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Abstract: The concentration and its distribution characteristics of TN, TP and COD in the ice layer and water layer during the icebound season in the Hulun Lake of Inner Mongolia showed that the pollutants could migrate from the ice layer to the water layer during the freezing process. The process of low temperature freezing has a good concentration effect on the pollutants in water body. A reasonable explanation of frozen concentrate effect was given from three aspects known as the liquid-solid phase equilibrium theory, crystallography theory and thermodynamics theory. Drawing inspiration from the phenomenon and its mechanism of frozen concentration effect, a tentative idea that we can use natural cool energy in wastewater treatment field was put forward. A reasonable technological process of freezing purification was designed, in which, more than 80% of TN, TP and COD in the original water can be removed through single stage frozen; more than 94% of TN, TP and COD can be removed through second stage frozen; more than 97% of TN, TP and COD can be removed through third stage frozen. Furthermore, parts of related parameters are optimized: the best cold area and water depth ratio is 2.22 and the best removing thickness of ice is 13.5cm in the experiment. [Copyright &y& Elsevier]

Abstract: To protect carbon/carbon (C/C) composites from oxidation at elevated temperature, an effective WSi2–CrSi2–Si ceramic coating was deposited on the surface of SiC coated C/C composites by a simple and low-cost slurry method. The microstructures of the double-layer coatings were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy analyses. The coating exhibited excellent oxidation resistance and thermal shock resistance. It could protect C/C composites from oxidation in air at 1773K for 300h with only 0.1wt.% mass gain and endure the thermal shock for 30 cycles between 1773K and room temperature. The excellent anti-oxidation ability of the double-layer WSi2–CrSi2–Si/SiC coating is mainly attributed to the dense structure of the coating and the formation of stable vitreous composition including SiO2 and Cr2O3 produced during oxidation. [ABSTRACT FROM AUTHOR]