Monitoring of the total carbon and nitrogen balance during the mineralization of nitrogen containing compounds by heat activated persulfate
Monitoring of the total carbon and nitrogen balance during the mineralization of nitrogen containing compounds by heat activated persulfate
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DOI：
10.1016/j.cej.2019.02.115
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发表时间：
2019-07
影响因子：
15.1
通讯作者：
D. Köster;M. Jochmann;H. Lutze;T. Schmidt
中科院分区：
文献类型：
--
作者：
D. Köster;M. Jochmann;H. Lutze;T. Schmidt
过氧二硫酸盐（S2 O 82 −）作为一种非选择性氧化有机污染物的试剂，广泛应用于环境修复和水处理。S2 O 82 −本身是一种强氧化剂，但通过热、紫外线辐射或金属催化剂活化会形成硫酸根（SO 4 radical dot−），从而提供更高的氧化电位和更快的反应动力学。许多有机污染物被硫酸根降解的机理已经研究得很好，但最终的矿化产物通常没有评估。已知含氮化合物根据其结构和反应条件产生不同的矿化产物。为了确定主要矿化产物，评价了两种测定氮质量平衡的方法。第一种方法是基于总有机碳（TOC）和总氮结合（TNb）的组合。第二种方法使用TOC和离子色谱（IC）的组合。基于TOC和TNb通过高温燃烧的评价被认为是显着偏置的测量铵浓度被低估的TNb测量在过二硫酸盐的存在下。采用TOC/TNb法，氧化后氮的回收率为83.2 ± 1.1%。基于TOC/IC的方法的总回收率为91.1 ± 1.4%，其中NO3−和NH 4+被确定为主要产物。基于IC测量提供的铵分数，可以校正TOC/TNb结果中铵的低估，从而获得95.9 ± 3.1%的回收率。所提出的方法适用于测定氮质量平衡在实验室规模的研究，以及监测矿化产品在现场应用。
Peroxydisulfate (S2O82−) is widely applied in environmental remediation and water treatment as an agent for the unselective oxidation of organic contaminants. S2O82−itself is a strong oxidation agent but activation by heat, UV radiation, or metal catalysts forms sulfate radicals (SO4radical dot−), which offer a higher oxidation potential and faster reaction kinetics. The mechanism of degradation for many organic contaminants by sulfate radicals is well studied, but the final mineralization products are not commonly evaluated. Nitrogen containing compounds are known to produce different mineralization products depending on their structure and the reaction conditions. For the identification of the main mineralization products, two approaches for the determination of nitrogen mass balances were evaluated. The first approach was based on a combination of total organic carbon (TOC), and total nitrogen bound (TNb). The second approach used a combination of TOC and ion chromatography (IC). The evaluation based on the TOC and TNb by high temperature combustion was found to be significantly biased as measured ammonium concentrations were underestimated by the TNb measurements in the presence of peroxydisulfate. With the TOC/TNb method, 83.2 ± 1.1% of the initial nitrogen could be recovered after the oxidation. The TOC/IC based approach led to an overall recovery of 91.1 ± 1.4%, where NO3−and NH4+were identified as the main products. Based on the fraction of ammonium provided by the IC measurements, the TOC/TNb based results could be corrected for the underestimation of ammonium which led to a recovery of 95.9 ± 3.1%. The presented methods are applicable for the determination of nitrogen mass balances in lab-scale studies, as well as for the monitoring of mineralization products in field applications.