基于含水层介质中铁的类Fenton技术去除地下水中硝基苯

Oxidation of nitrobenzene in groundwater by Fenton-like technology based on iron in aquifer materials

为了将Fenton氧化技术氧化能力强的优势引入到硝基苯污染地下水的原位化学修复中,通过实验模拟在地下环境温度为8-10℃、pH为中性条件下,以含水层介质中铁为催化剂的类Fenton技术去除地下水中硝基苯的过程,比较不同浸提剂对含水层介质中铁的浸提效果,并对氧化硝基苯的反应中自由基生成规律和催化氧化机理进行研究。研究结果表明：浸提剂强化了介质中各形态铁的释放,浸提作用存在滞后性,浸提36 h后铁在浸提液中浓度达到峰值;浸提剂DCB对介质中Fe3＋和Fe2＋的浸提效率最高,分别为62.92%和30.17%。催化氧化反应中硝基苯与H2O2的最佳摩尔比为1：200,该条件下硝基苯去除率最大为80.2%;催化氧化反应过程中HO.的变化可分为3个阶段,即0-30 min的快速生成阶段,30-120 min的生成速率降低阶段和120-240 min的稳定阶段。

Simulated experiments were conducted to investigate the oxidation of nitrobenzene（NB） in groundwater by a Fenton-like technology under the condition of neutral pH and 8-10 ℃ and to make a comparison of the extraction efficiency by different extraction agents.The mechanisms of catalytic oxidation reaction and the production rule of hydroxyl radical were both studied.The new technology combined iron extraction of aquifer materials which were found in a contaminated site in China with hydrogen peroxide catalytic oxidation.The experimental results indicate that extracting method can enhance iron extraction efficiency but has hysteresis property because the highest extraction efficiency occurs after 36 h.An extraction agent called DCB has the highest efficiency and the efficiencies of Fe3＋ and Fe2＋ are 62.92% and 30.17%,respectively.The highest removal efficiency can reach 80.2% as the mole ratio of NB to H2O2 is 1：200.The production rule of hydroxyl radical has three stages.In the first stage hydroxyl radical generates rapidly in 0-30 min,then decreased slowly between 30 and 120 min,and at last the generation maintains steady from 120 to 240 h.