Adsorptive removal of Chromium(III) from aqueous solution using functionalized MIL 53: Amine, Sulfonic, and Cyano groups
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Date
2025-08-29
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Department of Chemistry, Federal University Dutsin-Ma (FUDMA), Katsina State, Nigeria
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.