施用量及降雨量对碳酸氢铵化肥在砂壤土中垂向迁移转化的影响

土壤氮素是制约作物产量和品质的主要环境因素之一,施用氮肥对农业生产的发展起着重要的作用,研究碳酸氢铵的迁移转化规律对于现代农业发展具有重要意义。通过室内土柱试验对不同碳酸氢铵化肥施用量和不同降雨量进行模拟,在充分供水条件下,抽取土柱不同高度处不同时间的水样,通过测量氨氮、硝态氮和总氮的浓度,分析无机氮垂向迁移转化的规律。结果表明,浅层土中氨氮浓度急剧降低,深层土中氨氮浓度先增加后降低;化肥施用量越多,氨氮浓度变化趋势越平缓;降雨量越大,氨氮损失量越高;硝态氮浓度先增加后降低;化肥施用量越高,硝态氮浓度变化趋势越剧烈;降雨量的变化对硝态氮浓度影响不大;总氮浓度变化趋势与氨氮保持一致。     

水解酸化-SBR工艺处理调味品废水的研究

通过考察水解酸化-SBR工艺对调味品废水处理效果,同时对处理后的调味品废水进行脱色处理。实验结果表明:进水COD为580 mg/L左右,反应时间为3 h,出水COD低于100 mg/L。出水氨氮、亚硝酸盐和硝酸盐均低于10 mg/L,出水的磷酸盐低于1 mg/L。SBR出水采投加用聚合氯化铝20 mg/L,粉末活性炭投加2 g进行脱色处理,色度的去除效果最好。     

有机固体废弃物堆肥过程中PAO及PNO的研究

研究了污水处理厂滤泥与甘蔗叶混合堆肥的过程及氮素转化规律。主要考察堆肥温度、pH、氨氮与亚硝酸盐氮的含量及氨氧化率(PAO)和亚硝酸盐氧化率(PNO)的转化规律。结果表明,堆肥温度在第4天达到最大值55.3℃;堆肥pH在第6天达到最大值7.89;氨氮和亚硝酸盐氮的含量随时间发生变化,高温阶段氨氮含量维持在较高水平,亚硝酸盐氮却在较低水平范围内波动。研究了PAO与PNO的变化趋势,二者与作用微生物的活性和所需反应底物的含量相关。     

人类活动对丰水季节浅水湖泊磷素赋存特征的影响

以实测数据为依据,对受到不同方式人类活动影响下的丰水期九龙口、大纵湖、蜈蚣湖和得胜湖4个浅水湖泊进行研究,解析畜禽养殖、航运、围网养殖及原始湖荡湿地等不同类型的浅水湖泊在丰水季节沉积物—水界面中上覆水、间隙水和沉积物中磷素的赋存形态,并探究不同形态磷素的垂向分布规律。结果表明,丰水季节湖泊中各形态磷素在上覆水、间隙水和沉积物三者之间存在较大的浓度梯度,表现为沉积物间隙水上覆水;四个湖泊上覆水中总磷(TP)浓度介于0.12~0.21mg/L之间,PO_4~(3-)浓度为0.05~0.18mg/L,已达富营养化标准;各形态磷素分布受人类活动影响明显,有污水输入的得胜湖和围网养殖严重的湖泊TP含量较高,而刚经过疏浚的九龙口TP、PO_4~(3-)平均浓度最低;总体上各形态磷素在垂向分布上多表现为锯齿状波动,分布差别较大,间隙水中碱性磷酸酶(APA)表层4cm以上呈锯齿状变化,4cm以下多呈锯齿状降低或平缓降低;沉积物中PO_4~(3-)随深度的增加呈现锯齿状变化;沉积物中有机磷的矿化作用明显,草型湖泊各形态磷相对低于其他湖泊,APA明显高于其他湖泊。     

黄壁庄水库水质评价及氮污染成因分析

根据2006~2016年黄壁庄水库水质监测数据,选取溶解氧、总氮、总磷等8项指标为评价因子,基于模糊数学综合评价法对水库水质进行评价,确定水库主要污染因子,并对主要污染因子成因进行分析。结果表明,黄壁庄水库水质综合评价为地表水Ⅴ类水质,主要受总氮指标影响,其他评价指标基本符合地表水Ⅱ类水质。过高的总氮浓度主要源于较高的硝酸盐氮,来水硝酸盐氮含量高,且库内反硝化作用受抑制,是导致水库硝酸盐氮含量高的主要原因,同时季节变化对库区硝酸盐氮含量也有一定影响。该研究对保护水源地水质,保障黄壁庄水库安全供水具有重要意义。     

DO对倒置A2/O-MBR组合工艺处理低C/N废水效果的影响研究

通过采用倒置A_2/O-MBR组合工艺探究溶解氧对于低C/N废水效果的影响研究。实验结果表明,DO为2 mg/L时处理效果最好,COD、NH_4~+-N、TN、以及TP的平均出水质量浓度和平均去除率分别为:13.16、1.59、20.76、1.16和91.62%、96.02%、48.11%、71.36%。溶解氧(DO)、氨氮(NH_4~+-N)、总氮(TN)、以及总磷(TP)的影响效果较为明显。     

基于GMS的江南某地区浅层地下水溶质迁移规律分析

为研究江南某地区浅层点源污染对地下水水质影响,对观测数据进行校准和验证,基于GMS构建研究区概念模型及数学模型,分析有无外源污染入渗时地下水中常规污染指标CODMn的周期性迁移趋势。结果显示,生活污水点源入渗对地下水水质影响较大,模拟周期为18个月、15年,45年时,CODMn污染晕浓度分别为0.007~0.137、0.008~0.155、0.009~0.157mg/L,最大迁移距离分别为125、256、368m,核心区和外圈区域等值线浓度分别为0.104~0.137、0.118~0.155、0.118~0.156mg/L及0.024~0.039、0.027~0.045、0.028~0.045mg/L;相对无外源污染汇入时CODMn污染晕浓度最大升高了3倍、最大迁移距离最远延伸了98.9%、扩散范围最多增大了2.2倍,其中点污染源入渗处CODMn浓度变化波动较大,不稳定性较高。据此建议加强地表水与地下水污染同步管理,同时应用GMS模拟分析海绵城市规划与建设过程中各类低影响开发(LID)措施削减污染物的效果与长期迁移趋势,并计算具体量化指标,避免各类LID措施削减地表污染的同时,却造成地下水污染。     

MBR工艺在生活污水处理中同步脱氮除磷效果

采用一体化MBR工艺技术处理厂区生活污水,在溶解氧DO质量浓度为0.1～3.5 mg/L,MLSS为12 650mg/L的条件下,该工艺对COD、NH4-N和TP的平均去除率分别为88.9%、94.6%和61.60%。检测结果表明:MBR具有良好的降解COD和同步脱氮除磷的效果,这对于污水处理厂的脱氮除磷改造具有重大意义。     

绍兴某污水厂工业污水深度脱氮小试试验研究

绍兴某工业园区污水处理厂进水以印染污水为主,经二级生化处理后,其出水总氮(TN)远高于12mg/L的排放标准,必须进行深度脱氮处理才能达标排放。本试验采用反硝化滤池对二级出水进行了深度脱氮小试研究,进水TN在36.8~55.3mg/L之间变化,平均值为44.2mg/L,反硝化滤池运行参数为停留时间60min,外加碳源采用无水乙酸钠(98%)、投加量为200mg/L,最终滤池出水TN在9.1~12.6mg/L之间变化,平均值为10.6mg/L,达到排放标准。     

短程硝化污泥工业化培养方法探究

该文研究了短程硝化污泥工业化培养富集方法。实验采用工业级生物反应器,通过24 h的游离氨抑制启动和定性运行筛选,进行培养。研究结果表明：产出污泥的亚硝酸盐氮积累率维持在89%,比氨氧化速率为20.30 mg/(g·h),最佳培养启动浓度为3 000 mg/L～3 500 mg/L,反应器稳定产泥量为0.18 kg/(m³·d);污泥生物群落变化表明较短时间可实现目标菌的筛选。证明了该工业化培养新方法的可行性。     

The individual role of pyrrolic,pyridinic and graphitic nitrogen in the growth kinetics of Pd NPs on N-rGO followed by a comprehensive study on ORR

In order to develop and replace the expensive PtC catalyst from the fuel cells, we have attempted to synthesize an efficient catalyst for oxygen reduction reaction (ORR) in an alkaline media. The materials were initially fabricated as follows; (a) synthesizing a nitrogen doped (para-xylylenediamine, nitrogen precursor) graphene oxide (N-rGO); (b) synthesizing palladium nanoparticles on graphene oxide surface (rGO-Pd). The electrochemical analysis showed that the ORR path on the N-rGO catalyst is observed to follow 2-electron mechanism. Conversely, the onset potential, current density and surface area of the rGO-Pd doesn't match with the commercially available PtC catalyst. To overcome these flaws, we have combined the individual effects of each component and fabricated N-rGO-Pd nanocomposite. The covalent interaction between nitrogen part of para-xylylenediamine with oxygenated functionalities of GO, followed by a strong π–π stacking interaction between the aromatic ring of para-xylylenediamine and GO altered the electronic distribution of the carbon support, induced more defects, influenced the size and averted the self agglomeration of the Pd NPs which lead to the astonishing catalytic activity of N-rGO-Pd catalyst. Furthermore, various spectroscopic techniques revealed the individual influence of pyrrolic, pyridinic and graphitic–N on the synthesis, size and extraordinary distribution of Pd NPs.     

火焰中形成的二氧化氮和氧化亚氮

本文研究了燃烧各种燃烧的炉膛内二氧化氮（＊ＮＯ２）和氧化亚氮（Ｎ２Ｏ）的形成过程及其放水平,讨论了氧化氮（ＮＯＸ）各组成部分之间的相互转变规律及影响ＮＯ２和Ｎ２Ｏ形成与排放的主要因素。     

氧对宜宾煤中燃料氮迁移特性的影响

利用X射线光电子能谱，研究了宜宾煤与煤焦中氮的形态，探讨了氧对煤中燃料氮迁移规律的影响．制焦气氛为高纯氩气中的惰性热解和氧／氩混合气氛．制焦温度为700℃和900℃．结果表明，煤焦中氮官能团的存在形式受温度控制，与气氛无关，但是温度和氧量对各官能团量的变化都有影响．氧的参与造成热解时燃料氮迁移规律的改变，这种改变随温度的升高愈加明显．有氧存在时，焦中氮的总含量随温度的升高迅速减少．实验结果分析说明，煤焦N-X中氧的来源是煤本身结合的燃料氧，而热解气氛中氧的参与不会造成N-6和N-Q转变为吡啶酮和N-X．各种氮官能团形式随温度的升高都有不同程度的减少，惰性热解条件下的各官能团相互转化现象在有氧存在时不明显．     

煤粉锅炉低负荷工况下的低氮燃烧试验与应用

在锅炉低负荷情况下通过试验方法确定有效降低锅炉NOx的排放浓度的运行调整方式，达到降低NOx排放的目的。     

GCr15钢LF增氮因素分析及措施

分析了GCr15轴承钢“LD→ LF→ VD→ CC”生产工艺中的氮含量情况及LF精炼过程中钢水增氮的原因.结果表明,LF精炼阶段的“原材料”和“钢液裸露”是造成钢液增氮的最主要原因.提出了GCr 15轴承钢LF精炼过程控氮措施,通过工业试验,降低了精炼过程氮的增加,使成品氮含量得到有效控制.     

氮基气氛热处理的氮气源

介绍了氮气在热处理气氛中的作用，评述了不同的供氮方式和制氮方法，讨论了ＰＳＡ制氮装置的稳定性，提出了ＰＳＡ制氮目前乃是我国氮基气氛热处理氮气源的适宜方案。     

炼油加热炉烟气的污染及其防治

炼油加热炉通过烟气排放的主要污染物是氮氧化物(NOx)和硫氧化物(SOx)。介绍了氮氧化物和硫氧化物对环境的危害和国内主要限制排放标准。分析了氮氧化物和硫氧化物的生成原理,提出了氮氧化物和硫氧化物排放量、排放速率以及排放高度的测算方法。减少氮氧化物和硫氧化物排放的主要途径为:燃烧前对燃料进行预处理、燃烧过程中减少污染物的生成、燃烧后对烟气进行后处理。介绍了燃料预处理阶段的胺法脱硫技术,燃烧阶段的以烟气内回流低NOx燃烧器为代表的低NOx燃烧技术,以及烟气处理阶段的选择性非催化还原脱氮技术(SNCR)、选择性催化还原脱氮技术(SCR)和脱硫、脱氮、除尘三位一体化技术。此外,本文还强调炼油加热炉大型化后不仅要重视氮氧化物和硫氧化物排放的浓度,更要重视氮氧化物和硫氧化物的排放速率。     

Some aspects of the formation of nitric oxide during the combustion of biomass fuels in a laboratory furnace

The influence of bed-region stoichiometric ratio and fuel nitrogen content on the formation of gaseous species formed during grate combustion of biomass fuels is reported based on gas measurements made within the fuel bed. Three fuels were studied: two mixtures of pelletized bark and wood chips and one of pelletized straw. Experiments were performed in a vertical, cylindrical, laboratory-scale grate-furnace with 0.245 m i.d. and 1.8 m height. Primary air was supplied through a grate consisting of a steel plate with 340 holes of 3.7 mm diameter. Secondary air was supplied 0.66 m above the grate. Gas analysis was performed for O₂, CO₂, CO, H₂ and NO. Results were compared with values calculated using a computer program for thermochemical equilibrium conditions. The measured contents of O₂, CO₂, CO and H₂ show good agreement with calculated equilibrium conditions at all bed region stoichiometries. A higher formation of NO was found for the straw fuel (0.58% fuel nitrogen) than for the bark/wood chip fuels (≈0.25% fuel nitrogen). This is not in accordance with the thermochemical equilibrium calculations indicating that the formation of nitric oxide does not attain thermochemical equilibrium and that the nitrogen content of the fuel has an influence on the amount of NO that is formed. The fuel nitrogen conversion to NO ranged from 3 to 20% at reducing conditions and from 20 to 40% at bed region stoichiometries between 1.00 and 1.25.     

Incorporation of pyridinic and graphitic N to Ni@CNTs: As a competent electrocatalyst for hydrogen evolution reaction

Cheap production of hydrogen (H₂) from eco-friendly routes is preeminent for solving future energy challenges. This study explores the hydrogen evolution reaction (HER) activity of nickel (Ni) nanoparticles and nitrogen doped carbon nanotubes (NiNCNTs), which are fabricated by a cheap and one-step pyrolysis method. The most active catalyst synthesized at 800°C exhibits an overpotential of 0.244 V to reach a current density of 10 mA cm⁻², Tafel slope of 93.3 mV dec⁻¹ and a satisfactory 10 hours stability. Low resistance and large ECSA value of the sample also favor the competent response for HER in alkaline media. The robust HER activity of the catalyst is as a result of the nickel nanoparticles which are the active spots of reaction; while the presence of well-developed nitrogen containing carbon nanotubes with large content of pyridinic and graphitic nitrogen may provide high-electron density and feasible routes for its transportation to deliver an outstanding HER performance.     

Influence of temperature and steam on the products from the flash pyrolysis of Jordan oil shale

Oil shale samples from the Sultani deposit in the south of Jordan, were pyrolysed in a semi‐continuous fluidized bed reactor under nitrogen and nitrogen/steam atmosphere. The pyrolysis temperature between 400 and 650°C were investigated. Increasing the pyrolysis temperature from 400 to 520°C caused a large increase in the oil yield. Further increase of the pyrolysis temperature resulted in a decrease in oil yield and a large increase in the evolved gases. This increase in the hydrocarbon gas yield was attributed to oil thermal cracking reactions. The evolved gases were composed of H₂, CO, CO₂, and hydrocarbons from C₁ to C₄. The presence of steam improved the oil yield which may be a result of reducing the degree of decomposition. The derived oils were fractionated into chemical classes using mini‐column liquid chromatography. Copyright © 2002 John Wiley & Sons, Ltd.