Permeability Of Porous Ceramics Research Articles

Durable hydrophobic ceramics of Al2O3–ZrO2 modified by hydrophilic silane with high oil/water separation efficiency

Separating materials of oil/water are widely used to deal with oil leakage and industrial oily wastewater. Herein, hydrophobic–oleophilic porous ceramics of Al2O3–ZrO2 were prepared by combustion synthesis-molding method and modified with 3-amino-propyltriethoxysilane (APTES). The effects of Al2O3–ZrO2 mole ratio, starch content and sintering temperature on permeability of porous ceramics were investigated in detail. When the molar ratio of Al2O3–ZrO2 is 1:0.15 and the amount of starch is 35 wt%, the porous ceramics with average pore diameter of about 42 nm and porosity of about 46% can be obtained after sintering at 1450 °C for 2 h. APTES was adopted to modify the porous ceramic of Al2O3–ZrO2 to construct the hydrophobic surface. The optimum conditions of modification for the Al2O3–ZrO2 ceramic were that the time was 4 h, the temperature was 70 °C and the modifier concentration was 2%. Most notably, the as-prepared hydrophobic ceramic was a rare example that adopted hydrophilic molecule to build hydrophobic material. Due to the favorable permeability and hydrophobicity, the Al2O3–ZrO2 ceramic was designed into sand core to separate oil/water mixture. The ceramic displays high separation efficiency (93%), good reuse performance (10 cycles) and super abrasion resistance (10 times).

Permeability of porous ceramics by X-ray CT image analysis

This work presents a method to 1) statistically characterize the complex geometry of porous material microstructures, 2) parameterize these random microstructures into statistically condense, feature rich metrics, and 3) relate these metrics to material properties such as permeability. This method is applied to porous synthetic cordierite and aluminum titanate materials covering a range of 40%–70% porosity and 8–18 μm median pore size (as measured by mercury intrusion porosimetry), using X-ray computed tomography images of the porous microstructure. Direct simulations of the microstructures were made to estimate effective permeability and correlations are presented to microstructural metrics. High quality relationships are established, specifically utilizing 2-point correlation functions and lineal path function characteristic dimensions. Results are compared to legacy methods such as the widely known relationships proposed by Kozeny-Carman and Kuwabara.

Permeability of Porous Ceramics by X-Ray CT Image Analysis

This work presents a method to 1) statistically characterize the complex geometry of porous material microstructures, 2) parameterize these random microstructures into statistically condense, feature rich metrics, and 3) relate these metrics to material properties such as permeability. This method is applied to porous synthetic cordierite and aluminum titanate materials covering a range of 40%-70% porosity and 8-18 μm median pore size (as measured by mercury intrusion porosimetry), using X-ray computed tomography images of the porous microstructure. Direct simulations of the microstructures were made to estimate effective permeability and correlations are presented to microstructural metrics. High quality relationships are established, specifically utilizing 2-point correlation functions and lineal path function characteristic dimensions. Results are compared to legacy methods such as the widely known relationships proposed by Kozeny-Carman and Kuwabara.

Permeability of Porous Ceramics Considering the Klinkenberg and Inertial Effects

The literature reports that permeability constants differ in experiments conducted with gases or liquids. This behavior, known as the Klinkenberg effect, has been explained based on the gas‐slippage theory. We show here that inertial effects not considered by Darcy's law are the cause of variations in the gas permeability constant, kgas, with the mean pressure, Pm. The dependence of kgas and Pm on fluid flow is fully explained by the proposed model, based on Forchheimer's equation. The use of the gas‐slippage theory is unnecessary to explain variations in kgas obtained by Darcy's law.

Estimation and determination of the permeability of porous ceramics

The possibility of estimating the permeability of porous ceramic materials both with mercury and with gas liquid pore diagrams and based on model concepts concerning the porosity and average size of the constituent particles in the material was demonstrated. It was shown that the permeability of a porous material and the average pore radius can be directly determined with the linear segment of the reverse GLP curve and the capillary sinuosity can be calculated with it.

Procedure for determining the permeability of porous ceramics

Procedure for determining the permeability of porous ceramics