纳米零价铁（NZVI）已被广泛应用于地下水中原位修复重金属和有机污染物。然而，水中腐蚀和反应过程将使NZVI表面形成钝化层，严重限制NZVI的修复效能和电子利用率。本项目拟开发基于核壳结构的原位抗钝化技术。通过在NZVI表面包覆铝基薄膜，聚丙烯酸可被富集在表面，形成可渗透的铝基复合膜（AH）。AH可改变NZVI表面微观环境，其丰富的羧基能有效抑制氢氧化物沉积，进而影响钝化和反应过程。首先，建立制备调控体系，分析包覆层化学组分，优化核壳结构NZVI的修复效能。接着，针对地下水修复中好氧腐蚀、还原六价铬和活化过硫酸盐等典型钝化过程，研究AH在不同反应中对钝化层形成速率、化学组分和配位结构的影响，阐释抗钝化机理。然后，研究水质环境对抗钝化的影响机制。最后，构建可渗透反应区域，研究AH抗钝化行为的空间分布特征。项目成果将促进NZVI原位抗钝化技术的发展，推动NZVI技术在我国地下水修复中的应用。

Nanoscale zero-valent iron (NZVI) has been extensively used for in-situ groundwater remediation. However, a passivation layer will form on the surface of NZVI particles during the process of aqueous corrosion and contaminant removal. The passivation layer seriously limits the efficiencies of remediation and electron utilization of NZVI. This study is to modify NZVI with a core-shell structure for in-situ anti-passivation. By coating an aluminum-based shell, polyacrylic acid can be anchored on the NZVI surface to form an aluminum-based hybrid shell (AH). The AH shell with abundant carboxyl groups will change the vicinity environment on the particle surface. The abundant carboxyl groups of polyacrylic acid can effectively inhibit the formation of hydroxide precipitates and, therefore, influence the passivation and reaction process. The main contents of this study are: to control the properties of the AH shell and optimize the remediation performance of the coated NZVI; to investigate the effect of the AH shell on the representative passivation process, i.e., aerobic corrosion, Cr(VI) reduction and persulfate activation; to elucidate the mechanisms of anti-passivation with the AH shell by analyzing the formation rate, chemical compositions, and coordination structures of the passivation layer during the reactions; to build a permeable reactive zone and study the spatial characteristics of the anti-passivation behavior with the AH shell. The study will advance the development of in-situ anti-passivation techniques for NZVI, and promote the application of NZVI techniques for groundwater remediation in China.