改性凹凸棒土/纳米铁复合材料去除地下水NO_3~--N的研究

采用液相还原法制备改性凹凸棒土/纳米铁复合材料(简称复合材料),考察了该复合材料的稳定性及其作用下"三氮"(NO_3~--N、NH_4~+-N、NO_2~--N)的变化情况,阐明了地下水环境因素(DO、温度、光照)对复合材料去除NO_3~--N的影响。模拟地下水环境时,3种材料去除NO_3~--N的反应活性顺序为:复合材料纳米铁改性凹凸棒土,且复合材料作用下NH_4~+-N的转化率低,几乎无NO_2~--N生成。DO、温度对复合材料去除地下水NO_3~--N的影响较大;而光照和黑暗环境下,地下水中NO_3~--N的去除率及NH_4~+-N、NO_2~--N的生成量均无明显差异。研究成果旨在为NO_3~--N污染地下水工程修复提供理论依据和技术支撑。

Study of removal of nitrate nitrogen from groundwater using modified attapulgite-Fe nano composite material

In this study, we synthesized modified attapulgite-Fe nano composite material(A-NZVI)using the liquid-phase reduction method, and investigated the stability of A-NZVI and changes of three kinds of nitrogen(NO₃^--N, NH₄⁺-N, and NO₂^--N)in the reaction process. We also analyzed the effects of groundwater environmental factors(dissolved oxygen, temperature, and light)on the removal of NO₃^--N with A-NZVI. In the simulation of groundwater environment, the three kinds of materials were ranked in the following descending order according to their reactivity in removing NO₃^--N: A-NZVI, nanoscale zero-valent iron, and modified attapulgite. The conversion rate of NH₄⁺-N was low, with nearly no NO₂^--N generated, when using A-NZVI. Dissolved oxygen and temperature had significant influence on the removal of NO₃^--N from groundwater with A-NZVI. When in the light and dark environment, the removal rate of NO₃^--N and the amounts of generated NH₄⁺-N and NO₂^--N had no significant difference. The findings of the study provided a theoretical basis and technical support for restoration projects for groundwater with NO₃^--N pollution.