蒙脱土层间限域nZVI改性凝胶修复土壤重金属污染机理及其环境效应研究

近年来，纳米零价铁（nZVI）技术作为土壤重金属污染修复的一种有效方法得到广泛应用。目前，在稳定化载体上全面构建高分散稳定的nZVI活性组分，对于土壤重金属的高效修复具有重要意义。本研究从优化制备蒙脱土层间限域nZVI出发，以具有三维交联网络结构的羧基改性生物质水凝胶为功能载体，研究构建集高活性、抗氧化、铁离子靶向缓控释及重金属长效稳定性能于一体的蒙脱土层间限域nZVI改性凝胶（nZVI-MMT@RH），从根本上解决了单一nZVI易团聚氧化、反应活性低、反应速率慢的问题，而且可通过其对铁离子靶向释放过程的有效调控作用，实现土壤重金属污染风险的长效阻控。通过研究nZVI-MMT@RH微观结构与重金属稳定性能之间的内在规律，深入探讨其对土壤重金属的稳定化机理，系统揭示nZVI-MMT@RH修复土壤的环境效应及其影响机理，以期为该技术在重金属污染土壤修复中的推广提供理论依据和实践基础。

Recently, the nZVI technology has been widely used as an effective method for remediation of heavy metal contaminated soil. At present, the preparation of highly uniformly stable nZVI active component supported on the stabilizing carrier is of great significance in highly efficient remediation of heavy metals in soil. The project aimed at constructing of nZVI confined in montmorillonite layers-modified hydrogel composite material (nZVI-MMT@RH) with the characteristics of high activity, antioxidation, slow and controlled release of iron ions and heavy metal long-term stability properties, which started from the preparation of nZVI confined in montmorillonite layers followed by immobilization of carboxyl modified biomass hydrogel with three-dimensional crosslinking structure. The synthesis of nZVI-MMT@RH not only can solve some problems of agglomeration, oxidization, low reactive activity and rate for original nZVI, but also can control the target release process of iron ions, which is favorable to the effective control of the soil contamination risk. The relation between the physical characters of nZVI-MMT@RH and the stability of heavy metals are expounded on in the research. Furthermore, the stabilization mechanism of heavy metal in the soil, and the environmental effects of soil remediated by nZVI-MMT@RH and its influence mechanism are discussed. Related research results provide the theoretical and practical basis for soil heavy metals pollution remediation.