Optimization of Chitosan - MIL-101(Fe) - Polyethyleneimine MOF-Based Composite Beads for Methyl Orange Removal

Abstract

Metal-Organic Framework (MOF)-based composite beads consisting of MIL-101(Fe), Chitosan (CS), and Polyethyleneimine (PEI) crosslinked with glutaraldehyde (GLA) were synthesized. Response Surface Methodology was used to optimize the synthesis conditions of the beads to maximize Methyl Orange (MO) removal via batch adsorption experiments. Using an experimental design with three independent variables MIL-101(Fe) (500-1500 ppm), PEI (1-2%), GLA (0.5-2.5%), a second-order polynomial model was obtained to relate MO removal and these variables. A high R2 (0.9944) and F-value (176.97) suggested good agreement between experimental data and the model. The optimum beads were found to consist of 500 ppm MIL-101 (Fe), 1.44% PEI, crosslinked in 2.11% GLA corresponding to a percent MO removal of 95.75%. Validation experiments done by subjecting the optimized beads to batch adsorption of MO confirmed good predicting capability of the model with an experimental MO removal of 96.20%. Characterization of the beads was performed using Fourier Transform Infrared Spectroscopy (FTIR) analysis and Scanning Electron Microscope (SEM). The beads were found to contain multiple functional groups and have a coarse surface with a porous structure which are ideal attributes for good adsorbents.the beads was performed using Fourier Transform Infrared Spectroscopy (FTIR) analysis and Scanning Electron Microscope (SEM). The beads were found to contain multiple functional groups and have a coarse surface with a porous structure which are ideal attributes for good adsorbents.