Synthesis and Characterization of Nitrogen Base Covalent Organic Framework for Environmental Application

Abstract

Covalent organic frameworks (COFs) are porous two-dimensional and threedimensional structures due to their large structural diversity, inherent porosity, and excellent stability has been acknowledged as an excellent and versatile platform for gas adsorption, gas, and energy storage, as the heterogenous catalyst, in optoelectronic devices, in chemical sensing, treatment of wastewater, pollutants detection and their removal, photoconductivity, biomedical applications and for dye adsorption. Several different dyes are used for different applications to overcome the environmental parameters suitable dye storage, dye release, and dye removal method is required. So our main objective was to figure a desirable COF of resplendent porosity and stability with a less heat-intensive method for dye application. These days, there has been a major sake given to the development of the nanocomposites by employing the nanoscale panorama in one of two constituents. To produce nanocomposites of amended structure and corporeal features, the maintenance of nanoparticles and agglomeration is necessary for technological application. In this sense, Iron and Iron oxide nanoparticles have been considered as an efficient material for dye removal but iron-based magnetic nanoparticles (such as Fe3O4 and γ-Fe2O) have very low stability in harsh conditions, and decomposition of material result in loss of their magnetic properties. In this study, the modification of COFs is done by the preparation of Ironbased magnetic COFs (Fe3O4@LZU-1) which also ensue the stabilization of magnetic nanoparticles. For the preparation of Fe3O4 @LZU-1, a very facile approach is utilized which shows excellent chemical stability. Synthesis of Fe3O4 and Fe3O4@LZU1 was confirmed by FTIR and XRD. In FTIR spectra of Fe3O4@LZU-1, C=N appears at 1622 cm-1 that confirms the condensation reaction between two selected monomers. In XRD all the characteristics peaks were observed in the sample of Fe3O4 NPs and Fe3O4@LZU-1 fitted well with the JCPDS database (Card no. 075-1609) indicating that the formation of shell on the surface of NPs does not cause any evident change in diffraction peaks. According to the previous studies in Fe3O4 NPs for achieving the superparamagnetism, the estimated particles size is considered to be below 20 nm, and here in our reported work particle size for both magnetic nanoparticles and COFx magnetic nanocomposite is 11.93 and 10.58 nm which shows high magnetization saturation COF-LZU1 showed the adsorption of MB dye in room conditions without any stirring. The highest value of adsorption percentage is observed for 10 ppm solution which is 88.7 % indicating the electrostatic good selectivity due to the electrostatic interactions. Graphical abstract for the synthesis of Fe3O4@LZU-1 COF nanocomposite