Synthesis and Characterization of Al-Based Metal Organic Framework for Environmental Application

Abstract

Metal organic framework, also called porous co-ordination networks are highly advanced class of crystalline materials with high porosity. MOFs synthesis is influenced via various factors such as solvent, pH and temperature of the system and can be synthesized via various routes. MOFs functionalization can be carried out presynthetically or via post-synthetic mode while there are various methods for the activation of MOFs out of which thermal activation is immensely in practice. Synthesis of environment friendly and water stable MOFs is the need of the hour, to be used in environmental applications. Aluminium being the light metal with smaller ionic radius and higher charge makes hydrothermally stable MOFs; a distinguished feature fit to carry out environmental applications such as dye adsorption and heavy metal remediation. Among variously synthesized MOFs, MIL-96(Al) stands out significantly in terms of stability. Three different combinations of MOFs 1) CTAB Modified MIL- 96(Al) 2) CTAB-Fe3O4@MIL-96(Al) 3) Fe3O4@MIL-96(Al)/Ag-CTAB, are prepared using MIL-96(Al). These MOFs are characterized via FTIR at each step of their synthesis to confirm the synthesis. XRD has been carried out to confirm the crystallinity of the synthesized materials. MIL-96(Al) is a microcrystalline structure, as proved from 2Ө using XRD studies; characteristics peaks appearing at 9.2o and 11.2o. Average crystal size is determined to be 30.84nm for CTAB Modified MIL-96(Al), 30.95nm for CTAB-Fe3O4@MIL-96(Al) and 16.98nm for Fe3O4@MIL-96(Al)/Ag-CTAB. These synthesized MOFs have turned out be efficient adsorbent for dye removal such as methylene blue. Adsorption efficiencies of CTAB Modified MIL-96(Al), CTABFe3O4@MIL-96(Al) and Fe3O4@MIL-96(Al)/Ag-CTAB are found to be 71.16%, 83.04% and 63.28%, respectively. Further, presence of certain functional groups in these MOFs can be suggestive of their use to be explored in heavy metal remediation as well.