长期定位有机物料还田对关中平原夏玉米-冬小麦轮作土壤NO排放的影响

农田土壤是大气光化学活性气体一氧化氮(NO)的主要人为源之一.为定量研究有机物料还田对NO排放的影响,利用静态暗箱法对关中平原26 a长期定位施肥夏玉米-冬小麦轮作农田NO排放通量进行周年(2016年6月至2017年6月)观测.除对照(CK)处理全年不施肥外,田间设3个施肥处理,冬小麦季分别为全化肥(NPK,165 kg·hm~(-2))、化肥加秸秆[NPKS,(165+40)kg·hm~(-2)]和化肥加牛粪[NPKM,(50+115)kg·hm~(-2)];夏玉米季均施等量化肥(188 kg·hm~(-2)).观测期内,CK处理NO排放通量较小[12.2 g·(hm~2·d)~(-1)];各施肥处理均在夏玉米播种、施肥和冬小麦施肥后出现排放峰,其中NPK处理峰值最高[112.0 g·(hm~2·d)~(-1)].各处理NO年排放总量和排放系数分别为0.13~0.57 kg·hm~(-2)和0.04%~0.12%.NPKS和NPKM处理年排放总量较NPK分别减少17.6%和增加68.0%(P0.05).与NPK处理相比,NPKS和NPKM冬小麦季排放总量降低41.1%~60.0%(P0.05);但夏玉米季增加25.2%~292.1%(P0.05).冬小麦季添加有机物料有效降低NO排放,而夏玉米季NO排放增加则与土壤有机质含量有关.     

活性焦脱硫脱硝的机理研究

采用质谱仪在线检测的方法,研究了不同组成的模拟烟气在活性焦上的吸附行为;并应用SEM、FT-IR、XPS、BET等手段表征了活性焦的结构性质。结果表明,活性焦脱硫脱硝性能与活性焦的孔隙结构和表面化学特性密切相关,孔容是决定污染物初期脱除率的主要因素;表面官能团则在污染物的化学吸附上发挥着重要作用,是吸附、催化的活化中心;二氧化硫较一氧化氮优先吸附在活性焦上;烟气中氧气或水蒸汽的单独存在对脱硫脱硝均不会有明显的影响,当烟气中同时存在氧气和水蒸汽时,活性焦的脱硫脱硝效果可明显改善;氨的存在既可将一氧化氮还原为氮气,又能增强活性焦脱除二氧化硫的效果。     

COD/TP比及NO_2~--N/TP对短程反硝化聚磷的影响

污水中COD/TP比和NO2--N/TP比对A/A/OSBR反硝化聚磷工艺运行有重要的影响。实验结果表明:随着COD/TP比值的增加,厌氧释磷增加、厌氧释磷速率提高。但当COD/TP比值为28.5时,过剩的碳源进入缺氧段,反硝化菌利用外碳源消耗,抑制了缺氧吸磷过程;当COD/TP比值为21时,合成的PHB不足,缺氧吸磷效率下降,而且长期在较低COD/TP比条件下运行,激发了聚糖菌与聚磷菌的竞争,聚磷菌处于竞争的劣势,反硝化聚磷能力最终消失;当COD/PO43--P为25时,短程反硝化聚磷效果最佳。NO2--N/TP比与COD/TP的比值相关联,在COD/TP=25的条件下,合适的NO2--N/TP比为3。当NO2--N/PO43--P为5时,SBR上一周期剩余的NO2-会影响厌氧释磷过程。当NO2--N/TP为1.8时,NO2-不足,会使反硝化聚磷过程不完全。     

A comparative investigation of NdSrCu_(1-x) Co_x O_(4-δ) and Sm_(1.8) Ce_(0.2) Cu_(1-x) Co_x O_(4-δ) (x:0–0.4) for NO decomposition

A series of single-phase T-structured NdSrCu 1-x Co x O 4-δ with oxygen vacancies and T -structured Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ (x: 0–0.4) with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-programmed desorption (NO-TPD). The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCu 1-x Co x O 4-δ catalysts were of oxygen vacancies whereas the Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ ones possessed excessive oxygen (i.e., over-stoichiometric oxygen); with a rise in Co doping level, the oxygen vacancy density of NdSrCu 1-x Co x O 4-δ decreased while the over-stoichiometric oxygen amount of Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO 3.702 catalyst showing the best efficiency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr -1 , and 600–900°C, the catalytic activity of NO decomposition followed the order of NdSrCuO 3.702 NdSrCu 0.8 Co 0.2 O 3.736 NdSrCu 0.6 Co 0.4 O 3.789 Sm 1.8 Ce 0.2 Cu 0.6 Co 0.4 O 4.187 Sm 1.8 Ce 0.2 Cu 0.8 Co 0.2 O 4.104 Sm 1.8 Ce 0.2 CuO 4.045 , in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu 3+ /Cu 2+ redox ability of NdSrCu 1-x Co x O 4-δ account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.     

哈尔滨市大气主要污染物浓度变化与城市发展因素影响分析研究

采用Daniel趋势检验法对哈尔滨市近年来SO2、NO2和PM10年均浓度变化趋势分析,并对城市总人口与经济、产业结构、民用汽车保有量和能源状况五个城市发展因素进行数据统计分析,用SPSS探究城市发展过程中影响大气污染的因素及相关性.结果表明:浓度变化趋势是SO2明显上升;NO2缓慢上升;PM10整体明显下降,但在2013年点突增至了0.119 mg/m3.SO2与NO2显著相关,相关系数为0.533.经统计,哈尔滨人口经济发展、产业结构调整较为缓慢,全市民用汽车保有量增加并未对NO2浓度影响显著,能源结构依然以煤为主,虽然能源强度提升,但也存在着煤质、散煤的问题.哈尔滨市各城市发展因素与污染物浓度关联度不显著.     

Numerical evaluation of the effectiveness of NO2 and N2O5 generation during the NO ozonation process

Wet scrubbing combined with ozone oxidation has become a promising technology for simultaneous removal of SO₂ and NO_x in exhaust gas. In this paper, a new 20-species, 76-step detailed kinetic mechanism was proposed between O₃ and NO_x. The concentration of N₂O₅ was measured using an in-situ IR spectrometer. The numerical evaluation results kept good pace with both the public experiment results and our experiment results. Key reaction parameters for the generation of NO₂ and N₂O₅ during the NO ozonation process were investigated by a numerical simulation method. The effect of temperature on producing NO₂ was found to be negligible. To produce NO₂, the optimal residence time was 1.25 sec and the molar ratio of O₃/NO about 1. For the generation of N₂O₅, the residence time should be about 8 sec while the temperature of the exhaust gas should be strictly controlled and the molar ratio of O₃/NO about 1.75. This study provided detailed investigations on the reaction parameters of ozonation of NO_x by a numerical simulation method, and the results obtained should be helpful for the design and optimization of ozone oxidation combined with the wet flue gas desulfurization methods (WFGD) method for the removal of NO_x.     

中国东北区域本底大气中酸性气体的研究

龙凤山是我国区域本底站之一,NO_X和SO₂浓度远低于我国空气质量Ⅰ级标准。从1994年8月15日到1995年7月31日首次在龙凤山（127°36′E,44°44′N,330.5m）测得空气中NO_X和SO₂。观测到很强的季节变化,其夏季值最低,冬季值最高。NO_S和SO₂浓度和气象要素密切相关,例如风速、温度和相对湿度。基于排放源以及风频的不均一,不同扇区来的空气质量能有很大变化。在SSE－SW扇区出现高浓度SO₂、较高浓度NO_X和高〔SO₂〕/〔NO_X〕,表明该扇区有城市污染物的输送。SW－NNE扇区有高NO_X、低SO₂及低的〔SO₂/〔NO_X〕,表明该方向城市烟羽难以直接影响测点,在这个扇区高NOX来源于当地农民做饭、取暖时秸杆焚烧。低NO_X、SO₂观测在NNE－SSE扇区,这意味着这是最清洁扇区。     

农田NO排放的自动观测

详细介绍农田ＮＯ排放自动观测的方法原理,系统整体构造及电路和气路配置,并讨论了观测结果的可靠性。同地,还就已取得的一些初步研究结果进行了分析,对华东秋,冬季麦田的ＮＯ排放进行自动连续观测的结果表明,秋季麦田的ＮＯ排放具有与温度几乎完全同步的日变化规律。     

农田NO排放的时间变异性

在采用基于箱法的自动观测技术对苏州地区一个完整的科小麦生育期的麦田的ＮＯ排放进行全天候连续观测的基础上,讨论了ＮＯ排放的季节变化和日变化特征及其温度和植物生长的影响,观测实验发现,苏州地区上麦田的ＮＯ排放具有极其显著的季节变化规律怀,冬季以前２的小麦苗期物返青至淹水种稻之前的春季,ＮＯ排放量分别为０．１５６－０．７５８ｍｇ·ｍ＾－２·ｈ＾－１和１．２２９－１０．８０２·ｍ＾－２·ｈ＾－１,前者是全     

ZrO2负载过渡金属氧化物催化剂对CO＋NO（O2）反应的影响

本文运用固定床微反技术考察了Ｃｕ,Ｆｅ,Ｍｎ,Ｃｒ,Ｃｏ和Ｎｉ负载（ＺｒＯ２载体）氧化物对ＣＯ＋ＮＯ（Ｏ２）反应的催化活性。研究了ＮＯ和ＣＯ在不同比例时,催化剂对Ｎ２Ｏ和Ｎ２生成的影响。结果表明,在ＮＯ＋ＣＯ反应中,ＮＯ和ＣＯ的比例对催化剂活性和Ｎ２Ｏ,Ｎ２生成均有明显的影响,ＣｕＯｘ／ＺｒＯ２催化剂的活性最高;Ｎ２Ｏ是ＮＯ＋ＣＯ反应的中间产物,低温或ＮＯ过量时有利于生成Ｎ２Ｏ,高温或ＮＯ不足时有