Adsorptive Removal of Chromium (III) From Aqueous Solution Using Funtionalized MIL53: Amine, Sulfonic, and Cyano groups

Abstract

Metal-organic frameworks (MOFs) based on 1,4-benzenedicarboxylic acid Were synthesized and modified via post-synthetic modification, incorporating sulfonic, cyano, and amino functional groups. Various techniques, including Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS), thermogravimetric analysis and differential thermal analysis (TGA-DTA), and Brunauer-Emmett-Teller (BET), used to assess the functional group, structures, surface area, thermal stability, and pore characteristics. The results confirmed successful incorporation of SO2H, CN, and NH2 functional groups into the MOFs. The adsorption capacities of the MOFs show that MIL-53+CN adsorbent has the highest adsorption capacity (qe values) of 59 mg/g, followed by MIL-53+SO2H (55.75) mg/g, while MIL-53+NH2 adsorbent has the lowest adsorption capacity of 49 mg/g. Thermodynamic analysis indicated an exothermic adsorption process. Also, Response surface methodology (RSM) with Box-Behnken Design (BBD) was used to optimize adsorption conditions, including concentration (10-100 mg/L), pH (4-10), and dosage (0.01-0.05 g). The model predicted maximum adsorption yields for MIL-53+SO3H, MIL-53+CN and MIL-53+NH2, with values of 96, 79 and 92.06 mg/g, respectively, under specific conditions. The results demonstrate the potential of functionalized MOFs, particularly MIL-53+SO3, for the selective removal of Cr(III) metal ions from aqueous media