Browsing by Author "Masuku, Makhosazana"

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    Microwave assisted synthesis of oleic acid modifed magnetite nanoparticles for benzene adsorption
    (Environmental Nanotechnology, Monitoring & Management, 2021-01-30) Masuku, Makhosazana; Ouma, Linda Immaculate; Pholosi, Agnes
    Benzene is a carcinogenic, mutagenic and highly toxic nonpolar organic compound, its presence in water occurs as a result of leakage of underground pipes and improper effluent disposal. Adsorption techniques have proven to be efficient for benzene removal from water providing a low maintenance method with high removal efficiencies. Nanoparticles provide high surface areas for adsorption and magnetite particles are specifically advantageous owing to their magnetic characteristics. Magnetite surfaces require modification with hydrophobic compounds for the adsorption of nonpolar pollutants. Herein, magnetite nanoparticles (MNP) were modified with oleic acid to form a magnetite-oleic acid composite (MNP-OA) via microwave synthesis for the adsorption of benzene from simulated wastewater. Infrared analysis confirmed the interaction between magnetite and oleic acid and particle diameters were determined by XRD analysis as 19.7 nm and 17.1 nm for MNP and MNP-OA respectively. Magnetic measurements indicated that both materials were superparamagnetic with a decrease in saturation magnetization after modification due to the non-magnetic layer on the surface. Oleic acid modification improved the benzene uptake of magnetite nanoparticles by approximately 30 % while kinetic studies suggested that a concentration driving force controlled the adsorption process. The adsorbent was regenerated and was efficient for five adsorption-desorption cycles.
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    Optimization studies of BTX removal by magnetite coated oleic acid obtained from microwave‑assisted synthesis using response surface methodology
    (Scientific Reports, 2022-12-13) Masuku, Makhosazana; Ouma, Linda; Sanni, Saheed; Pholosi, Agnes
    Benzene, toluene and xylene (BTX) are volatile organic compounds released into the environment, that require urgent removal to avoid adverse health effects. In this work, the modelling and optimization of the preparation factors for magnetite coated oleic acid (MNP-OA) composite from microwave synthesis using response surface methodology were conducted to maximize BTX removal, and iron content. The influence of five crucial preparation variables: the Fe3+/Fe2+ solution volumes, microwave power, volume of ammonia water (VAW), reaction time and volume of oleic acid (VOA) on the iron content (% Fe), and BTX adsorption capacity were investigated. The analysis of variance results revealed that VOA and VAW were the most influential factors for high % Fe content, and improved BTX removal. The % Fe, and BTX adsorption capacity for MNP-OA composite at optimized experimental conditions were estimated to be 85.57%, 90.02 mg/g (benzene), 90.07 mg/g (toluene), and 96.31 mg/g (xylene).