硫化纳米铁反应带修复硝基苯污染地下水

采用前置硫化合成法制备硫化纳米铁（S-NZVI）并进行表征，采用模拟砂柱创建S-NZVI原位反应带，研究其对硝基苯（NB）污染地下水的修复效能.X射线衍射（XRD）、X射线光电子能谱（XPS）、透射电子显微镜（TEM）表征结果表明，S-NZVI是以Fe（0）为核心，硫铁化合物为外壳的颗粒，可以有效抑制S-NZVI颗粒的团聚，具有较好的分散性.与NZVI相比，S-NZVI对NB的去除效率更高，最高去除率可达99.65%，在砂柱中具有更强的穿透能力.S-NZVI对NB的去除过程符合准一级动力学模式.S-NZVI对NB的去除机理是先将NB快速吸附于表面，然后再进一步通过化学还原降解，因此NB去除较快而苯胺生成较慢.S-NZVI反应带对NB泄露区的削减幅度较大，增加单井S-NZVI注入量和增加注入井均可提高修复效果，7d内NB累计去除率最高达87.43%，但前2d出水NB浓度仍然较高；S-NZVI反应带对NB传输区具有较好的修复效果，增加注入井比增加单井S-NZVI注入量具有更好的持续性和更高的NB去除率，7d内NB累计去除率最高达99.90%.

Remediation of nitrobenzene contaminated groundwater by S-NZVI reaction zone

Sulfidated-nanoscale zerovalent iron (S-NZVI) was prepared by pre-sulfide synthesis and characterized. The S-NZVI reaction zone was established in sand columns to study the remediation efficiency of nitrobenzene contaminated groundwater. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) characterization tests showed that ferrous sulfide coating on the surface of Fe(0), which could inhibit the aggregation of S-NZVI particles, thus showed better dispersibility. Compared with NZVI, S-NZVI has higher degradation efficiency for NB, and the highest degradation efficiency was 99.65%. The degradation process of NB by S-NZVI conformed pseudo-first-order kinetics. It has stronger penetrating ability in sand column. The removal mechanism of S-NZVI on NB was that NB was quickly adsorbed on the surface and then further degraded by chemical reduction, so NB removal was faster and aniline formatioon was slower. The S-NZVI reaction zone had a large reduction of NB in the leakage zone. Increasing the single-well S-NZVI injection volume and adding injection well both improved the remediation efficiency. The cumulative removal efficiency of NB in the 7days was up to 87.43%, but the NB concentration in the first 2d was still high. The S-NZVI reaction zone showed better remediation effect in the transmission zone. Adding injection well showed better persistence and NB removal rate than increasing S-NZVI injection volume in the single well, and the cumulative removal efficiency of NB in the 7days was up to 99.90%.