Gaseous and Particulate Oxidized and Reduced Nitrogen Species in the Atmospheric Boundary Layer in Scandinavia in Spring     

Asgeir Sorteberg  Øystein Hov  Sverre Solberg  Kjetil Tørseth  Hans Areskoug  Martin Ferm  Kit Granby  Heikki Lättilä  Karin Persson  David Simpson 《Journal of Atmospheric Chemistry》1998,30(2):241-271

Observations of the concentration of several nitrogen containing compounds at five rural Scandinavian sites during March–June 1993 are reported. Total nitrate (NO ₃ ^- + HNO₃) and total ammonium (NH ₄ ⁺ + NH₃) were measured by denuder and filter pack. In general the methods agree well. At all sites the particulate fraction dominated, with the largest fraction of NO ₃ ^- and the lowest of NH ₄ ⁺ at the sites which were closest to the emission sources. The fraction of NO ₃ ^- of total nitrate increased with increasing NO₂ concentrations, indicating that the nighttime conversion of NO₂ to NO ₃ ^- is an important route of formation for NO ₃ ^- . A positive correlation was found between HNO₃ and O₃ in June at all sites, while no correlation was found early in the spring. Model calculations were made with a lagrangian boundary layer photooxidant model for the whole period, and compared to the measured concentrations. The calculated ratio between mean observed and modelled daily maximum concentrations of ozone over the measurement period were within +/–10% at all sites. The models ability to describe the daily ozone maximum concentration was satisfactory with an average deviation of 19–22% from the observed concentrations. HNO₃ was underestimated by over 50% at all sites except the one closest to the emission sources. The correlation between modelled and observed concentrations was generally best for the sites with shortest transport distance from the sources of emission.  相似文献   

混合表面活性剂存在下锰的高灵敏显色反应研究   总被引：2，自引：0，他引：2  

尹家元  杨光宇 《岩矿测试》1998,17(4):282-284

研究了碱性介质中,Ｍｎ（Ⅱ）被空气氧化生成Ｈ２ＭｎＯ３,然后在Ｈ３ＰＯ４介质中,Ｃｕ（Ⅱ）和阳离子型有机相／水相微乳液（ＣＴＭＡＢ／戊醇／正庚烷／水）的存在下,Ｍｎ（Ⅳ）与二安替比林对乙氧基苯基甲烷（ＤＡｐＥＭ）生成橙色产物,λｍａｘ为４５０ｎｍ,ε＝１．９５×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。Ｍｎ（Ⅱ）的质量浓度在０～３２０μｇ／Ｌ内符合比尔定律。方法用于合金中锰的测定,结果与标准值符合,５次测定结果的ＲＳＤ＜３％。  相似文献   

KBr-K₂SO₄-H₂O体系在318.15 K下的热力学性质和相平衡预测研究          下载免费PDF全文

符阳晓  桑世华  崔瑞芝 《盐湖研究》2022,30(4):72-82

本文采用电动势法对318.15 K下三元体系KBr-K₂SO₄-H₂O的热力学性质进行研究。首先,测定了KBr-H₂O溶液中KBr的电动势,线性回归出电极响应斜率κ和电极常数E⁰,结果表明实验所用离子选择性电极具有良好的能斯特响应。然后,对318.15 K下三元体系KBr-K₂SO₄-H₂O混合溶液中KBr的平均活度系数进行了研究,绘制了离子强度I及离子强度分数y_b与KBr的平均活度系数关系图,由图可得,当离子强度I一定,随着离子强度分数 y_b增大,KBr平均活度系数逐渐减小,且减小的趋势越来越大。当离子强度分数y_b是个定值时,KBr平均活度系数随着离子强度I的增大而减小。应用活度系数数据通过多元线性回归拟合出该温度条件下Pitzer模型混合离子作用参数θBr,SO₄和ψK,Br,SO₄,并计算了混合溶液中K₂SO₄的平均活度系数、渗透系数Φ,水活度a_w,超额吉布斯自由能GE。应用拟合的Pitzer混合离子相互作用参数和Pitzer模型计算了该三元体系在318.15 K下的溶解度数据,并对计算结果和其他温度下已经报道的KBr-K₂SO₄-H₂O三元体系的共饱和点处的溶解度数据进行比较,对比结果表明,溶解度计算结果可靠,拟合的离子相互作用参数具有较好的精度,可用于计算相关体系的热力学参数和相平衡的预测。  相似文献   

Distribution,Origin and Development Status of Underground Brine Resource along the Coast of Laizhou Bay,Shandong Province     

LI Shouping  MENG Ye 《《地质学报》英文版》2014,88(Z1):222-222

正The underground brine resource along the coast of Laizhou Bay is the world’s rare shallow underground brine resource,which occurs in the Laizhou city in the east,and extends to the coastal area of the Binzhou city in  相似文献   

不同条件下波吉卵囊藻对氨氮的吸收速率     

刘梅  黄翔鹄  李长玲  钱欣  黎家润 《广东海洋大学学报》2012,(1):29-34

在实验室条件下模拟多种氮源共存的虾池水环境,利用稳定同位素示踪剂,研究温度、光照、盐度、pH、藻浓度对波吉卵囊藻氨氮吸收速率的影响。结果表明:温度、光照和藻浓度对波吉卵囊藻氨氮吸收速率影响极显著(P<0.01)。当温度为20℃,照度为4 500 lx,藻浓度为5.5×105/mL,波吉卵囊藻对氨氮均有最大的吸收速率,分别为1.114、1.400、1.482μg g-1 h-1。单因素方差分析得出波吉卵囊藻吸收氨氮的最优组合为:温度20℃,照度4 500lx,盐度15,pH 7.5,藻浓度5.5×105/mL。可通过对环境因子的调控,提高波吉卵囊藻对水体中氨氮的吸收速率。  相似文献   

灼烧处理对纤蛇纹石反应活性的影响     

高雄  朱辰  赵良 《高校地质学报》2012,18(2):273

    使用可循环的NH4Cl 溶液作为中间媒介获取Mg2+用于CO2 矿物封存是一种新兴工艺,但是纤蛇纹石在NH4Cl 溶液中较 低的Mg2+浸出率却是这项工艺发展的瓶颈。针对这一问题,本文采用灼烧处理对纤蛇纹石进行改性。结果表明, 灼烧处理 可以有效改变纤蛇纹石中Mg2+反应活性。在600℃灼烧后,所得产物与NH4Cl 反应的转化率达到55.64%,比灼烧前提高了 约43%。600℃灼烧处理脱除了纤蛇纹石外羟基,增大了矿物的反应表面积和具反应活性的Mg2+的量,促进了其与NH4Cl 的 反应 ;脱除内羟基后,具反应活性Mg2+减少,与NH4Cl 反应的转化率降低。  相似文献   

四苯硼钠—季铵盐容量法快速测钾   总被引：4，自引：3，他引：1       下载免费PDF全文

冉广芬  马海州  孟瑞英  陈育刚 《盐湖研究》2009,17(2):39-42

用四苯硼钠—季铵盐容量法间接测定钾,并与四苯硼钠重量法进行比较。测定1%以上的钾含量时,相对误差<1%,平均回收率为99.52%,标准偏差分别为0.0082、0.0073,变异系数分别为0.82%、0.33%(RSD,n=7)。该方法操作简便、快速、准确,适用于含钾产品的中间控制分析及钾盐、卤水、盐化工产品、钾肥中钾的快速测定。  相似文献   

不同水生植物对湿地无机氮素去除效果的模拟   总被引：7，自引：1，他引：6  

万晓红  李旭东  王雨春  陆瑾  赵茵茵  刘玲花  周怀东 《湖泊科学》2008,20(3):327-333

分别以芦苇、花叶水葱和苦草构建成小规模人工湿地模拟系统,开展不同类型水生植物湿地中无机氮（硝态氮和铵态氮）去除效果的试验。试验结果表明：在分别以芦苇、花叶水葱和苦草构成的模拟湿地单元中,虽然氧化还原等环境条件呈现较大差异,但不同类型水生植物湿地单元的铵态氮和硝态氮的去除率并没有显著差别,这与以往关于不同类型水生植物对氮素去除贡献的认识有所不同;水生植物对模拟湿地体系中氮素的去除具有重要作用,在相对较低的氮负荷（NH4^＋-N约为2.85mg／L,NO3^-N约为1.07mg／L,相当于一般城市污染河流）条件下,有水生植物湿地单元中铵态氮和硝态氮的10d去除率分别在39.32％和21.91％以上,而无水生植物的空白湿地单元对铵态氮和硝态氮的10d去除率分别只有34.68％和13.86％;在提高模拟湿地体系水体氮（NH4^＋-N约为5.50mg／L,NO3^-N约为3.37mg／L,是一般城市污染程度的2倍）负荷条件下,有水生植物湿地单元中铵态氮和硝态氮的10d去除率分别大于或等于66.87％和78.92％以上,而无水生植物的空白湿地单元对铵态氮和硝态氮的10d去除率仅为40.62％和31.77％,为人工湿地对原污水或初沉池出水的处理提供了有力依据。试验结果还表明,水生植物能有效促进湿地的氮素转化过程,显著缩短无机氮素在湿地中的寄宿时间。  相似文献   

Suspended solids induce increasing microbial ammonium recycling along the river-estuary continuum of the Yangtze River     

Jingya Xue  Zhonghua Zhao  Xiaolong Yao  Weiting Liu  Lu Zhang 《水文研究》2021,35(8):e14345

Many large rivers worldwide are enriched with high levels of suspended solids (SS), which are known to be hotspots of many nitrogen (N) transformation processes (e.g., denitrification, nitrification). However, the influence of SS on microbial ammonium (NH₄⁺) recycling remains unclear. Water column NH₄⁺ regeneration rates (REGs) and potential uptake rates (U_pots) as well as community biological NH₄⁺ demand (CBAD) was measured in the river-estuary continuum of the third longest river in the world—Yangtze River, which has dramatic SS gradients. We found that REGs, U_pots, and CBAD all increased downriver, with higher REGs, U_pots, and CBAD in the estuary than in the river sections. The regeneration and uptake of NH₄⁺ were nearly balanced in the river sections, while the positive CBAD in the estuary indicated obvious NH₄⁺ demand of microbes. Concentrations of SS, which also control the content of chemical oxygen demand and particulate N, were the main factor influencing NH₄⁺ recycling rates and CBAD. SS-induced regenerated NH₄⁺ in the river-estuary continuum of Yangtze River was estimated to be 11.02 × 10⁸ kg N yr⁻¹ and accounted for about 14% of total N inputs, suggesting that regenerated NH₄⁺ is an important N source for microbes and may influence nutrient dynamics in lower coasts. To our knowledge, this is the first study to report NH₄⁺ recycling in Yangtze River with an emphasis on its influencing factors and contribution to N budgets.  相似文献   

自组装膜进样质谱系统及其在砂质沉积物异化硝酸盐还原研究中的应用     

谢成军  宋国栋  刘素美  唐继尧  张桂玲 《海洋学报》2020,42(2):22-29

沉积物中的异化硝酸盐还原过程对于海洋氮循环起着至关重要的作用。基于15N标记的培养技术是目前测定沉积物异化硝酸盐还原的主要手段。准确快速测定15N标记的产物(29N2、 30N2)是量化异化硝酸盐还原各个过程速率的关键。本研究自行组装膜进样质谱系统用于29N2和30N2的测定,对其测量条件进行了优化。结果表明,进样蠕动泵进样流速0.80 mL/min,进样时间3~3.5 min,恒温槽温度20~25℃,同时铜还原炉温度在300~600℃的条件下,^29N2/^28N2和^30N2/^28N2的测试精密度分别可以控制在0.1%和1%以内,比较适合29N2和30N2的测定。利用自组装的膜进样质谱系统结合15N标记的培养技术研究了青岛石老人沙滩沉积物中的异化硝酸盐还原过程。石老人沙滩沉积物不存在将硝酸盐完全还原为氮气好氧的反硝化。厌氧铵氧化、厌氧反硝化和异化硝酸盐还原为铵(Dissimilatory Nitrate Reduction to Ammonium,DNRA)的潜在速率(以湿沉积物N计)分别为(0.05±0.01) nmol/(cm^3·h),(2.32±0.21) nmol/(cm^3·h)和(1.02±0.15) nmol/(cm^3·h)。厌氧反硝化是硝酸盐异化还原主要的贡献者,其比例接近70%,其次是DNRA,比例可达30%,而厌氧铵氧化的贡献最低,仅为1%。在N2产生过程中,主要贡献者是反硝化,厌氧铵氧化的贡献仅为2%。  相似文献