to explain the prepared Pt@ZIF-67 compound, such as FTIR, BET, TEM, SEM, EDS, XRD, TGA, and ICP. Based on this, the results showed that Pt nanoparticles (0.26 atom%) were located inside the pores of ZIF-67. In addition, no evidence supports their accumulation on the MOF surface. The efficiency of Pt@ZIF-67 was approved in the reduction of toxic and harmful nitrophenol compounds in water. The results showed that the removal of 4-nitrophenol in aqueous medium was successfully achieved with 94.5% conversion in an optimal time of 5 min with the use of NaBH4, and catalyzed by Pt@ZIF-67. Additionally, the Pt@ZIF-67 was recoverable and successfully tested for five qtr runs, with reasonable efficiency.