Electron Transfer Reactions of Tetrakis (2, 2- Bipyridine)-µ Oxodiiron(III) Complex and Dithionate Ion in Aqueous Acidic Media: Kinetic and Mechanistic Approach

Communication in Physical Sciences, 2023, 10(1): 57-66 Authors: Atim Sunday Johnson, Idongesit Bassey Anweting* and Idongesit Edem Okon Received: 18 July 2023/Accepted 20 September 2023 Electron transfer reaction of tetrakis(2,2’- bipyridine)-µ-oxodiiron(III) complex (Fe2O4+) and  dithionate  (S2O62- )  has been carried out in aqueous hydrochloric acid. The reaction was carried out at [H+] = 1.0  × 10-3  mol dm-3, I = .3.0 × 10-1   mol dm-3(NaCl), T= 26 ± 1°C, and  λmax = 520nm. The stoichiometric ratio of the reaction is 1:1.The reaction is first order with respect to [Fe2O4+] and zero-order on [S2O62-] and is not hydrogen ion and ionic strength dependent. Added anions and cations do not affect the reaction, there was no gel formation upon the addition of acrylamide and excess methanol to the reaction mixture, which shows the absence of polymerisation, The products of the reaction were identified as Fe2+ and SO42-.  With recourse to empirical data, the reaction is rationalised to occur via an outer sphere pathway with ion pair character. A Plausible mechanism has been proposed for the reaction

Green Synthesis and Characterization of Iron Oxide Nanoparticles using Prosopis Africana Leaf Extract

Communication in Physical Sciences, 2023, 9(2):125-136 Authors: Patricia Adamma Ekwumemgbo*, Gideon Adamu Shallangwa, Idongesit Edem Okon and Ibe Awodi Received: 19 February 2023/Accepted 22 June 2023 Green synthesis of metal oxide nanoparticles has several advantages that include environmental friendliness. Arising on the usefulness of iron oxide nanoparticles (FeNPs) in several research and industrial quarters, we are reporting our current research outputs on the green synthesis of iron oxide nanoparticles (Fe3O4-NPs) from Prosopis Africana leaf extract. The synthesized Fe3O4-NPs were characterized by UV-vis spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET)/Barrett-Joyner-Halenda (BJH) analysis. The FTIR spectroscopy confirms the presence of phytochemicals in the extract for the reduction of metal ions to nanoparticles. SEM micrograph shows that the synthesized nanoparticles are spherical with sizes ranging from 30 nm – 100 nm. BET/ BJH analysis shows that the synthesized nanoparticles are microporous with a specific surface area (46.6 m2/g), pore volume (0.022 cm3/g) and pore size (1.79 nm). The XRD pattern revealed the amorphous nature of the synthesized nanoparticles and the UV-vis spectrum showed a characteristic peak at 400 nm for Fe3O4 nanoparticles