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Browsing Articles by Author "Gitari, Mugera W."

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    Biosynthesis of Ultrasonically Modified Ag-MgO Nanocomposite and Its Potential for Antimicrobial Activity
    (Hindawi, 2018-08-29) Ayinde, Wasiu B; Gitari, Mugera W.; Muchindu, Munkombwe; Samie, Amidou
    This study reports a green synthesis route for a bilayered Ag-MgO nanocomposite using aqueous peel extract of Citrus paradisi (grapefruit red) under an accelerated uniform heating technique and its antibacterial potency against Escherichia coli. Surface modifications and composition of the nanocomposite were examined using a UV-visible spectrophotometer, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray (EDX) analyzer. (e efficiencies of the as-synthesized Ag-MgO nanocomposite against Escherichia coli were examined. (e synthesized Ag-MgO nanocomposite showed characteristic synergetic bands at 290nm for MgO nanoparticle and at around 440nm for Ag nanoparticle which blue-shifted to 380nm in the composite. A spherically dispersed nanocomposite with cubical crystal lattice network with a diameter of about 20–100nm comprising Ag nanoparticle embedded within MgO nanoparticles was obtained. (e nanocomposite produced stronger antibacterial activity against Escherichia coli as compared to MgO nanoparticle, indicating a higher interaction between Ag and MgO ions. (e nanocomposite was successfully synthesized via an efficient modified method by bioreductive agents with an improved synergistic antibacterial property towards water purification.
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    Mineralogical and Chemical Characteristics of Raw and Modified Clays and Their Application in Arsenic and Fluoride Removal: Review
    (IntechOpen, 2018-11-05) Gitari, Mugera W.; Mudzielwana, Rabelani
    Clay and clay minerals have always been used since the ancient times for making ceramic materials and also as a building material. Over the past decades, there has been a growing trend in their applicability in different areas such as industries, environmental remediation and water treatment sectors. The growing trend is mainly associated with the fact that they are chemically and mechanically stable, have higher specific surface area and cation exchange capacity. Furthermore, clays can be modified to improve their functionalities in different sectors. In this chapter, we present a review of the structural, mineralogical and chemical properties of clay and the effect of surface modification in their structures. We further looked at their applicability in arsenic and fluoride removal in their raw and also in their modified form. Although the literature showed that modified clay minerals yields higher adsorption capacity as compared to raw clays little nothing has been reported yet in relation to the cost of modifying clays with chemical species. As such new studies should also elaborate on the cost effectiveness of modifying clay minerals with chemical species.