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Carbon fiber-reinforced carbon aerogel composites (C/CAs) for thermal insulators were prepared by copyrolysis of resorcinol-formaldehyde (RF) aerogels reinforced by oxidized polyacrylonitrile (PAN) fiber felts. The RF aerogel composites were obtained by impregnating PAN fiber felts with RF sols, then aging, ethanol exchanging, and drying at ambient pressure. Upon carbonization, the PAN fibers shrink with the RF aerogels, thus reducing the difference of shrinkage rates between the fiber reinforcements and the aerogel matrices, and resulting in C/CAs without any obvious cracks. The three point bend strength of the C/CAs is 7.1 ± 1.7 MPa, and the thermal conductivity is 0.328 W m(-1) K(-1) at 300 °C in air. These composites can be used as high-temperature thermal insulators (in inert atmospheres or vacuum) or supports for phase change materials in thermal protection system.

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To achieve simultaneous removal of NO x and SO 2 in flue gas, an effective technology combined with ozone oxidation was explored in this paper. The simulated flue gas was initially oxidized by ozone (O 3 ), turning NO into NO 2 or N 2 O 5 , and then absorbed by alkaline slurries to achieve simultaneous removal of NO x and SO 2 . It was found that the MgO slurry was a suitable absorbent for the simultaneous removal of NO x and SO 2 . The operating parameters, such as the pH of the liquid phase, initial SO 2 concentration, and MgO concentration, were investigated for the NO 2 removal efficiency of the MgO slurry, where the optimal NO 2 removal efficiency (at ca. 75%) was obtained with the pH value at 6.5 and the MgO concentration at 0.02 mol/ L. In the case of N 2 O 5 , the absorption efficiency of the MgO slurry was maintained at a high level because of the rapid reaction between N 2 O 5 and H 2 O. Furthermore, it was noted that the absorption efficiency of SO 2 could be at a high level (i.e., approaching 100%) when the pH of the MgO slurry was above 4. Finally, the simultaneous removal mechanism and the reaction pathways were discussed on the basis of the experimental results.