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Rice husk was used as a raw material to fabricate silicon carbide (SiC) ceramics. Carbothermal reduction was used together with in-situ reaction bonding as the preparation method. Rice husk was carbonized at the temperature around 700 °C in an incineration furnace. Carbonized rice husk was ground and treated with hydrochloric acid solution. After grinding, the sample powders were mixed with silicon metal powder and sintering additives (alumina (Al2O3) and magnesia (MgO)). The mixed powders were pressed and then pyrolyzed at various temperatures and pyrolysis patterns in argon atmosphere. Silicon carbide, as the main crystalline phase, was obtained in all pyrolized samples. Cristobalite was found together with silicon carbide in the samples which pyrolized only lower than 1500 °C. Amount of silicon carbide particle was increased at higher pyrolysis temperature while silicon carbide whisker was decreased. Weight loss, shrinkage and porosity of the pyrolized samples were investigated. Weight loss and shrinkage of the samples increased when increasing pyrolysis temperature while porosity decreased.

Carbon and amorphous silica from rice husk charcoal was prepared by carbonization of rice husk in an incineration furnace around 700 °C. The rice husk charcoal was taken as a precursor in the synthesis of carbon and zeolite NaA composites by hydrothermal method at various synthesis temperatures of 80-110 °C and for 2-8 hour. The composite powder was formed into rectangular shape of 10 mm width, 60 mm length and 10 mm thickness by hydraulic pressing at 60 MPa with 1% of carboxy methyl cellulose mixed with 5-20% of phenolic resin as binders. Samples were fired in a tubular furnace with 5% CO2+N2 gas flow at 300-700 °C for 1 hour as the thermal activation of carbon and sintering of the composite samples. Activated carbon and zeolite NaA composites were characterized in terms of phase analysis, morphology, thermal stability, mechanical strength, calcium ions absorbtivity and specific surface area by x-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), three points bending, inductive coupled plasma-optical emission spectroscopy (ICP-OES) and brunauer-emmett-teller technique (BET), respectively.

Silicon carbide (SiC) ceramics were prepared by carbothermal reduction together with in-situ reaction bonding. Raw rice husk was carbonized in an incineration furnace. The carbonized rice husk was ground and was then treated with hydrochloric acid by varying concentrations. The sample powders were mixed with silicon metal powder and pyrolyzed at various temperatures in either argon or nitrogen atmosphere. Silicon carbide phase was found in all pyrolyzed samples. Cristobalite was found in argon atmosphere pyrolyzed samples while silicon oxynitride was found in the samples pyrolyzed in nitrogen atmosphere at lower than 1500 °C. Silicon carbide whisker is the main phase on the surface of pyrolyzed sample. Increasing pyrolysis temperatures decreased the amount and size of silicon carbide whisker but increased the silicon carbide particle. Porosity and weight loss of samples after pyrolysis were increased with increasing temperatures due to the reaction in the system.

The La0.56Sr0.4Co0.2Fe0.8O3-δ(LSCF) perovskite cathode, substituted by Sr and Fe at the A and B sites, respectively, is a good candidate for intermediate temperature solid oxide fuel cell (IT-SOFC) applications. The powders were prepared by sol-gel method using various metal nitrates as starting materials. The adipic acid was used as a chelating agent and ethylene glycol as a dispersant. The gel precursor was heated at 700 °C for 4 h to obtain LSCF cathode powders. X-ray diffraction pattern showed the single phase of the perovskite structure. The microstructure of LSCF materials was observed by scanning electron microscopy which was loosely aggregated and could be ground easily into fine powders. The average particle size of the powders was found to be around 80-200 nm. TGA/DTA techniques exhibited the weight loss after high temperature process. It was found that no weight loss after 550 °C suggests the completion of combustion process.

Honeycomb structures of TiO2-modified hydroxyapatite composite (HA/TiO2) were fabricated using extrusion technique. The mixture formulations of HA/TiO2 extrusion pastes (S1-S4) were investigated to optimize the process. The filtering effectiveness of the HA/TiO2 honeycombs was evaluated by photocatalytic activity measurement and a bactericidal test. The effects of sintering temperature and honeycomb thickness on photocatalytic and antibacterial activities were additionally studied. The S3 and S4 honeycomb samples, sintered at 650°C, exhibited a similar trend in reducing methylene blue concentration. At 800°C, the S3 honeycomb sample showed a slightly faster reduction in methylene blue concentration compared to the S4 honeycomb. Honeycomb samples of 2 and 5 cm in thickness showed significantly greater photocatalytic activity than that of 1 cm such that methylene blue concentrations rapidly decreased after UV exposure for 24 hours. The S3 and S4 honeycomb samples also exhibited decomposition of both gram-negative E. coli and gram-positive S. aureus. Approximately 50% of gram-positive S. aureus and gramnegative E. coli were decomposed by the honeycombs in the sample-thickness dependent manner after 2 hours of UV exposure. Low survival ratios of bacteria (5% - 10%) were observed after 6 hours of UV exposure and the 2 mm and 5 mm thick honeycomb samples showed the greatest and most similar antibacterial activities.