PRB活性介质球磨硫铁矿去除硝基苯

采用机械化学法制备了球磨硫铁矿粉末（BMP），采用批次实验研究了BMP对硝基苯（NB）的还原性能，采用砂柱实验考察BMP用于填充可渗透反应屏障（PRB）以修复硝基苯污染地下水的可行性.X射线衍射（XRD）、扫描电子显微镜（SEM）、傅立叶变换红外光谱（FT-IR）和X射线光电子能谱（XPS）对BMP反应前后的形态、晶体结构和元素组成进行表征分析.结果表明，BMP可以有效地去除NB，去除率达98.8%，主要还原产物为苯胺（AN）.准一级动力学模型较好地拟合了NB的降解过程，降解动力学常数为59.03×10^-3min^-1.GC-MS分析未检出除AN外的其它污染物.砂柱实验结果表明，BMP-PRB可以连续高效去除模拟地下水中的NB，地下水成分保持稳定，急性毒性显著降低.表征分析表明，BMP对NB及其还原产物有一定的吸附作用.BMP表面持续产生具有还原性的Fe²⁺和S^2-等活性物质，可与NB的强吸电子基团硝基反应生成AN和Fe³⁺，而Fe³⁺氧化硫铁矿会产生Fe²⁺并促进Fe²⁺-Fe³⁺循环.

Removal of nitrobenzene by ball-milled pyrite as permeable reactive barrier active medium

Ball-milled pyrite (BMP) was prepared by mechanochemical method, and the reduction performance of BMP to nitrobenzene (NB) was studied by batch experiments. The sand column experiment was used to investigate the feasibility of using BMP to fill a permeable reaction barrier (PRB) to remediate nitrobenzene-contaminated groundwater. The morphology, crystal structure and elemental composition of BMP before and after reaction were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results showed that BMP can effectively remove NB, the removal rate of NB was 98.8%. The main reduction product of NB was aniline. The pseudo-first-order kinetic model fitted the degradation process of NB well, and the degradation kinetic constant was 59.03×10^-3min^-1. No contaminants other than aniline were detected by GC-MS analysis. The results of the sand column experiment showed that BMP-PRB can continuously and efficiently remove nitrobenzene from groundwater. The groundwater composition kept stable, and the acute toxicity was significantly reduced. Characterization analysis showed that BMP has a certain adsorption capacity on NB and the reduced product. On the surface of BMP, active substances such as Fe²⁺ and S^2- with reducibility were continuously produced, which could react with the strong electron-withdrawing nitro group of NB to generate AN and Fe³⁺. The pyrite can be oxidized by Fe³⁺ to produce Fe²⁺ and promote the Fe²⁺-Fe³⁺ cycle.