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- ItemAdsorptive removal of Chromium(III) from aqueous solution using functionalized MIL 53: Amine, Sulfonic, and Cyano groups(Department of Chemistry, Federal University Dutsin-Ma (FUDMA), Katsina State, Nigeria, 2025-08-29) Ogundele, D. T., Adeyemi, D. A., Olayemi V. T., Mustapha A. O and Jimoh A. AMetal-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.
- ItemSensitive Detection of Dichlorvos Pesticide in Aqueous Phase using a Cobalt(II) Coordination Polymer based on Biphenyl-4-carboxylic acid(Faculty of Science, Federal University Birnin Kebbi, 2025) Olayemi, V. T., David, A. C., Kamorudeen, A. A., Ofuje, A. A., Abedoh J. O and Jaji, B. AA cobalt-based coordination polymer (CP), [Co(Biphen)2(Tmp)2]n.(H2O), was successfully synthesised and characterised using Fourier-Transform Infrared Spectroscopy (FTIR), ultraviolet visible spectroscopy (UV-Vis), Thermogravimetric analysis (TGA), and Scanning Electron Microscopy (SEM). The MOF appeared as a blue crystalline solid with a melting point of 257 °C and a molecular weight of 889.92 g/mol. It was slightly soluble in Dimethy sulphoxide (DMSO) but insoluble in ethanol, methanol, n-hexane, Dimethylformamide (DMF), and water. FTIR analysis revealed shifts in the C=O band from 1684 cm-1 in the free Biphen ligand to 1681 cm⁻1 in the complex, as well as the appearance of carboxylate (COO-) symmetric and asymmetric stretching bands at 1608 cm-1 and 1535 cm-1, respectively, with a Δν value of 73 cm-1, confirming a chelating bidentate coordination mode. Additional Co-O and Co-N stretching bands appeared at 516 and 621 cm-1, respectively. UV-Vis spectra exhibited ligand-based π→π*/ n→π* transitions and d-d transitions characteristic of octahedral Co(II) centers. TGA revealed three decomposition stages with high thermal stability. SEM analysis revealed aggregated, porous micro- to nanosized particles with a cauliflower-like morphology. The compound showed a distinct emission band at 630 nm upon excitation at 318 nm. This was attributed to ligand to metal charge transfer (LMCT) because of cheating the metal to the ligand. The compound also showed high selectivity towards dichlorvos pesticide among other organic compounds tested via luminescence sensing.
- ItemGreen-route synthesis of coordination polymers using terephthalic acid from plastic wastes for the removal of endocrine-disrupting chemical (Atrazine) from aqueous solution(Springer, 2025) Tella, A. C., Ugwuanyi, U. V., Olayemi, V. T., Adeyemi, O. G., Clayton, H. S., Fapojuwo, D. P., Olawale, M. D., Adimula, V. O and Owalude, S. OTerephthalic acid (TPA) was successfully extracted from polyethylene terephthalate (PET) plastic bottles through alkaline hydrolysis. Coordination Polymers ([Zn(TPA)2(H2O)2], and [Co(TPA)2(H2O)2]), and [Ni(TPA)2(H2O)2] (TPA = Terepthalic acid) were synthesized by grinding terepthalic acid extracted from the plastic waste with metal acetate salt via green synthetic method (ball-milling). These were characterised using FTIR, PXRD, BET, Melting Point analysis, UV–Vis spectroscopy, XRF and SEM techniques to investigate the functional groups, structural crystallinity, surface area, thermal stability, electronic transition, elemental composition and morphology of the material, respectively. Adsorption studies for the removal of endocrine-disrupting chemicals (Atrazine) were carried out to understand their applicability in the removal of pesticide residues from a polluted environment. The study also shows that the synthesized coordination polymers were favorable for Atrazine removal, for which [Co(TPA)2(H2O)2], [Ni(TPA)2(H2O)2], and [Zn(TPA)2(H2O)2] showed a maximum adsorption capacity of 41.322, 52.91 and 60.241 mg/g, respectively. The kinetics study shows that Atrazine adsorption followed a pseudofirst- order kinetics model. The thermodynamic parameters were calculated, and the results showed that the adsorption of Atrazine on the coordination polymers is a spontaneous and exothermic process. Therefore, all the synthesised coordination polymers are promising adsorbents for the removal of Atrazine pesticide in a polluted environment.
- ItemSynthesis and luminescent properties of transition metal coordination polymers of multidentate carboxylate and N-donor ligands(Nigerian Research Journal of Chemical Sciences, 2025-09-28) Olayemi, V. T., David, A. C., Olanipekun, B. E., Ogundele, D. T., Abedoh J. O and Jaji, B. A
- ItemA fluorescent copper(II) complex based on 4,4-oxybisbenzoic acid and benzimidazole for selective detection of nitroaromatic compounds(Nigerian Society of Physical Sciences, 2026) Olayemi, V. T., Oladipo, A. C., Adimula, V. O., David, A. C., Abedoh, J. O., Jaji, B. A and Tella, A. CNitroaromatic compounds (NACs) are electron-deficient aromatic molecules extensively used in explosives, dyes, and pesticides, and their high toxicity and environmental persistence pose serious risks to human health and ecological systems. Consequently, the development of sensitive, selective, and portable sensing platforms for NAC detection is of significant importance. In this work, a copper-based coordination complex, [Cu(Oba)2(Beim)(H2O)] (1) (H2Oba = 4,4’-oxybisbenzoic acid; Beim = benzimidazole), was synthesized via a conventional method and fully characterized using standard instrumental techniques. Infrared spectroscopy confirmed the coordination environment, with characteristic bands observed at 1666 cm−1 (νC = O), 1243 cm−1 (νC − N), and 3061 cm−1 (νN − H). The complex exhibits strong fluorescence emission at 490 nm and good thermal stability. Fluorescence sensing studies revealed a significant quenching response in the presence of NACs, particularly 4-nitroaniline. The sensor demonstrated a low limit of detection (LOD) of 1.46 ppm and a high Stern–Volmer quenching constant (KSV = 9.16 × 104 M−1) towards 4-nitroaniline, indicating excellent sensitivity and selectivity. Furthermore, recyclability experiments showed that the complex could be reused for up to four sensing cycles without significant loss of performance. These results highlight the potential of the copper coordination complex as an efficient and reusable fluorescent sensor for nitroaromatic compounds.