凹凸棒石纳米铁复合材料的制备及应用探讨

Preparation and Application of Palygorskite / Nano-iron Composite

通过对凹凸棒石进行湿法提纯和酸处理改性提高凹凸棒石的纯度、比表面积和吸附性能;将提纯改性后的凹凸棒石作为载体,以硼氢化钾作为还原剂,在氩气保护下采用离子交换法制备凹凸棒石纳米铁复合材料,解决纳米铁稳定性差、容易凝聚成团的问题,从而增大纳米铁与污染物反应的有效面积。与纳米铁相比,凹凸棒石纳米铁复合材料较稳定,易于保存。以地下水中常见的硝酸盐为目标污染物,探讨了将凹凸棒石纳米铁复合材料应用到可渗透反应墙技术、抽出处理技术及注入修复技术中的方法。应用研究成果表明,经上述技术处理后,地下水硝酸盐浓度可得到有效去除。

The purity,specific surface area and adsorption properties of palygorskite were improved through wet purification and acid modification. The modified palygorskite was used as a carrier and KBH4 as a reducing agent to prepare palygorskite / nano-iron composite material using ion exchange method under the protection of argon gas.Hence,the stability of nano-iron could be enhanced,iron-nano particles were prevented from condensing into groups,and the effective area of the nano-iron reacting with pollutants could be increased. Compared with nano-iron,palygorskite / nano-iron composite is more stable and easier to store. Furthermore,with nitrate as target contaminant in groundwater for example,the usage of palygorskite / nano-iron composite in permeable reactive barrier technology,extraction processing technology and injection processing technology in removing nitrate was discussed.Treated by these techniques,the nitrate concentration in groundwater can be effectively degraded.