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Development of Novel Porous Phosphorous Adsorbent by Effective Uses of Waste Cement and Flyash

有效利用废水泥和粉煤灰开发新型多孔磷吸附剂

基本信息

批准号：
15560707
负责人：
SHIOMI Haruhisa
金额：
$ 2.37万
依托单位：
Kyoto Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Mechano-chemically activated wollastnite powder was used as a starting material to obtain consolidated bodies by a carbonation method. Fly ash as aggregate and hydrated cement as a calcium resource were added to wollastnite in order to improve the phosphorus removal property of the consolidated bodies. The wollastnite consolidated bodies obtained these additives showed higher phosphorus removal ratio than that of pure wollastnite. However, the sample obtained at low carbonation temperature generates fine HAP precipitate in a phosphoric acid aqueous solution due to significant increase in pH. On the other hand, when the carbonation temperature is high, the phosphorus removal ratio markedly decreased. This is caused by the decrease in the dissolved calcium ion concentration due to the carbonation of calcium hydroxide in cement. Therefore, the precise control of carbonation conditions is necessary when the hydrated cement as a calcium resource.When gypsum was used as a calcium resource instead of hydrated cement, the phosphorus removal ratio was independent of the carbonation temperature and higher than that of pure wollastnite. The sample containing gypsum did not generate fine HAP precipitation regardless carbonation temperature. Moreover, the sample containing gypsum showed satisfied phosphorus removal ratio at 25% amount of pure wollastnite.The cyclic immersion test in the phosphoric acid aqueous solution showed the significant decrease of the phosphorus removal ratio with increasing immersion cycle. Five times of immersion decreased the phosphorus removal ratio of the sample to 50% of initial value. However, the phosphorus removal ratio deteriorated sample was recovered to 95% of initial value by washing the sample in 0.005mol/l hydrochloric acid to remove HAP precipitated on the surface of the sample.

以机械化学活化的硅灰石粉末为起始原料，通过碳化法获得固结体。在硅灰石中添加粉煤灰作为骨料，水化水泥作为钙源，以提高固结体的除磷性能。这些添加剂获得的硅灰石固结体表现出比纯硅灰石更高的除磷率。然而，在低碳酸化温度下获得的样品由于pH值显着增加而在磷酸水溶液中产生细小的HAP沉淀。另一方面，当碳化温度较高时，除磷率显着降低。这是由于水泥中氢氧化钙的碳化导致溶解钙离子浓度降低所致。因此，水化水泥作为钙源时，对碳化条件的精确控制是必要的。以石膏代替水化水泥作为钙源时，除磷率与碳化温度无关，且高于纯硅灰石。无论碳酸化温度如何，含有石膏的样品都不会产生细小的 HAP 沉淀。此外，含石膏的样品在纯硅灰石用量为25%时表现出令人满意的除磷率。在磷酸水溶液中的循环浸泡试验表明，随着浸泡次数的增加，除磷率显着下降。经过5次浸泡，样品的除磷率降至初始值的50%。然而，通过将样品用0.005mol/l盐酸清洗以去除样品表面沉淀的HAP，除磷率恶化的样品恢复至初始值的95％。