纳米过氧化钙对地下水中硝基苯的类-Fenton降解效果

为了探究基于纳米过氧化钙（CaO₂）的类芬顿氧化技术（Modified Fenton，MF）修复污染地下水的可行性，本研究先对纳米CaO₂制备方法进行改进，制备出有效含量高达88.35%的纳米CaO₂粉末；其次，通过分析静态试验中反应体系的pH值、DO以及硝基苯浓度变化，探究纳米CaO₂降解硝基苯的过程和影响因素，确定了硝基苯的降解动力学和最佳反应条件；通过掩蔽实验探究不同自由基的作用效力；最后进行一维模拟柱动态模拟，综合分析评估纳米CaO₂去除硝基苯的机理和效果.结果表明：CaO₂投加量、EDTA-Fe²⁺浓度与硝基苯初始物质的量浓度满足48：8：1时降解效果最佳，其降解曲线符合一级动力学曲线，且反应过程中起主要降解作用的自由基是·OH，但降解效果会受到HCO₃^-、SO₄^2-、Ca²⁺、Mg²⁺等离子的影响；一维模拟柱的模拟结果表明，在存在适量铁的条件下，纳米CaO₂可以作为过氧化氢缓释剂，通过类芬顿催化产生自由基降解污染物，这说明纳米CaO₂在场地修复中具有较好的应用前景.

Effect of nano calcium peroxide on the fenton-like degradation of nitrobenzene in groundwater

To investigate the feasibility of using the modified fenton (MF) with nanometer calcium peroxide (nano-CaO₂) for the remediation of contaminated groundwater, this study firstly improved the method for preparation of the nano-CaO₂, and achieved the effective content of 88.35%. Then, through the evaluation of changes in pH, DO and nitrobenzene concentrations in a static test, the nano-CaO₂ based nitrobenzene degradation process and the influencing factors were investigated, and the kinetics and the best reaction conditions of the nitrobenzene degradation were also clarified. In addition, the validity of different free radicals was studied by the masking experiments. Finally, by performing the dynamic simulation in a one-dimensional simulation column, the mechanism and efficacy of the nano-CaO₂ based nitrobenzene removal were also accessed. The results showed that the degradation efficacy was best, when the concentration ratio of CaO₂, EDTA-Fe²⁺ and the nitrobenzene was 48:8:1, and the degradation curve fitted to the first-order kinetic curve. It was also demonstrated that the main degradation radical in the reaction process was ·OH, and the degradation efficiency was affected by HCO₃^-, SO₄^2-, Ca²⁺ and Mg²⁺ plasma. According to the simulation test in the one-dimensional simulation column, it was revealed that with existing proper amount of iron, nano-CaO₂ could be a sustained release agent of hydrogen peroxide, and correspondingly, free radical induced degradation would be enabled through Fenton-like catalytic reaction, which indicated nano-CaO₂ would have a good application prospect in site remediation.