【作者】 田晓雷；

【导师】 陈莹；

【作者基本信息】 长安大学 ， 建筑与土木工程（专业学位）， 2017， 硕士

【摘要】 氧化亚氮(Nitrous oxide, N2O)是大气中存在的一种重要温室气体,与二氧化碳(Carbondioxide,CO2)和甲烷(Methane,CH4)并称世界三大温室气体。污水生物处理过程是N2O的一个重要来源。羟胺(Hydroxylamine,NH2OH)氧化过程、氨氧化细菌(Ammonia oxidizing bacteria, AOB)反硝化过程和异养反硝化过程均会生成N2O。作为硝化过程中的一种中间产物,NH2OH与N2O的产生直接相关,然而由于其具有极强的反应活性,易于与多种物质发生,致使污水生物处理过程中产生的NH2OH难以测定,NH2OH与N2O产生量之间的定量关系及其对N2O产生过程的影响尚未明确。本课题采用N2O微电极法和硫酸铁铵-邻菲罗啉分光光度法测定污水生物处理过程中的NH2OH。研究了亚硝态氮(NO2-)对N2O微电极法NH2OH测定结果的干扰及其消除方法和硝态氮(NO3-)、亚硝态氮(NO2-)、正磷酸根(PO43-)、钙离子(Ca2+)及污水生物处理过程常见的微量元素对硫酸铁铵-邻菲罗啉法NH2OH测定结果的影响。针对PO43-对硫酸铁铵-邻菲罗啉法NH2OH测定结果的干扰,建立了 一种数值方法消除此种干扰。通过将硫酸铁铵-邻菲罗啉法应用于短程硝化SBR反应器中NH2OH的测定,得到了不同进水氨氮浓度条件下,NH2OH与N2O生成量之间的定量关系。本研究主要结论如下:(1)采用N2O微电极法测定NH2OH-N浓度的研究结果表明,NO2-的存在会干扰该方法的测定结果。当样品中NO2--N<10.0mg/L时,采用加入一定量磺胺的方法可以消除NO2-对测定结果的干扰。在采用该方法测定污水生物处理过程的NH2OH时,该方法的测定浓度下限为0.1mg NH2OH-N/L。(2)采用硫酸铁铵-邻菲罗啉法测定样品中的NH2OH-N浓度的研究结果表明,在无干扰条件下,样品中的NH2OH-N浓度与样品吸光度呈明显线性关系。不同干扰物质对该方法的影响结果和影响程度不尽相同。(3) NO3-对硫酸铁铵-邻菲罗啉法测定结果无影响。NO2-和PO43-在不同条件下对硫酸铁铵-邻菲罗啉法的测定结果产生的影响不同。当样品NO2--N浓度>15.0 mg/L时,NO2-对硫酸铁铵-邻菲罗啉法的测定结果会产生严重干扰,使测定结果偏小,且无有效手段消除此种干扰;当NO2--N浓度≤15.0 mg/L时,对硫酸铁铵-邻菲罗啉法的测定结果不会产生明显干扰,但会减小硫酸铁铵-邻菲罗啉法的测定范围;当样品中的NH2OH-N浓度>0.1 mg/L时,PO43-不会对硫酸铁铵-邻菲罗啉法的测定结果产生干扰。然而当样品中的NH2OH-N浓度<0.1 mg/L时,PO43-对硫酸铁铵-邻菲罗啉法的测定结果会产生严重干扰,使测定结果偏小。通过采用本研究建立的数值方法可在一定程度上减轻此种影响,保证测定结果的准确性。当样品中存在PO43-时,硫酸铁铵-邻菲罗啉法测定范围将由0.02～0.8 mg NH2OH-N/L缩小至0.05～0.8 mg NH2OH-N/L。(4)当样品中的Ca2+浓度≤8.0mg/L时,Ca2+不会对硫酸铁铵-邻菲罗啉法的测定结果产生干扰,当Ca2+浓度>8.0mg/L时,Ca2+对硫酸铁铵-邻菲罗啉法的测定结果会产生明显干扰。污水生物处理过程常见的微量元素不会对硫酸铁铵-邻菲罗啉法的测定结果产生干扰。(5)当进水氨氮浓度分别为50 mg/L和70 mg/L时,反应器内溶解态N2O浓度的峰值分别为0.11 mg/L和0.52mg/L。在此过程中,NH2OH-N的浓度保持稳定,约为0.06 mg/L左右。根据对不同进水氨氮浓度下反应器中NH2OH-N浓度的监测结果,在NH2OH氧化过程中,NH2OH-N的半饱和常数值应很小,如0.05 mg NH2OH-N/L。硫酸铁铵—邻菲罗啉分光光度法可以用于测定污水生物处理系统的NH2OH浓度,本研究的开展对于揭示硝化过程中NH2OH与N2O产生量之间的定量关系,明晰好氧条件下N2O的生成机制提供了重要的方法基础。更多还原

【Abstract】 Nitrous oxide (N2O) is an important greenhouse gas in the atmosphere, which is called the third major greenhouse gases with carbon dioxide (CO2) and methane (CH4) of the world. The biological treatment of sewage is an important source of N2O,Hydroxylamine (NH2OH) oxidation process, mmonia oxidizing bacteria (AOB)denitrification process and heterotrophic denitrification process can produce N2O. As an intermediate producing in nitrification, NH2OH is directly related to the production of N2O. As NH2OH is an extremely reactvie matter and it can be reacted with many substances, determination of NH2OH in biological wastewater treatment process is not an easy task. Furthermore, the quantitative relationship between NH2OH and the amount of N2O production and effects of NH2OH on the N2O production process have not been cleared.In this study, N2O microelectrode and ammonium ferric sulfate-1, 10 phenanthroline spectrophotometric method were used to determine NH2OH in biological wastewater treatment process. Interference of nitrite nitrogen (NO2-) on N2O microelectrode method and the elimination method was studied. Besdies, the effects of nitrate nitrogen (NO3-)、nitrite nitrogen (NO2-)、orthophosphate (PO43-)、Calcium Ion (Ca2+) and trace elements in biological wastewater treatment processes on the spectrophotometric method was also studied. As PO43- had severe interference on the spectrophotometric method, a numerical method was established for eliminating the interference. The quantative relationships bwtween NH2OH and N2O production under different influent ammonia nitrogen(NH4+-N) concentraitons were obtained by applying the 1, 10 phenanthroline spectrophotometric method to the determination of NH2OH concentations in a short-cut nitrification SBR process.The following conclusions were drawn:(1) The presence of NO2 -N interfered with the determination of NH2OH-N by the N2O microelectrode mothod. When NO2--N concentration was lower than 10.0mg/L in the sample, the interference of N2--N on the method could be eliminated by addition of certain amount of sulfonamide. When the method was used to measure NH2OH in the biological wastewater treatment processes, the lower limit of detection was 0.1 mg NH2OH-N/L.(2) In determination of NH2OH-N by the spectrophotometric method, NH2OH-N concentration in the samples was linearly correlated with the absorbance of the samples without interference. The effects of different interfering substances on the method were not same.(3) NO3- did not interfere with the determination of NH2OH-N by the spectrophotometric method. NO2- and PO43- had different effects on the determination of NH2OH-N by the spectrophotometric method. When the concentration of NO2--N in samples was higher than 15.0 mg/L,the determination NH2OH-N by the spectrophotometric method was interfered severely by NO2--N which could make the determination results of NH2OH-N smaller, and there was no effective method for eliminating the interference. When concentration of NO2--N in samples was lower than 15.0 mg/L, NO2--N did not interfered with the determination of NH2OH-N by the spectrophotometric method, however, it would reduce the determination range of the spectrophotometric method. When concentration of NH2OH-N in samples was higher than 0.1 mg/L, PO43- did not interfere with the determination of NH2OH-N by the spectrophotometric method. When concentration of NH2OH-N in samples was lower than 0.1 mg/L, the determination NH2OH-N by the spectrophotometric method was interfered severely by PO43- which could make the determination results of NH2OH-N smaller. Numerical method established in this study could alleviate the interferences causing by PO43+ in certain extent and ensure the accuracy of the determination results of the spectrophotometric method. When PO43- presented in samples, the determination range of the spectrophotometric method was varied from 0.02 -0.8 mg NH2OH-N/L to 0.05～0.8mg NH2OH-N/L(4) Ca2+ did not interfere with the determination of NH2OH-N by the spectrophotometric method when the concentration of Ca2+ in sample was lower than 8.0 mg/L. When the concentration of Ca2+ in samples was higher than 8.0 mg/L, the determination NH2OH-N by the spectrophotometric method was interfered severely by Ca2+. Common trace elements in biological wastewater treatment processes did not interfere with the determination of NH2OH-N by the spectrophotometric method.(5) The maximum concentrations of dissolved N2O-N in the reactor were 0.11 mg/L and 0.52 mg/L respectively when ammonia concentrations in the influent were 50 mg/L and 70 mg/L. However, NH2OH-N fluctuated around 0.06 mg/L,and didn’t vary with the increasing of the influent NH4+-N concentration. According to the determination results of NH2OH-N concentrations, the half-saturation of NH2OH in the bio-chemical conversion process of NH2OH-N to NO2 -N was very small, and 0.05 mg NH2OH-N/L was reasonable.Ammonium ferric sulfate-1, 10 phenanthroline spectrophotometric method could be used for determination of NH2OH in biological wastewater treatment process. An important method was provided in this study, and it was helpful to acertain the the quantitative relationship between NH2OH and N2O production in nitrification process and understand the mechanism of N2O formation under aerobic conditions.更多还原