Browsing by Author "Ameh, Alechine Emmanuel"

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    Box-behnken design optimization of photocatalytic performance of znwo4 nanoparticles multiple doped with selected metals
    (Elsevier B.V., 2025) Muya, Francis Ntumba; Ameh, Alechine Emmanuel; Abubakar, Hassana Ladio
    Box-Behnken Design Optimization of the photocatalytic activity of the synthesized Na@Mg@Ti@ZnWO4 nanocomposite at different mixing ratios for the degradation of malachite green in wastewater was investigated. The synthesized ZnWO4-based nanomaterials were characterized using different analytical techniques. Optical analysis demonstrated a reduction in the band gap energy from 4.68 eV for ZnWO4 to 2.08 eV for the doped ZnWO4. HRTEM/HRSEM images revealed the formation of well-defined nanocrystals with distinct lattice fringes, while EDX confirmed the homogeneous distribution of dopants (Na, Mg, and Ti) on ZnWO4. The XRD analysis showed that the incorporation of the dopant did not change the phase of ZnWO4. In ZnWO4, XPS revealed electron sharing between 3 s (Na and Mg) and 3d (Ti) dopants. The host and doped ZnWO4 surface areas increased from 24.74 m2/g to 156.93 m2/g. Compared to the SPCE/ZnWO4/Na/Mg/Ti electrode, cyclic voltammetry analysis confirmed strong conductive properties. Maximum removal of 99.93 % malachite green (MG) from wastewater was achieved using catalyst load (0.7 g) (ZnWO4@NaMgTi), contact time (35 min), and pH 12. Even after five repeated cycles, ZnWO4 nanocomposite doped with 1 % Na, 1 % Mg, and 1 % Ti exhibited superior photocatalytic behavior than other ZnWO4 nanoparticles. A toxicity test demonstrated that dyeing wastewater treated with ZnWO4@NaMgTi nanocomposites supported aquatic life (juvenile fish) better than untreated dyeing wastewater, standard water of fish farming, and water treated with ZnWO4 nanoparticles alone. The immobilization of ZnWO4 with the dopants contributed to the enhanced photocatalytic and electrochemical performance.
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    Green-synthesis of MgO and ZrO2 nanocomposites: physicochemical properties and antiplasmodial activity in a mouse model
    (Elsevier, 2025) Oselusi, Samson Olaitan; Ameh, Alechine Emmanuel; Daniel, Augustine Innalegwu
    Malaria remains a significant global health burden, particularly in Sub-Saharan Africa, where drug resistance necessitates novel therapeutic strategies. This study evaluates the antiplasmodial potential of green-synthesized magnesium oxide (MgO) and zirconium oxide (ZrO2) nanoparticles and their composite (Mg/ZrO2) using Eucalyptus camaldulensis leaf extract. MgO, ZrO2, and MgO/ZrO2 nanoparticles were synthesized and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), revealing crystalline structures with particle sizes ranging from 39 to 60 nm. Acute toxicity assessment in mice indicated an LD50 > 2000 mg/kg bodyweight, confirming their safety. In vivo antiplasmodial activity was assessed using Plasmodium berghei-infected mice, with treatment groups receiving 50, 100, and 200 mg/kg bodyweight each of the nanoparticles. In the suppressive test, MgO-NPs, ZrO2-NPs, and MgO/ZrO2-NPs exhibited dose-dependent parasite inhibition of 66.79%, 34.72%, and 41.02% respectively at 200 mg/kg bodyweight. The curative test further confirmed parasite clearance, with MgO-NPs demonstrating the highest efficacy. Nanoparticle treatment also improved survival time and maintained body weight compared to untreated controls. The observed antiplasmodial effects is attributed to enhanced cellular uptake, reactive oxygen species (ROS) generation, and disruption of parasite metabolic pathways. These findings highlight the potential of MgO, ZrO₂ and MgO/ZrO2 nanocomposites as promising candidates for antimalarial drug development, warranting further mechanistic studies and preclinical validation.
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    Multifunctional metal oxides synthesized via a solvo-hydrothermal process for photocatalytic degradation of organic dye and bacteria in wastewater
    (Elsevier B.V, 2025) Mouele, Emile Salomon Massima; Mukaba, Jean-Luc; Petrik, Leslie; Ameh, Alechine Emmanuel; Bladergroen, Bernard; Muya, Francis
    The persistent occurrence of textile industrial dyestuff in water bodies has continuously threatened aquatic life and public health, requiring effective remediation. This study explores the solvo-hydrothermal synthesis of Ag2O, Fe2O3, AgFe2O3, TiO2, Ag-TiO2, Fe-TiO2, and AgFe-TiO2 catalysts. Various techniques, including SEM-EDS, FTIR, XRD, BET, TGA, and XPS characterized the as-prepared metal oxide (MO) catalysts. The multi-functionality of the catalysts was assessed on the degradation of Congo red dye and the inhibition of gram-positive B. subtilis in simulated wastewater. SEM analysis shows that MOs mostly appeared in granular morphologies except for Fe₂O₃, which comprised elongated grains, and showed that both Ag and Fe were successfully doped into the TiO₂ framework. The XRD survey revealed that Fe₂O₃ and TiO₂ were abundant in hematite and anatase phases. The BET findings indicated that the MOs are fine mesoporous particles, with TiO₂ showing the highest surface area of 83 m²/g, followed by 63, 28.27, and 24.03 m²/g for AgFe-TiO₂, AgFe₂O₃, and Ag-TiO₂, respectively. The antibacterial assays showed that Ag-TiO₂ and AgFe₂O₃ inhibited 58 % and 64 % of B. subtilis, correspondingly. The highest removals 98 and 99.99 % of Congo red (CR) dye were achieved with AgFe₂O₃ and TiO₂ after 5 h of irradiation time. At optimum conditions, AgFe₂O₃ and TiO₂ performed well and reached complete degradation up to 3 cycles. The outcomes of this study show that the multifunctional metal oxides produced via the solvohydrothermal method are thermally stable and can effectively be used for the simultaneous degradation of organic dye and disinfection of bacterial-polluted water