No abstract

Photocatalytic activity in TiO2 attract great attention because it promising application in contaminations on degradation and energy conversation. However there is a need on TiO2 band gap modification to be equivalent with the visible light. Thus, inviting several method of addition certain elements including in this study, the additional of graphene oxide (GO) was investigated. GO were prepared by Hummer method before it was added into TiO2. The formation of GO from it graphite precursor had been confirmed by Raman spectroscopy. The existence of D-band at wavelength of 1328 cm-1 and G-band at 1573 cm-1 shows the formation of GO. The GO was then added in different concentration; 0.0 - 1.0 wt% into TiO2. The photocatalytic activity was determined using calculating the photodegradation efficiencies of methylene blue under UV light irradiation. The experimental results showed that the photodegradation of MB were increased with higher dopants concentration due to reduction of band gap energy of TiO2 from 3.2 eV to 3.0 eV for 1.0 wt% GO-with the photodegradation efficiency of GO doped TiO2 was 61.38%.

In this project, iron mill scale has been used to produce iron powder that can be used within the Powder Metallurgy process. To achieve this objective, the iron mill scale needs to be refined. This involve the work of grinding the iron mill scale to an effective particle size, which is 300μm. Latter, the grounded iron mill scale will undergo the magnetic separation process. The purpose of this process is to remove any non-magnetic material. Than the following process is to fully oxidize and reduce the iron mill scale to form pure iron powder. From this step an optimum value for maximum heating temperature, heating rate and heating cycle was determined. Than in order to determine whether the oxidation and the reduction process have completely achieved their objective, the iron oxide and the iron powder that have been produced from both process, was characterized using X-Ray Diffraction Analysis (XRD) and X-Ray Florescent Analysis (XRF) technique. From the oxidation process, it is obvious that sample C gave higher oxidation percentage, which is 11.22%. While Reduction 2 shows the desirable result, which is 29.51% of reduction, involving a low cost compared to other reduction process.

The relations between the milling periods with the iron mill scale particle size have been studied. Iron mill scale has been chosen for this research due to the nature of itself, as a by-product. From this research, the average optimum size for the final iron mill scale particle size intended to produce is at 300 μm. Raw iron mill scale received from the industries was in the form of chip with the average size of 10 mm across and 1.5 mm thickness. Three different samples from three different steel mill companies have been used for this study. Rolling ball mill has been used to mill the iron mill scale with two different milling periods, which were two hours and six hours. After the milling process, the iron mill scale was sieved using sieving machine to a few specified grating sizes. Weight of each sample collected from each grating size was calculated in order to get the percentage of the particle size distribution of the iron mill scale after the milling process. Sample collected from Steel Mill 1 (SM1) and Steel Mill 3 (SM3) showing finer particle size produced after the milling period of six hours as compared to two hours. However sample from Steel Mill 2 (SM2) showing different trend of particle size collected as compared to SM1 and SM3. Coarser particle size was collected after the milling periods of six hours as compared to two hours. Characterization process have been conducted to all mill scale samples from each steel mill company in order to determine the relationship between the mill scale properties and the result gathered after the milling process.

A single-phase of perovskite-type oxide material can be prepared at a processing temperature relatively lower than 1000 °C through a sol-gel method. However, it is affected by the nature of chemical additives employed during the synthesis process. In the present work, sol-gel derived lanthanum strontium cobaltite, La0.6Sr0.4CoO3-δ (LSC64) material is prepared using various non-ionic surfactants namely polyoxyethylene (10) oleyl ether (Brij-97), polyoxyethylene octyl phenyl ether (Triton-X-100) and polyoxyethylene (20) sorbitan monooleate (Tween-80). The prepared powders of the LSC material is subsequently subjected to the thermal decomposition, phase formation and microstructure analysis by a thermal gravimetric analyzer, an X-ray diffractometer and a scanning electron microscope (SEM), respectively. The as-synthesized powders are calcined at different temperatures based on the thermal gravimetric analysis results. X-ray diffractometer results reveal that all of the calcined powders consist of more than 90 % perovskite phase of LSC64 and other secondary phases such as cobalt oxide, lanthanum oxide and strontium carbonate. The Brij-97-based and Tween-80-based calcined powders have morphology of typical clump-like network structure, while the Triton-X-100-based calcined powder has morphology of flake-like network structure.