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The sol-gel synthesis and characterization of mullite precursor derived from rice husk silica and aluminum nitrate hydrate [(Al(NO 3 ) 3 .9H 2 O] has been investigated. The samples were characterized using Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD) coupled with Rietveld analysis, and scanning electron microscopy (SEM). FTIR results showed the presence of Si-O-Si, Al-O-Al, and Si-O-Al functional groups, which were associated with mullite, corundum, quartz, and cristobalite, as verified by XRD analysis. It is concluded that mullite formation started at 1150 o C, and its abundance increased rapidly with an increase in temperature from 1150-1350 o C, resulting in increased phase content from 30.9 to 67.7 wt%. Although mullite was formed at a low temperature, the complete reaction between corundum and silica to form mullite was not achieved.This finding demonstrated that rice husk silica is a potential alternative raw material for the production of mullite ceramic.

A series of titania thin films was prepared by chemical bath deposition (CBD) of TiCl 3 on indium tin oxside (ITO) glass at room temperature, followed by calcinations at 500°C for 4 hours. The effect of cyclic deposition on phase composition, microstructure and electrical resistivity of TiO 2 thin films was characterised using X-ray diffraction, scanning electron microscopy and four-point probe respectively. Results showed that TiO 2 films produced by single deposition cycle were amorphous. In contrast, those produced by 5 and 6 deposition cycles were partly amorphous and partly crystalline with the formation of rutile. Both the film thickness and electrical resistivity increased with an increase in the number of deposition cycles.

This study acquires the potential of rice husk silica for production forsterite precursors using sol-gel method. The samples preparation were conducted by mixing magnesium oxide sol from Mg(NO 3 ) 2 .6.12H 2 O with silica sol extracted from rice husk, with three different composition ratios of MgO to SiO 2 are 1:1, 2:3 and 3:2 by weight and sintered at 900 o C. The samples were characterized using Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD),differential thermal analysis (DTA), followed by scanning electron microscopy (SEM). The FTIR results showed the presence of Si-O-Si, Mg-O and Mg-O-Si functional groups, which were associated with forsterite, enstatite, cristobalite and periclase, according to the XRD analysis. The formation of forsterite (Mg 2 SiO 4 ) is composition-dependent as revealed the increase of forsterite intensity after sintered at 900 o C in ratio 3:2. The surface morphology of non-sintered samples shows that particle and grain size were larger than particle and grain size of sintered samples. Also, SEM analysis of sintered samples clearly shows the presence of regular particle size with smaller grain size was found in ratio of MgO to SiO 2 is 3:2. DTA analysis revealed that the formation of forsterite increased with increasing temperature. In addition, the electrical resistivities of the samples were found in the range of 0.75 x 10 13 to 3.30 x 10 13 Ω-cm, demonstrating that the samples exhibit good potential as isolator.

In this research, nano-size MgO (NS-MgO) was prepared from MgCl2 solution using aqueous extract of Moringa oleifera leaves (AEMOL) as green agent. Preparation procedure involved mixing of MgCl2.6H2O solution and the AEMOL, followed by dropwise addition of NaOH solution. The formation of NS-MgO in this synthesis was confirmed using UV-Vis absorption. The spherical crystal structure of NS-MgO was confirmed by XRD analysis. The average particle size of the synthesised NS-MgO was found between 40–70 nm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images and particle size analyser (PSA) results. Based on the maximum inhibition concentration (MIC) it was found that the NS-MgO has good antibacterial activity against S. aureus, E. faecalis, E. coli, and S. dysenteriae bacteria (MIC values: 250–500 μg ml−1), and much stronger antifungal activity against A. flavus, A. niger, and C. albican (MIC values: 62.5–125 μg ml−1). These findings suggest prospective potential of NS-MgO synthesised as therapeutic candidate for the treatment of candidiasis.

This study investigated the use of electrochemical method to prepare aluminosilicates from rice husk silica and aluminum metal. The aluminosilicate precursors were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy. The precursors were subsequently sintered at 700-1400 °C and their microstructures and phase compositions were characterized. Results showed that the proposed method could be used to prepare aluminosilicates with high uniformity in terms of surface morphology and the particle size with mullite and quartz as the major phases formed.

This study was carried out to examine the potential of conversion of rubber seed oil into biodiesel. A series experiments was conducted using CaO and CaO/SiO 2 as catalyst and coconut oil as co-reactant, with the main purpose to assess the effect of calcination temperatures on the performance of the catalysts. The results obtained demonstrate that the use of coconut oil as coreactant significantly promoted conversion of fatty acids in rubber seed oil into their corresponding methyl esters. It was also found that the catalytic activity of both CaO and CaO/SiO 2 was significantly influenced by calcination temperatures and at the same temperature, CaO/SiO 2 exhibited higher activity than unsupported CaO. The highest yield was achieved using CaO/SiO 2 catalyst subjected to calcination at 800 o C

This study assessed the potential of liquid smoke as substitute for nitric acid for production of rice husk silica using sol-gel method. The efficacy of liquid smoke was compared to that of 10% HNO 3 solution in terms of the volume required and the mass of silica obtained. Further evaluation was made by comparing the characteristics of the silica as revealed by several characterization techniques include Fourier infrared spectroscopy, x-ray diffraction, scanning electron microscopy, and particle size analysis. No significant difference between the volume of the liquid smoke and the HNO 3 solution required, as well as between the mass of silica obtained. Both samples display practically similar functionality and structure. The most interesting finding is that the silica obtained using liquid smoke exhibits more homogeneous surface morphology and narrower particle size distribution. Considering its environmentally friendly nature, it was concluded that liquid smoke is more advantageous than HNO 3 solution.