Adsorptive Removal of Lead(II) ions from Aqueous Solutions Using Functionalized MOF-5 with Pyridine-2,6-dicarboxylic Acid
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Date
2025-08-22
Journal Title
Journal ISSN
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Publisher
University of Nigeria, Nsuka
Abstract
Sulfonic acid, cyano and amine-functionalized MOF-5+ pyridine-2,6-dicarboxylic acid (PDC)
were synthesized by Solvothermal method and characterized by X-ray Diffraction (XRD),
Fourier Transform Infrared (FT-IR), and Scanning Electron Microscope (SEM) mapping
analysis to confirm the synthesis of Metal-organic frameworks (MOFs) structures. The results of
N2 adsorption/desorption isotherm data showed that the Brunauer-Emmett-Teller (BET) surface
area of the synthesized MOF-5+PDC sample was 85.98 m2/g. The adsorption behaviour for Pb(II)
ions revealed an excellent adsorption capacity of 42.5 – 57.25 mg/g, whereas the removal
efficiency was over 80 - 90.9% when the initial concentration of Pb(II) ions was as low as 0.066
ppm. Design of Experimental was carried-out using Box-Behnken Design (BBD) based
Response Surface Methodology (RSM) to optimize the adsorption reaction conditions at 10 –
100 mg/L for concentration, 4 – 10 for pH, and dosage of 0.01 – 0.05 g, in seventeen
experimental procedures to achieve maximum adsorbed yield of Pb(II) ions. The results were
within the range of 77.02 – 99.64 mg/g. The quadratic model was found to adequately predict the
test amount adsorbed with an R2 value of 0.9054. In addition, thermodynamic analysis revealed
that Pb(II) adsorption is a spontaneous endothermic process. Based on the data from the study,
these amine-functionalized MOFs are a promising adsorbent for the removal of Pb(II) ions from
contaminated water.