Recently, plant-mediated route or green approach for preparing metal and metal oxide nanoparticles has received enormous attention due to the ease of preparation and environmental friendliness when compared to physical and chemical methods. Plants contain phytochemicals which have been proposed as bio-reductants and capping agents for forming metal nanoparticles. Therefore, this study was aimed to prepare magnesium oxide nanoparticles (MgONPs) using aqueous extract of Manihot esculenta leaf. The leaf extract was first analyzed in a gas chromatograph-mass spectrometer (GC-MS) to examine the phytochemicals present. Then, the MgONPs formed were evaluated using UV-Visible (UV-Vis) spectrophotometry, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy, to confirm the formation of MgONPs and to determine the morphology, elemental composition, shape and size, phase composition and nature of bonds present in the sample. Results revealed the formation of monodisperse, hexagonal shaped MgONPs of average size 36.7 nm having potentials for application in catalysis and as antimicrobial agent. Hence the process reported herein could be optimized for large-scale preparation of MgONPs.

Porous silica was synthesized via the sol-gel process using clay obtained locally from Ijero-Ekiti in Ekiti State, Nigeria and compared with silica synthesized under similar conditions from sodium metasilicate (Na 2 SiO 3 ) obtained comercially. The clay was initially refluxed with sodium hydroxide (NaOH) for 2 hours to extract SiO 2 to form Na 2 SiO 3 , which was subsequently hydrolyzed to form a gel. The gel obtained was washed with deionized water to get rid of impurities, dried and calcined at 800˚C for 3 hours. The obtained silica powders were characterized using atomic absorption spectrophotometer, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the vibrational modes and diffraction patterns of the silica derived from commercial Na 2 SiO 3 and that prepared from clay were similar containing pure amorphous SiO 2 . The morphology of the commercially obtained silica showed better arrangement of particles and exhibited slightly lesser porosity (62.4%) compared to that derived from clay which had a porosity of 65.5%. The result indicates that clay has a potential for use as an environmentally safe and economic starting material for preparing porous silica instead of high quality precursors.

No abstract

Artificial bone graft materials formed from wollastonite have been extensively used in bone repair because of their high degree of bioactivity and biocompatibility, thereby justifying the development of a protocol for large-scale production. This work reports a novel route for preparing wollastonite via the sol-gel process using bentonite clay as a cheap silica source. The obtained wollastonite was characterized for morphology, elemental composition, phase composition and bioactivity using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction and Fourier transform infrared spectroscopy. Results obtained revealed that wollastonite phase was successfully formed in the material and it showed ability to induce formation of apatite within 0.5 day in biological fluid, an indicator for bone-bonding capability. Overall, the wollastonite prepared from the bentonite clay exhibited properties comparable to that synthesized from commercially obtained sodium metasilicate. Hence, our synthetic route may be useful for commercial-scale preparation of wollastonite.

No abstract