球磨硫铁矿-过硫酸盐联合降解水中硝基苯和苯胺

采用湿式球磨法制备微纳级硫铁矿粉末,研究了球磨硫铁矿(BMP)和过硫酸盐(PS)联合处理对水环境中硝基苯(NB)及其还原产物苯胺(AN)的降解效果,分别考察了BMP投加量、溶液初始pH和PS投加量对NB和AN降解的影响,采用TEM、XRD、FT-IR和XPS对反应前后的BMP进行了表征,分析了反应溶液中TOC和主要离子的变化,采用响应面法设计多因素实验,对反应条件进行了拟合和优化。结果表明,NB浓度与BMP投加量呈负相关关系,AN浓度与PS投加量呈负相关关系,pH在酸性和中性条件下NB和AN降解效果好。当BMP投加量为5 g·L⁻¹时,NB去除率达99%;当PS投加量为2.5 g·L⁻¹时,AN浓度低于1 mg·L⁻¹。BMP/PS联合处理可以高效降解NB并消减还原产物AN。采用二次多项式和逐步回归法拟合NB去除率、AN浓度和反应条件之间的关系,模拟值与验证实验结果相近,模型精度较好。表征结果表明,BMP单独处理时Fe(Ⅱ)和S²⁻作为活性物质与NB反应,生成${rm{SO}}_3^{2 - }$和Fe(Ⅲ)以及中间产物AN;联合处理中BMP中的Fe(Ⅱ)活化PS生成具有强氧化性的${rm{SO}}_4^{ - cdot }$和HO·,其可与AN反应生成${rm{SO}}_4^{2 - }$和单质S,Fe(Ⅱ)和Fe(Ⅲ)与水中的OH⁻或O₂反应,生成铁氧化物。BMP/PS联合处理可以快速高效彻底降解NB,在含NB废水处理或NB污染地下水修复中具有应用潜力。

Degradation of nitrobenzene and aniline in water with ball milled pyrite and persulfate

In this study, the micro-nano level pyrite powder (BMP) was prepared by wet spheroidal grinding. Then BMP was used to degrade nitrobenzene (NB) and its reduction product of aniline (AN) in water with combination of persulfate (PS). The effects of BMP dosage, initial pH of solution, and PS dosage on NB and AN degradation were investigated. The TEM, XRD, FT-IR and XPS were used to characterize the properties of BMP before and after reaction, and the changes of TOC and main anions in the reaction solution were analyzed. The response surface method was used to design multi-factor experiment, and the reaction conditions were fitted and optimized. The results showed that the NB concentration was negatively correlated with the BMP dosage, and the AN concentration was negatively correlated with the PS dosage. At the initial acidic and neutral pHs, the best degradation effects of NB and AN occurred. When the BMP dosage was 5 g·L−1, the removal rate of NB reached 99%. When the PS dosage was 2.5 g·L−1, the concentration of AN was less than 1 g·L−1. The joint treatment with ball-milled BMP and PS could efficiently degrade NB and eliminate its main reduction product AN. The relationship between NB removal rate and reaction conditions, AN concentration and reaction conditions were fitted using the quadratic polynomial and the stepwise regression methods. The simulated values were close to the verification experiment results, so the model accuracy was good. Characterization results showed that Fe(Ⅱ) and S2− as active substances reacted with NB to produce ${rm{SO}}_3^{2 - }$, Fe(Ⅲ) and intermediate product AN when BMP was used alone; in the joint treatment, Fe(Ⅱ) in BMP activated PS to form strong oxidizing ${rm{SO}}_4^{ - cdot }$ and HO·, which reacted with AN to form ${rm{SO}}_4^{2 - }$ and elemental S. In addition, Fe (Ⅱ) and Fe (Ⅲ) reacted with OH− or O2 in water to form iron oxide. The joint treatment of BMP/PS can degrade NB quickly, efficiently and completely. It has application potential for treating wastewater containing NB or remediating NB-contaminated groundwater.