Papers by Keyword: Macroporosity

Abstract: A well-defined porous ceramic having effective pore size less than 1 µm was fabricated by slip casting technique which provides a low-cost and single-stage filtration process. This single-stage filtration process removed suspended solids and pathogenic organism. In this study, diatomaceous earth was used as pore forming agent in clay based ceramic body. Varied amount of diatomaceous earth was used with fixed proportion of china clay, ball clay and lime stone. X-ray fluorescence spectroscopy (XRF) was used to determine the composition of raw materials and final sintered filter body. In terms of porosity and flow rate, 25% diatomaceous earth shows better filtration property. It was found that total porosity increased with decreasing milling time. As the firing temperature increased, porosity decreased rapidly after 1100 °C. However, the change of porosity in firing range of 1000 °C–1100 °C was found very small. Mercury intrusion porosimetry was used to measure the pore size and its distribution. An effective intra-particle pores in a range of 0.2-0.5 μm was identified. Inter- and intra-particle pores were observed using scanning electron microscope (SEM). Microbial removalefficiency of 99.99% was measured, while water flow rate was found in a range of 200-700 ml/hour.

Abstract: The present work was performed to improve the mechanical strength of porous calcium phosphate blocks by adding a little amount of montmorillonite mineral to the calcium phosphate composition. 3.5 wt % of the montmorillonite mineral was added to the slurry of precipitated hydroxyapatite and the porosity was produced by infiltration of a polymer template. After the firing process (1200 oC), the compressive strength, phase composition, morphology and dissolution behavior of the porous bodies were evaluated by appropriate techniques. It was found that the additive improved the mechanical strength but decreased the dissolution rate of the porous calcium phosphate body. Also the final composition of the porous block (i.e. hydroxyapatite, HA, and β- tricalcium phosphate, β-TCP) was not influenced through the presence of the additive. It is suggested that the montmorillonite mineral can improve the sintering performance of the HA and β- TCP.

Abstract: In this work an injectable and self setting calcium phosphate/albumen foam is developed. The effect of both the amount of albumen and the particle size of the starting a-tricalcium phosphate (a-TCP) powder on the injectability of the cement paste is studied. X-ray diffraction (XRD) and infrared (IR) analysis of the samples reveal that the hydrolysis of a-TCP to calcium deficient hydroxyapatite (CDHA) is not affected by the addition of albumen. A foamed structure formed by spherical pores with diameters between 100 and 500 µm is observed by SEM. This porous structure is maintained after injection of the paste, although some deformation of the pores is produced due to the extrusion process. The injectability of the cements is increased by the presence of albumen as compared with cements prepared in the same conditions but without foaming agent.