Browsing by Author "Awokoya KN"

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    Nanocrystalline cellulose derived from melon seed shell (Citrullus colocynthis L.) for reduction and stabilization of silver nanoparticles: Synthesis and catalytic activity
    (2021) Ogundare SA; Moodley V; Amaku JF; Ogunmoye AO; Atewolara-Odule OC; Olubomehin OO; Awokoya KN; Sanyaolu NO; Ibikunle AA; van Zyl WE
    Melon seed shells (MSS) are a hazard to the environment as they host disease vectors. To alleviate the effect, we explored melon seed shells (MSS) as a new source of nanocrystalline cellulose (NCC) with reducing- and stabilizing capacity for the synthesis of silver nanoparticles (AgNPs). The isolation of NCC from discarded MSS served the dual purpose of a reducing- and stabilizing agent in the synthesis of AgNPs. The isolated needle-like crystals (MSS-NCC) had a mean length 204 nm, width 7 nm and aspect ratio 30. The NCC had crystallinity index of 94% with surface rich in –OH and –COOH functionality. The obtained AgNPs covered the surface of the MSS-NCC and catalysed the reduction of nitrobenzene to aniline using NaBH4. The process of the reduction monitored via UV-vis spectroscopy was completed within 12 min. with a rate constant 0.04 min−1 as revealed by the kinetic study.
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    Preparation, characterization and evaluation of a styrene-based molecularly imprinted polymer for capturing pyridine and pyrrole from crude oil
    (2021) Awokoya KN; Okoya AA; Elujulo O
    The rapid increase in global energy demand met with fossil fuel exploration and use as an energy source has not been achieved without its impacts on human and environmental health. Consequently, the imposition of stricter measures on key pollution sources in the effort to reduce the emission of contaminants into the environment became necessary. In this work, a new molecularly imprinted polymer (MIP) targeting pyridine (pyd) and pyrrole (pyr) was synthesized using styrene as a functional monomer. MIP and the non-imprinted polymer (NIP) were characterized by infrared spectroscopy, x-ray spectroscopy, and scanning electron microscopy. The polymer had spongy surfaces and porous network structures. The effects of several factors, such as initial analyte concentration, contact time, and adsorbent dose on pyd and pyr removal efficiencies from crude oil were evaluated. Quantitative analyses indicated that the removal of pyd and pyr occurred at fast kinetics, with a removal efficiency of 15.12 and 15.33, respectively, after 10 min of adsorption time. Optimum adsorption for both analytes was however not reached until 420 min, indicating slow kinetics. The uptake of the analytes increased with a rise in concentration. The highest removal percentages were recorded at 99.9% and 99.7% for pyd and pyr respectively, at 0.06 mol dm−3 adsorbate concentration of the modeling organic media. Two adsorption isotherm models were applied to analyze the equilibrium data, obtaining the best description by the Freundlich isotherm model. The accuracy of the MIP materials was validated using Bonny crude oil from Nigeria. The results showed that the MIP was effective for the adsorption of pyd and pyr in both modeling organic media and real crude oil.