粉煤灰碱熔-水热合成沸石用于水溶液中汞的吸附

摘要/Abstract

摘要： 汞被认为是危害最为严重的重金属之一。目前虽已有大量水处理技术可用于水中汞的去除,但由于成本较高等原因均未实现大面积的工业化应用。以工业固废粉煤灰为原料通过碱熔-水热法合成了沸石,可将其应用于水溶液中汞的吸附。结果表明:碱熔活化可以使得粉煤灰中稳定的莫来石、石英及非晶相矿物转变为钠铝硅酸盐、硅酸钠和钠霞石等矿物;这些矿物可溶于氢氧化钠溶液中,形成富含钠、铝、硅的碱性溶液;在适宜的水热条件下,通过调配铝硅比,可合成纯度较高的NaA型沸石;该法合成的粉煤灰基沸石可有效吸附水溶液中的Hg(II),去除率可达95%左右,吸附过程符合拟二级吸附动力学模型,反应速率同时受到内外扩散影响。

关键词: 粉煤灰, 碱熔-水热法, 沸石, 吸附, 汞

Abstract: Mercury is regarded as one of the most hazardous heavy metals. A variety of water treatment technologies are used to remove mercury in water. However, they may not be achieved large-scale industrial application, largely due to their high implementation costs. In this paper, zeolite was synthesized from industrial solid waste coal fly ash by alkali fusion-hydrothermal method and it was applied to the adsorption of mercury in aqueous solution. The results show that the stable mullite, quartz and amorphous minerals in coal fly ash are transformed into sodium aluminosilicate, sodium silicate and nepheline, which are dissolved in sodium hydroxide solution to form alkaline solution with plenty of sodium, aluminum and silicon. NaA zeolite with high purity is synthesized by adjusting the ratio of aluminum to silicon under a suitable hydrothermal conditions. The zeolite synthesized by this method adsorbs Hg (II) in aqueous solution effectively, and the adsorption removal rate reaches about 95%. The kinetic studies show that the pseudo second-order rate equation fits the experimental data well, and the reaction rate is affected by internal and external diffusion at the same time.

Key words: coal fly ash, alkali fusion-hydrothermal method, zeolite, adsorption, mercury

中图分类号:

燕可翀, 李子鹏, 李杨敏, 王平治. 粉煤灰碱熔-水热合成沸石用于水溶液中汞的吸附[J]. 硅酸盐通报, 2020, 39(12): 3939-3944.

YAN Kechong, LI Zipeng, LI Yangmin, WANG Pingzhi. Adsorption of Mercury in Aqueous Solution by Zeolite Prepared from Coal Fly Ash Using Alkali Fusion-Hydrothermal Method[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2020, 39(12): 3939-3944.

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