Synthesis, Characterization, and Application of ZIF-67 Metal-Organic Framework to Enhance the Microstructure and Compressive Strength of Cement Composite

Abstract

Metal-organic frameworks (MOFs) are beneficial in various applications such as gas separation, catalysis, wastewater treatment, and dye removal. The current study proposes a novel approach to the use of the zeolitic imidazolate framework (ZIF-67), a subfamily of MOFs, in cement composites. ZIF-67 nanoparticles were synthesized in the laboratory and analyzed using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscope (TEM). ZIF-67 nanocrystals were incorporated in the cement matrix at a concentration of 0.3%, 0.4%, 0.5%, and 0.6% by weight of cement. The influence of ZIF-67 nanoparticles on the workability, mechanical strength, and microstructure was thoroughly investigated. The workability of cement paste was hindered by the addition of ZIF-67. The compressive strength of ZIF-67 cement composites was enhanced by 27.81% at 3 days and 20.36% at 28 days. This was attributed to the densification of microstructure. The optimum content of ZIF-67 in cement composites among the selected concentrations was determined to be 0.6% by weight of cement. The microstructure images revealed the pore-filling mechanism of ZIF-67 in cement composition as well as in providing additional nuclei sites for the hydration products. It was concluded that ZIF-67 nanoparticles act as a nonreactive filler in cement composites. There exists a huge potential for use of ZIFs in cement composites, which is yet to be explored.