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The weak compressive strength of dried ceramic foams is a disadvantage of fabricating ultralight ceramic foams, especially for the ceramic foams with porosity exceeding 95%. In this study, dried alumina foams were enhanced by agar and PVA-freezing-thawing using sodium dodecyl sulfate as surfactant. It is found that the two additives have no negative influence on adsorption of sodium dodecyl sulfate on alumina particles as well as the hydrophobic character of alumina particles. Stable alumina particle-stabilized foams were prepared with less than 0.5 wt% agar and 1.0 wt% PVA. High additive concentration above the critical values weakens stability of wet foams, which is probably due to the aggregate of alumina particles caused by long-chain molecules connecting. The compressive strength of dried alumina foams has a significant improvement with the employment of agar and PVA-freezing-thawing. The dried foams prepared with 1wt% PVA assisted by freezing-thawing has porosity of 97.1% and compressive strength of 0.16 MPa, which could maintain integrity of dried foams without destruction in the fabricating process. [ABSTRACT FROM AUTHOR]

In this work, gangue/palygorskite composite microspheres were fabricated through spray drying process and activated by calcination treatment. Its microstructure and adsorption capacity for the removal of dye (MB) were also studied, systematically. Results showed that kaolinite, α‐quartz and palygorskite were the major phases in microspheres after proper calcination (lower than 900°C). BET‐specific surface area of the microspheres reached the maximum value of 62.23 m2/g at 700°C, and then decreased with further increasing the heating temperature. In general, composite microspheres showed the largest adsorption capacity of MB after heat‐treated at 700°C. The qmax of MB onto microspheres was 29.9‐51.9 mg/g. The adsorption process of MB onto microspheres was well described by both the pseudo‐second‐order kinetic and Langmuir isotherm model. The composite microspheres also had extraordinary recyclability. This novel microsphere could be employed as a candidate for novel absorbent and filter medium in the practical application for dye treatment in industrial applications. [ABSTRACT FROM AUTHOR]

Abstract: In order to investigate the relationship between pore structure and thermal conductivity as well as mechanical strength, porous alumina ceramics (PAC) with various pore structures were fabricated, using starch as the pore‐forming agent. Fractal theory was employed to characterize the pore size distribution more accurately than ever used parameters. The results show that the increase in starch content in PAC leads to an enhanced porosity, a higher mean pore size, and reduced fracture dimension, thermal conductivity and strength. The fractal analysis indicated that the fractal dimension decreases gradually and reaches its minimum value with increasing the starch content up to 25 wt%, but the further incorporation results in an opposite trend. It is suggested from micro‐pore fractographic analysis that the optimization of both thermal insulation performance and mechanical strength are positively correlated with the increase in the mean pore size and proportion of 2‐14 μm pores but negatively corrected with the porosity. These results provide a new perspective and a deeper understanding for fabrication of PAC with both excellent thermal insulation and mechanical performance. [ABSTRACT FROM AUTHOR]