Browsing by Author "Masikane, Siphamandla C"

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    Cashew nut shell: a potential bio-resource for the production of bio-sourced chemicals
    (Green Chemistry, 2019) Mgaya, James; Shombe, Ginena B; Masikane, Siphamandla C; Mlowe, Sixberth; Mubofu, Egid B; Revaprasadu, Neerish
    Exploitation of agricultural waste as green starting materials to produce various valuable products is attracting the attention of academic, industrial and other practitioners. Cashew nut shell (CNS) and its liquid extract (CNSL) in particular have been identified as agro-wastes rich in valuable and functional renewable products. The unique structural features of the CNSL constituents offer the possibility for different modifications to suit various applications. This review article provides recent developments in CNS and CNSL as green sources for use in the production of biorenewable chemicals, materials and energy. Extraction methods and applications of CNS, CNSL and isolates are discussed. Furthermore, a literature survey of the current status and efforts made on the utilization of these agricultural and food wastes for different applications is well outlined.
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    Castor Oil Production and Applications
    (Nova Science Publishers, 2018) Mlowe, Sixberth; Masikane, Siphamandla C; Kyobe, Joseph W; Mubofu, Egid B; Revaprasadu, Neerish
    Castor oil extracted from the castor oil seeds of Ricinus communis is an important naturally occurring oil identified as a useful raw material for diverse industrial applications. Historically, the oil has been used in medicinal fields (as a laxative agent) as well as in cosmetics. The main attractive attributes of this oil include biodegradability and non-volatility. Thus, this has recently enabled derivatization to afford value-added chemicals through alternative green synthetic protocols. The oil contains a large percentage of an unusual fatty acid, 12-hydroxy-9-cisoctadecenoic acid, commonly known as ricinoleic acid. Ricinoleic acid can be easily extracted through chemical processes and subsequently exploited as a biosource for the production of high-grade lubricants, transparent typewriter and printing inks, textile dyes, leather preservation agents and polyamide nylon-type fibres. The most recent advances identify castor oil and its major isolate (ricinoleic acid) as potential green solvents and/or capping agents in the synthesis of high quality nanomaterials and nanocomposites.
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    Lead(II) halide cinnamaldehyde thiosemicarbazone complexes as single source precursors for oleylamine-capped lead sulfide nanoparticles
    (Journal of Materials Science: Materials in Electronics, 2018) Masikane, Siphamandla C; Mlowe, Sixberth; Gervas, Charles; Revaprasadu, Neerish; Pawar, Amol S; Garje, Shivram S
    Different PbX2 (X = AcO, Cl, Br, I) metal salts were complexed to cinnamaldehyde thiosemicarbazone ligand. The resulting complexes were characterised using Fourier Transform Infrared spectroscopy, 1H and 13C {1H} Nuclear Magnetic Resonance spectroscopy, elemental analysis and thermogravimetric analysis techniques. They were then used as single source precursors for the preparation of lead sulfide (PbS) nanoparticles using the colloidal thermolysis route where oleylamine is used as the passivating agent. Each SSP is thermolysed at reaction temperatures of 190, 230 and 270 °C. Predominantly cubic-shaped PbS nanoparticles were obtained, with an exception of the truncated nanocubes obtained from thermolysis of the SSP prepared from lead bromide. Varying particle sizes are obtained when the halogen is varied, ranging from ca. 50 to 400 nm. The optical absorbance of the PbS nanoparticles in the UV-Vis- NIR range was found to be blue-shifted when compared to bulk PbS.
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    Progress in Green Solvents for the Stabilisation of Nanomaterials: Imidazolium Based Ionic Liquids
    (IntechOpen., 2018) Tshemese, Zikhona; Masikane, Siphamandla C; Mlowe, Sixberth; Revaprasadu, Neerish
    For over a decade, ionic liquids (ILs) have attracted enormous attention from scientists across the globe. The history of these compounds traces back to 1914 where the inception of the first IL with a melting point of 12°C was made. Years later, a progression of the remarkable related compounds have been discovered. Out of many analogous compounds realized from time to time, the imidazolium class of ionic liquid is the most studied because of their air and moisture stability. The physicochemical properties of ILs differ significantly depending on the anionic/cationic species and alkyl chain length. ILs have found application in many scientific fields the most recent being good solvents and stabilizing agents in the nanomaterial synthesis. Studies have showed that ILs not only stabilize as synthesized nanomaterials but also provide environmentally green routes towards nanomaterials engineering.
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    Thermolytic synthesis of cobalt and cobalt sulfide nanoparticles using Cobalt(II) NO Schiff base complexes as single molecular precursors
    (Turkish Journal of Chemistry, 2018) Khoza, Sandile H; Masikane, Siphamandla C; Mlowe, Sixberth; Ezekiel, Itegbeyogene P; Moyo, Thomas; Revaprasadu, Neerish
    Two novel N^O-type Schiff base ligands and the corresponding Co(II) complexes are reported. Thermo-gravimetric analysis indicated that the complexes are potential molecular precursors for the fabrication of cobalt andcobalt-containing nanomaterials. The significant difference in the thermal decomposition profiles is recognized as aninfluence of structural differences on the complexes. Thus, the complexes were thermally decomposed using the melt andhot injection methods to examine the properties of the obtained cobalt and cobalt sulfide nanoparticles, respectively.The reaction parameters employed during the fabrication processes, in addition to structural differences, influencedthe morphological and crystallographic phases and magnetic properties of the synthesized nanoparticles. We have in-vestigated the morphological properties and the crystallographic phase compositions of the nanoparticles by variouselectron microscopy and diffraction techniques, as well as energy-dispersive X-ray spectroscopy. The melt reactionsproduced phase-pure cobalt nanoparticles, which exhibit ferromagnetic behavior. The hot injection method utilized 1-dodecanethiol (DDT) as both sulfur source and capping agent. We indexed the DDT-capped cobalt sulfide nanoparticlesto cubic Co9S8and Co3S4phases using powder X-ray diffraction, high-resolution transmission electron microscopyimaging, and selected area electron diffraction. The crystallite sizes for Co9S8and Co3S4nanoparticles, based on theScherrer equation, were 12.4 nm and 14.1 nm, respectively. We find significant differences in the magnetic properties,attributed to nonmagnetic inclusions and vacancies due to the presence of S atoms.