粉煤灰基地质聚合物固化Pb^(2+)的化学形态分析

Chemical Speciation of Pb^(2+) Solidified by Geopolymer Based on Fly Ash

本文采用连续化学萃取法,对比分析了粉煤灰基地质聚合物和水泥中Pb2+的化学形态及迁移规律。试验结果表明:中性环境下粉煤灰基地质聚合物与水泥对Pb2+的固化能力相当,但Pb2+的存在形态不同;在加速试验条件下,粉煤灰基地质聚合物对Pb2+的捕集率超过水泥。试验环境由中性向酸性转化时,水泥固化体中Pb2+由Ⅴ型向Ⅳ、Ⅲ型迁移,粉煤灰基地质聚合物中Pb2+由Ⅴ型向Ⅱ型迁移。粉煤灰基地质聚合物与水泥固化Pb2+的固化机理与迁移规则存在差异。

Sequential extraction method was used to analyze the chemical state and migration of Pb2＋ solidified by geopolymer based on fly ash and cement.The result showed that geopolymer based on fly-ash was equal to cement on solidification of Pb2＋ in neutral environment although the chemical states of Pb2＋ were different.In the acceleration test condition,the geopolymer based on fly ash was more efficient than cement in the case of Pb2＋ solidification.When the test condition converted from natural to acidic,the type of Pb2＋ migrated from Ⅴ to Ⅳ and Ⅲ in cement while in the geopolymer based on fly-ash the type of Pb2＋ converted to Ⅱ.The solidification mechanism and migration rule of Pb2＋ in cement and geopolymer were different.