【作者】 韩莹；

【导师】 陈忠林；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2013， 博士

【摘要】 亚硝基二甲胺（NDMA）是亚硝胺类污染物的代表物质，对人类具有潜在致癌性，在原水和消毒后的出水中都曾被检出。常规的处理方法不能对其进行有效控制，于是需要强化处理技术对其进行去除。国内外研究者进行了吸附、生物处理、膜分离、高级氧化、加氢催化还原等技术处理NDMA的研究，但这些技术存在对其处理不彻底、反应时间长、能耗大、不易操作等问题。因此需要开发新的对NDMA有效的控制方法。本文首先对铁氧化物对NDMA的还原效能进行探究；在比较零价铁和零价锌还原NDMA的效能的基础上选取零价锌进行还原NDMA的反应，对该反应的速率、主要影响因素对该反应的影响进行考察并进行了理论解释，为更好地进行产物分析，建立了中间产物偏二甲肼（UDMH）的痕量检测方法，进行了该反应体系的产物分析和机理推断；为了进一步提高反应速率，研究了Cu2+结合零价铁（Fe/Cu2+）和零价锌（Zn/Cu2+）还原NDMA的反应，考察了Cu2+的投量对反应的影响，进行了该反应体系的产物分析和机理推断。首先探究了Fe2+结合一系列铁氧化物、磁铁矿、绿铁矿和NDMA的反应。结果表明Fe2+结合针铁矿、赤铁矿、纤铁矿和水铁矿，磁铁矿、Fe2+结合磁铁矿，绿铁矿均对NDMA没有明显的还原效果。加入Cu2+后绿铁矿对NDMA有明显的还原效果，但使用不同批次绿铁矿的反应体系间及平行样间对NDMA的去除效果相差较大。比较了零价铁和零价锌还原NDMA的效能，结果表明零价锌对NDMA的还原效果较好。采用零价锌还原NDMA，考察了反应速率，由结果可知，零价锌能够有效还原NDMA，溶液初始pH值为7.0时，反应分为停滞期和快速反应期，停滞期的数据符合零级反应动力学模型，快速反应期的数据符合准一级反应动力学模型。通过考察有无NDMA时锌离子的溶出和pH值的变化得出NDMA的投加对锌的腐蚀几乎没有影响。考察溶液初始pH值对反应的影响，得出较低的pH值有利于反应的进行。进行无氧和有氧条件下零价锌还原NDMA反应，发现反应前8h溶液中无氧比有氧有利于反应的进行，之后6h溶液中有氧比无氧有利于反应的进行。在以上的反应过程中通过对NDMA的还原规律、反应过程中pH值和溶出锌离子的变化规律的对比得到锌和NDMA的反应活性和锌的腐蚀速率是一致的，不同反应条件下对于NDMA的去除效果以及动力学的差别与可用的H+量有关。通过对各种反应条件下腐蚀情况的总结得出在有氧条件下对于氧的消耗形成钝化膜、局部酸化形成H+以及钝化膜的破裂是导致从停滞期到快速反应期转变的原因。建立了高效液相色谱对水中痕量UDMH的检测方法。采用4-硝基苯甲醛对UDMH进行衍生，并对色谱条件和衍生条件进行优化。该方法能够快速检测水中痕量的UDMH，检出限低、具有良好的线性关系。方法精密度和准确度高，检测模拟水样时的相对标准偏差≤1.69%，加标回收率为95.7%～102.7%。对零价锌还原NDMA进行产物分析得出零价锌还原NDMA生成UDMH和二甲胺（DMA）。UDMH是NDMA和DMA之间的中间产物，同时在零价锌还原NDMA和UDMH过程中有一些未测定的产物。基于反应现象、锌和NDMA的性质，反应机理被推断为催化加氢。进行了Cu2+存在下零价铁和零价锌还原NDMA的反应，考察了Cu2+浓度对Fe/Cu2+和Zn/Cu2+还原NDMA的效能和反应速率的影响，Fe/Cu2+和Zn/Cu2+还原NDMA的效果分别优于Fe(0)和Zn(0)还原NDMA的效果。通过对Fe/Cu2+和Zn/Cu2+还原NDMA体系进行产物分析得出Cu2+的存在未改变产物的类型，UDMH和DMA仍是这两种反应体系的产物，UDMH能被进一步还原为DMA，还有未测定产物的存在。基于反应现象及已有文献，这两种体系的反应机理被推断为催化加氢。通过理论计算和对反应后金属颗粒的表征得出Fe/Cu2+体系中起到促进还原NDMA作用的为Cu(OH)2，Zn/Cu2+体系中起到促进还原NDMA作用的为Cu2O和Cu(OH)2。本研究探究了铁氧化物和NDMA的反应，填补了NDMA自然衰减和在管网中衰减的数据空白。进行了零价锌以及Fe/Cu2+和Zn/Cu2+体系还原NDMA的系统研究，为进一步开发金属还原NDMA提供了数据支持。更多还原

【Abstract】 Nitrosodimethylamine (NDMA) is the representative of nitrosamines as the pollutants. It is potentially carcinogenic to humans, and has been detected in the raw water and the effluent after disinfection. Conventional treatment methods cannot treat NDMA effectively. Thus, the enhanced processing technologies are needed to remove NDMA. Domestic and foreign researchers conducted the studies on adsorption, biological treatment, membrane separation, advanced oxidation, catalytic reduction with hydrogen, et al. However, these technologies have many issues such as incomplete degradation, long reaction time, high energy consumption, complicate operation. Therefore, there is the need to develop new effective methods to treat NDMA.In this paper, the efficiencies of the reduction of NDMA with iron oxides were explored. The efficiencies of the reduction of NDMA with zero-valent zinc and zero-valent iron were compared. Zinc was chosen to reduce NDMA. The reaction rates were investigated, the effects of the main influencing factors on the reduction were examined, the theoretical explanations for the above phenomena were conducted. For the better product analysis, the detection method for the trace unsymmetrical dimethylhydrazine (UDMH) in water, which is the intermediates during the reduction of NDMA, was established. The products of the system were analyzed and the mechanisms were deduced. To further enhance the reaction rates, the reductions of NDMA with Cu2+and iron (Fe/Cu2+) and Cu2+and zinc(Zn/Cu2+) were studied, the effects of the Cu2+loading on the reduction of NDMA were examined, the products were analyzed and the mechanisms were deduced.First of all, the reactions of the Fe2+bound to the iron oxides with NDMA, magnetite with NDMA, green rust with NDMA were explored. The results showed that Fe2+bound to goethite, hematite, lepidocrocite and ferrihydrite, magnetite and Fe2+bound to magnetite, green rust had no obvious degradation of NDMA. After the addition of Cu2+, green rust can degrade NDMA significantly, however, there were considerable differences on the NDMA removal between the reaction systems using different batches of green rust and between parallel samples.The efficiencies of the reduction of NDMA with zero-valent iron and zero-valent zinc were compared, the results showed that zero-valent zinc was more reactive than iron on the reduction of NDMA. Zero-valent zinc was used to reduce NDMA. The reaction rates were examined. The results showed that the zero-valent zinc could degrade NDMA effectively, at initial pH7.0, the reaction was divided into the lag period and the rapid reaction period, the data of the lag period obeyed the zero-order kinetic model, the data of the rapid reaction period obeyed the pseudo-first-order kinetic model. By examining the dissolved zinc ions and the pH change with and without the addition of NDMA, it was found that the addition of NDMA had little effect on the zinc corrosion. The pH effect was examined. The low pH was found to facilitate the reaction. The reduction of NDMA with zinc in aerobic and anaerobic conditions were conducted, the anaerobic condition was good for the reduction in the first8h, the aerobic condition benefited the reduction in the following6h. After comparing the phenomena of the NDMA reduction, the pH changes and the dissolved zinc ion in the above reaction systems, the zinc reactivity on the NDMA reduction was found to be consistent with the zinc corrosion rates. The differences of the removal efficiencies and kinetics of the reduction of NDMA under the different reaction conditions were related to the available amount of the H+. Through the summary of the corrosion conditions of a variety of reaction conditions, the oxygen consumption forming the passive film, localized acidification forming H+and the breakdown of passive film were regarded as the reason of the transformation from the lag period to the rapid reaction period.A high performance liquid chromatography method was developed for the determination of trace unsymmetrical dimethylhydrazine (UDMH) in water.4-nitrobenzaldehyde was used for the derivatization of UDMH, the chromatographic conditions and the derivative conditions were optimized. The method is rapid in determination, and has a low detection limit, the good linear relationship, the high precision and accuracy of determining trace UDMH in water. For the simulated water sample, the relative standard deviation was equal to or less than1.69%, the recovery of standard addition was95.7%~102.7%. Through the products analysis, we found that UDMH and DMA were formed during the reduction of NDMA. UDMH was intermediates between NDMA and DMA, some unmeasured products also existed in the process of reductions of NDMA and UDMH with zero-valent zinc. Catalytic hydrogenation was deduced as the mechanism based on the reaction phenomenon and the characters of the zero-valent zinc and NDMA.The reductions of NDMA with zero-valent iron and zinc in the presence of Cu2+ were conducted. The effect of Cu2+concentration on the efficiencies and the reaction rates of reduction of NDMA with Fe/Cu2+and Zn/Cu2+systems were studied. The Fe/Cu2+and Zn/Cu2+systems were more reactive than Fe(0) and Zn(0) systems, respectively. Through the products analysis, it was found that the presence of Cu2+did not change the type of the products. UDMH and DMA still were the products of the two reaction system. UDMH can be further reduced to DMA. There are other unmeasured products existing in the reaction system. The mechanism of the two reaction systems was deduced to be catalytic hydrogenation based on the reaction phenomenon and existing literatures. Basing on the theory calculation and the characterizations of the metal powders after reaction, Cu(OH)2was found to be the substance that enhanced the reduction of NDMA in the Fe/Cu2+system, Cu2O and Cu(OH)2were found to promote reduction of NDMA in the Zn/Cu2+system.In this research, the reaction of the iron oxides and NDMA was explored, which can fill the data gap in the natural attenuation and the attenuation in the water distribution system. The systematic studies were conducted on the reduction of NDMA with zero-valent zinc, Fe/Cu2+and Zn/Cu2+. The studies can supply the data supporting the further development of the reduction of NDMA with metals.更多还原