利用傅立叶变换红外光谱法检测一氧化氮纯气中的二氧化氮杂质

本文利用傅立叶变换红外光谱法检测一氧化氮纯气中的二氧化氮杂质。利用恒定条件进样和双点法校准进行定量分析,并对分析结果进行了不确定度评价。该方法的建立为一氧化氮纯气中二氧化氮的定性和定量分析提供了一个全新的途径。     

氮氧化物的制备、性质和应用

介绍了一氧化二氮、一氧化氮、三氧化二氮、二氧化氮、四氧化二氮、五氧化二氮的制备方法、性质和应用等     

氮氧化物的制备,性质和应用

介绍了一氧化二氮、一氧化氮、三氧化二氮、二氧化氮、四氧化二氮、五氧化二氮的制备方法、性质和应用等。     

NOx分析仪转化效率的统计计算方法

为了解决氮氧化物(NOx)分析仪转化炉转化效率的检测问题,对现有氮氧化物转化效率的计算模型进行了定量分析,结合计量工作中误差的含义,定义了氮氧化物分析仪检测过程中二氧化氮转化误差和一氧化氮检测误差两个概念;介绍了氮氧化物分析仪的非分光红外法检测原理和转化效率检测的必要性,采用臭氧发生器对氮氧化物分析仪进行转化效率检测,提出了基于二氧化氮转化误差和一氧化氮检测误差的转化效率二阶次计算模型,利用逐步回归原理确定模型中的自变量并进行参数估计。研究结果表明,相比于氮氧化物分析仪内嵌的计算模型和一阶次计算模型,本文提出的二阶次计算模型拟合方程的多重可决系数靠近1的程度平均提升了96.8%和51.5%,残差平方和平均降低了85.1%和31.7%,为提升氮氧化物分析仪的检测准确性提供技术支撑。     

安全监测设备校准用标准气体质量安全风险研究

对市场上流通的部分氮中一氧化氮、氮中二氧化氮、氮中硫化氢三类安全监测设备校准用气体标准物质进行采样,并使用一级标准物质进行标称值的检测和比对.对测试过程进行了不确定度评定,通过显著性分析来确定市售二级标准物质的标称值与实测值之间是否有显著性差异,并对该结果可能产生的事故风险进行了评估.从结果来看,标称值不准确的气体标准物质在市场流通会对生产活动造成一定的风险,需要有关监管部门加大重视力度.     

用黄磷水乳液清除烟道气中氮氧化物污染物的研究

本文报道了一种治理工业烟道气中氮氧化物的新方法，利用黄磷与高温烟道气中的氧作用所生的高活性的原子氧和臭氧化物清除剂，能有效地将烟道气中不溶于水泊一氧化氮化为易溶于水的二氧化氮，后者进一步与烟道气中二氧化硫溶于水形成的亚硫酸盐生成氮硫化物而被除去，本文还对影响一氧化氮清除的有关因素进行了讨论。实验表明提高磷在水溶液中的分散程度，控制反应温度和溶液酸碱度，以及烟道气流速等是提高一氧化氮吸收率的关键。     

氨气吸收液

重氮拷贝中常用氨水产生氨气或直接使用气态的氨气作为显影剂。氨气是一种具有刺激性气味的气体,长时间处于含有氨气的环境中,会对身体健康产生不良影响。为防止重氮拷贝过程中氨气的泄漏,重氮拷贝机在结构设计上常采取两种措施:一、对机器内氨气系统的零部件尽可能地采取密闭措施;二、对显影后的剩余氨气进行化学吸收,也就是使用化学方法除去剩余的氨气,使其不至于散发到空气中。常用的方法是     

二氧化氮转换效率测试及影响因素分析

二氧化氮转换效率偏低，会导致分析仪测试空气中的二氧化氮浓度偏低，发布的监测结果也会偏低。因此，二氧化氮转换效率的准确测量，为环境空气质量的准确评价提供了技术保障。该文对两种二氧化氮转换效率的测试方法进行了探讨，选用不同厂家、不同浓度的气体标准物质对两种不同催化剂的转换器进行测试，探讨了影响二氧化氮转换效率测试结果的可能因素及测试过程的注意事项，为相关使用方提供有益参考。     

氮中二氧化氮气体标准物质的研制

阐述了氮中二氧化氮气体标准物质的制备过程,该标准物质采用了GB/T 5274. 1—2018《气体分析校准用混合气体的制备第1部分:称量法制备一级混合气体》所规定的方法制备。产品采用ABB光谱吸收仪进行分析方法验证,并对其稳定性、均匀性进行考察。研究结果表明,使用特殊的气瓶内壁处理技术,能有效的解决气瓶吸附问题,在该标准物质氮中二氧化氮(50. 0～700)×10-6(摩尔分数)配制浓度范围内,当k=2时,扩展不确定度为2%,有效期1 a。     

电子鼻的混合气体分类研究

针对空气污染物氨气、乙醇、氨气乙醇混合气体,搭建在线检测电子鼻系统.采用不同的特征提取方法得出特征,并利用主成分分析(PCA)和线性判别式分析(LDA)做类别区分.结果显示,利用传感器响应最大值特征和LDA能更好地区分三类气体.利用最大响应值特征,采用多层感知器(MLP)神经网络和粒子群(POS)优化的支持向量机(SVM)对110个测试样本分类.结果显示,MLP神经网络的正确率为70%,POS优化的SVM正确率为96.364 0%.最后,根据Loadings分析,剔除了TGS2602,MQ138,MQ3传感器,优化了传感器阵列.结果表明,该在线电子鼻系统能够应用到这三类空气污染物分类.     

水热法制备氧化铬及其常温低浓度一氧化氮催化性能

以十六烷基三甲基溴化铵(CTAB)为模板剂, 氨水为沉淀剂, 通过水热法并焙烧处理合成氧化铬催化剂。采用X射线衍射分析(XRD)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)和透射电镜(TEM)等技术对催化剂的物化性质进行了表征, 并考察常温不同NO初始浓度下氧化铬催化剂的NO氧化性能。结果表明: 在空速为60000 mL/(g·h)和NO浓度为1×10^-6的条件下, 100℃水热温度制备的Cr-100催化剂表现出最优的性能, 常温下NO消除率高达90%以上并保持120 h, 其优异的常温催化性能与催化剂表面较高的Cr⁶⁺/Cr³⁺摩尔比有关。研究结果表明: 催化剂的失活主要是由于硝酸根在催化剂表面的累积而导致催化剂活性中心被覆盖, 低浓度下能减缓硝酸根的积累。     

On-Line Analysis of Stable Isotopes of Nitrogen in NH(3), NO, and NO(2) at Natural Abundance Levels

Methods were developed for the on-line analysis of stable isotopes of nitrogen (at natural abundance levels) in NH(3), NO and NO(2) in order to study the contribution of these trace gases to nitrogen cycling in ecosystems. Standard methods for the combustion of organic substances to N(2) (for the determination of the (15)N/(14)N ratios by mass spectrometry) failed to satisfactorily oxidize or reduce the respective trace gases. The following oxidation or reduction techniques ensured quantitative conversion of the trace gases to N(2) and analytical precision close to the internal precision of the instrument (precision ±0.15‰): (1) oxidation of NH(3) to N(2) at 1150 °C on a NiO surface (which needs a reoxidation before each NH(3) analysis; measuring range 11.7-58.8 nmol of NH(3), precision ±0.30‰); (2) reduction of NO to N(2) at 1150 °C on a Ni surface (measuring range 33.3-133.3 nmol of NO, precision ±0.28‰); (3) reduction of NO(2) to form NO at 420 °C on a Mo surface followed by further treatment as for NO (measuring range 26.0-129.9 nmol of NO(2), precision ±0.90‰). This last technique was developed due to the poor chromatographic properties of NO(2).     

用傅立叶变换红外光谱法检测气体中微量乙硼烷

利用配备长光程气体池的傅立叶变换红外光谱仪对气体中微量乙硼烷进行了定量分析。在恒定实验条件下进样,分辨率为4 cm~(-1),扫描8次,可以得到理想的分析结果。定量分析结果表明,该方法重复性良好(相对标准偏差0.5%),在0~100×10~(-6)摩尔分数范围内线性良好(R~2=0.9996),扩展不确定度小(4%),可用于气体中微量乙硼烷的定量分析。     

Photocatalytic reduction of NO with NH3 using Si-doped TiO2 prepared by hydrothermal method

A series of Si-doped TiO2 (Si/TiO2) photocatalysts supported on woven glass fabric were prepared by hydrothermal method for photocatalytic reduction of NO with NH3. The photocatalytic activity tests were carried out in a continuous Pyrex reactor with the flow rate of 2000mL/min under UV irradiation (luminous flux: 1.1x10(4)lm, irradiated catalyst area: 160cm2). The photocatalysts were characterized by X-ray diffraction (XRD), BET, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectrophotometer, transmission electron microscopy (TEM), photoluminescence (PL) and temperature-programmed desorption (TPD). The experiment results showed that NO conversion on Si/TiO2 at 323K could exceed 60%, which was about 50% higher than that on Degussa P25 and pure TiO2. With the doping of Si, photocatalysts with smaller crystal size, larger surface area and larger pore volume were obtained. It was also found that Ti-O-Si bands were formed on the surface of Si/TiO2 and that the surface hydroxyl concentration was greatly increased. As a result, total acidity and NH3 chemisorption amount were enhanced for Si/TiO2 leading to its photocatalytic activity improvement.     

Room temperature Cl(2) sensing using thick nanoporous films of Sb-doped SnO(2)

Thick film resistive Cl(2) sensors were fabricated using SnO(2) doped with Sb. The nanocrystalline powders of Sb-doped SnO(2) synthesized by a sol-gel method were compressed into an 800?μm thick pellet. The fabricated sensors were tested against gases like Cl(2), Br(2), HCl, NO, NO(2), CHCl(3), NH(3) and H(2). The highest response to Cl(2) was achieved in 0.1% Sb doping where an exposure to 3?ppm of Cl(2) gas led to a 500-fold increase in device resistance. The high sensitivity to Cl(2) is accompanied by minor interference due to other gases at room temperature. It was found that the SnO(2) doped with 0.1% Sb exhibited high response, selectivity (>100 in comparison to the gases described above) and short response time (～60?s) to Cl(2) at 3?ppm level at room temperature.     

A study on major inorganic ion composition of atmospheric aerosols at Tirupati

Atmospheric aerosol samples were collected from an urbanized area (Tirupati, South India) during the period April to September 2001 and were analyzed for major inorganic ions-F, Cl, NO(3,) SO(4), Na, K, Mg, Ca and NH(4) by employing the ion chromatograph. The average mass of the aerosol was found to be 55.64 microgram(-3) with a total water-soluble load (total anion+total cation) of 5.74 microgram(-3). Seasonal distribution of the aerosol mass and temporal variations of the ion concentrations present a clear trend of lowering atmospheric levels during the rainy season due to washout effect. Composition of the aerosols showed higher concentration of SO(4) followed by NO(3) and NH(4) and found to be influenced by local terrestrial sources. The presence of SO(4) and NO(3) may be due to re-suspension of soil particles (formation by heterogeneous oxidation). Ca, Mg and Cl are mainly soil derived ones. The presence of NH(4) may be attributed to the reaction of NH(3) vapors with acidic gases such as H(2)SO(4), HNO(3) and HCl or ammonia vapor may react or condense on an acidic particle surface of anthropogenic origin. Equivalent ratios of NH(4)/(NO(3)+SO(4)) varied between 0.62 and 0.74. It shows the aerosol to be slightly acidic due to the neutralization of basicity by SO(2) and NO(x).     

Ti-Zr-V-O复合催化材料的制备及其选择性催化还原NO

采用溶胶凝胶法制备了Ti-Zr-V-O一体化脱硝复合催化材料,研究了锆掺杂对钛钒复合催化材料脱硝活性的影响,采用X 射线衍射（XRD）、扫描电镜（SEM）、能谱分析（EDS）、傅里叶红外光谱（FT-IR）及N₂物理吸附（BET法）等测试手段,分别考察了锆掺杂对钛钒复合氧化物晶型、结晶形貌、组成、官能团结构及比表面积的影响. 实验结果表明,锆掺杂可以稳定锐钛矿晶型,细化晶粒、抑制晶体生长,改变催化剂的结晶形貌,增强固体酸性,从而优化Ti-Zr-V-O复合催化剂的催化性能. 在Ti-Zr-V-O/ATS 陶瓷颗粒整装催化剂存在下,以NH₃为还原剂进行NO的选择性催化还原脱除,锆掺杂明显拓宽了催化活性温度窗口,往高温区偏移100℃;反应温度为300℃时,NO转化率提高了17.3%.     

Landfill leachate treatment with a novel process: anaerobic ammonium oxidation (Anammox) combined with soil infiltration system

A novel combined process was proposed to treat municipal landfill leachate with high concentrations of ammonium and organics. This process consisted of a partial nitritation reactor (PNR), an anaerobic ammonium oxidation (Anammox) reactor (AR) and two underground soil infiltration systems (USIS-1 and USIS-2). Based on the optimum operating conditions obtained from batch tests of individual unit, the combined process was continuously operated on a bench scale for 166 days. Partial nitritation was performed in a fixed bio-film reactor (PNR, working volume=12 L). Ammonium nitrogen-loading rate (Nv) and DO were combined to monitor partial nitritation, and at T=30+/-1 degrees C, Nv=0.27-1.2 kg/(m3.d), DO=0.8-2.3 mg/L, the ratios of nitrite nitrogen (NO2--N) to ammonium nitrogen (NH4+-N) were successfully kept close to 1.0-1.3 in the effluent. Nitrate nitrogen (NO3--N) less than 43 mg/L was observed. The effluent of PNR was ideally suited as influent of AR. Sixty-nine percent CODcr from the raw leachate was degraded in the PNR. Anammox was carried out in a fixed bio-film reactor (AR, working volume=36 L). At T=30+/-1 degrees C, Nv=0.06-0.11 kg/(m3.d), about 60% NH4+-N and 64% NO2--N in the influent of AR were simultaneously removed. Inhibition of high-strength NO2--N (up to 1011 mg/L) should be responsible for the low removal rate of nitrogen. About 35% aquatic humic substance (AHS) was degraded in the AR. With the same working volume (200 L), USIS-1 and USIS-2 were alternately performed to treat the effluent from AR at one cycle of about 30 days. At hydraulic loading rate (HLR)=0.02-0.04 m3/m3.d, pollutant loading rates (PLR)=NH4+-N相似文献   

Experimental determination of equilibrium constant for the complexing reaction of nitric oxide with hexamminecobalt(II) in aqueous solution

Ammonia solution can be used to scrub NO from the flue gases by adding soluble cobalt(II) salts into the aqueous ammonia solutions. The hexamminecobalt(II), Co(NH3)6(2+), formed by ammonia binding with Co2+ is the active constituent of eliminating NO from the flue gas streams. The hexamminecobalt(II) can combine with NO to form a complex. For the development of this process, the data of the equilibrium constants for the coordination between NO and Co(NH3)6(2+)over a range of temperature is very important. Therefore, a series of experiments were performed in a bubble column to investigate the chemical equilibrium. The equilibrium constant was determined in the temperature range of 30.0-80.0 degrees C under atmospheric pressure at pH 9.14. All experimental data fit the following equation well: [formula: see text] where the enthalpy and entropy are DeltaH degrees = - (44.559 +/- 2.329)kJ mol(-1) and DeltaS degrees = - (109.50 +/- 7.126) J K(-1)mol(-1), respectively.     

原位诱导结晶低温制备α-Al2O3纳米粉体

为了研究在较低的温度下制备α-Al2O3纳米粉体工艺路线,以Al(NO3)3.9H2O和NH3.H2O溶液为原料,经改进的沉淀反应和原位诱导结晶,制备了分散性能良好的α-Al2O3纳米粉体.用XRD、TEM等技术研究了产物的物相、组成和形貌.结果表明,改进的沉淀反应和原位诱导结晶相结合,可有效的降低煅烧温度.在900℃煅烧2 h,即可得到尺寸分布均匀,结晶性好,分散性能良好的α-Al2O3纳米粉体.NH4NO3的存在对于α相变具有明显的促进作用.