Siti Aida Ibrahim

Effect of pH on TiO2 Nanoparticles via Sol-Gel Method

A series of titania nanoparticles was successfully synthesized via sol gel method using titanium tetraisopropoxide as a precursor. In this paper, data concerning the effect of pH towards the development of TiO2 nanoparticles is reported. The samples were characterised by x-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD results showed the existence of nanocrystalline anatase phases with crystallite size ranging from 7-14 nm. Surface morphological studies obtain from SEM micrograph showed the particles with rodlike shape are rutile while the spherical shapes are anatase in nature. It was also found the pH of the solution affect the agglomeration of the particles. Results of photocatalytic studies exhibits that titania powder prepared at pH 9 has an excellent photocatalytic activity with degradation 74.7% within 60 minutes.

Influence of Calcination Temperature towards Fe-TiO 2 for Visible-Driven Photocatalyst

TiO2 is one of the most promising photocatalysts that is widely used for environmental clean-up due to its ability to degrade organic pollutants in air or water. The purpose of this study is to enhance the photocatalytic activity of TiO2 by absorbing energy in visible light region in order to degrade pollutants. In this study, the nanostructured Fe-TiO2 was successfully synthesised via a combined method of sol-gel and calcination process. The calcination temperatures used varied from 400 to 800 °C. The as-prepared samples were characterized by X-ray diffraction (XRD), FESEM and UV-Vis spectroscopy (UV-Vis). XRD results show that the phases of TiO2 are dependent on calcination temperature. It is found that both TiO2 and Fe-TiO2 phases were transformed from anatase to rutile as the temperatures were increased. FESEM images revealed that the particle size was agglomerated and the average grain size was about 54 to 66 nm. UV-Vis analysis indicated that the incorporation of Fe and varied calcination temperature may affect the optical properties as the absorption profile was shifted from 445 nm to 585 nm. Thus, this results show that Fe-TiO2 is a highly potential photocatalyst to degrade pollutants under visible light irradiation.

Heat transfer of Al2O3 nanofluids in microchannel heat sink

Microchannel heat sink creates an innovative cooling technology to remove large amount of heat from small area. Recently, nanotechnology gain interest to explore the microchannel cooling benefits of nanofluids as working fluid. The objective of this study is to investigate the effect of heat transfer to Al2O3 nanofluids after used as working fluid in the microchannel. In this study, the microchannel was design in square shape with a cross section of 0.5×0.5 mm2 and made by copper. The experiment was conducted in laminar flow with Reynolds number ranging approximately from 633 to 1172. The present study was focused on heat transfer of Al2O3 nanofluids in microchannel heat sink at concentration of 1.0 wt. % and 2.5 wt. % dispersed in water. The heat was produced at bottom of the heat sink is 325 W. The computational simulation method was carried out to validate the experimental results. It was observed that the heat transfer rate is higher when using Al2O3 nanofluids compared to water. However, according to...

Degradation of Methyl Orange using TiO[sub 2] as Photocatalyst

During the last few years, due to the population explosion and the increased industrial activity, environmental pollution, has been pointed as one of the major problems of modern society. In this scenario, textile industry stands out as it produces a large amount of coloured dye effluents which are toxic and biodegradables [1]. Among the different types of dyes used in textile industry, 60–70% is azo compound. An extensive research on photocatalysis TiO2 has attracted significant attention for solving these problems due to its high potential for ensuring the complete destruction of organic compound in the aqueous medium [2–3].

Effect of annealing atmosphere towards TiO 2 nanoparticles on their photocatalytic performance in aquoues phase

TiO2 is one of the most semiconductors metal oxides used in many applications covering various field such as optoelectronics, medicine, sensor devices and catalyst [1]. Such applications are depended strongly on the crystalline structure, morphology and particle size [2]. Among the common crystalline form of titania, anatase is proven to be excellent photocatalyst compared to rutile and brookite.