外源NO对Cu胁迫下番茄幼苗L-精氨酸代谢的影响

一氧化氮(nitric oxide,NO)作为生物活性分子,广泛参与各种生物和非生物胁迫。采用营养液培养,研究Cu胁迫下番茄体内L-精氨酸、NO、多胺代谢对外源NO的响应机制,以期为铜污染区域蔬菜种植提供科学依据和技术支持。结果表明,Cu胁迫下添加外源SNP(硝普钠,外源NO供体)能够调节番茄根系和叶片中精氨酸脱羧酶(Arginine Decarboxylase,ADC)、鸟氨酸脱羧酶(Ornithine Decarboxylase,ODC)及一氧化氮合酶(Nitric Oxide Synthase,NOS)活性。根系中,外源SNP能够上调NOS活性,L-精氨酸代谢向着NO合成方向进行;叶片中,外源SNP能够同时上调ADC、ODC、NOS活性,PA、NO的合成同时进行;此外,Cu胁迫下添加外源SNP能够增加根系和叶片L-精氨酸含量,而作为PA、NO的合成前体,精氨酸含量升高无疑会间接促进PA、NO的合成,从而提高番茄对Cu胁迫的抵抗能力。     

活性炭纤维负载氧化镧催化净化NO的实验研究

以ACF作为载体制备了负载不同质量分数La₂O₃的负载型催化剂,研究了它们催化净化NO的活性和活性的稳定性,同时对比研究了ACF、HNO₃/ACF净化NO的能力.正交实验结果表明,实验中最佳的氧气体积分数为5%,最佳空速为5 000 m³·(m³·h)^-1;催化实验结果表明,ACF的低温活性很差,HNO₃/ACF净化NO的低温活性很好,但是其活性的稳定性很差;负载了La₂O₃的ACF能大幅提升ACF净化NO的能力,其活性中心为La₂O₃,La₂O₃的最佳负载量为20%,350℃以上时,20% La₂O₃/ACF催化净化NO的效率均在95%以上,在200℃恒温条件下,其催化活性约能持续8h;催化剂的理化特征实验结果表明,ACF、HNO₃/ACF净化NO的机制与负载了La₂O₃的ACF净化NO的机制有着本质的区别.     

EDTA对生物转鼓的NO废气净化效率的影响

生物转鼓过滤器(Rotating Drum Biofilter,RDB)是一种能有效净化氮氧化物废气的新型生物反应器,但在之前的实验发现,由于NO在液相中的低溶解度降低了NO在RDB中的传质效果,从而影响其去除效率。改善气液传质速率是整个反硝化降解NO过程的关键步骤,实验用CuⅡ(EDTA)、ZnⅡ(EDTA)、MgⅡ(EDTA)和FeⅡ(EDTA)等络合剂添加到营养液中,利用NO能与络合剂结合的原理,使得NO能快速溶于液相,从而使NO去除效率由原来平均85%提高到98%。     

Catalytic reduction of nitric oxide with carbon monoxide on copper-cobalt oxides supported on nano-titanium dioxide

A series of copper-cobalt oxides supported on nano-titanium dioxide were prepared for the reduction of nitric oxide with carbon monoxide and characterized using techniques such as XRD, BET and TPR. Catalyst CuCoOx/TiO2 with Cu/Co molar ratio of 1/2, Cu- Co total loading of 30% at the calcination temperature of 350°C formed CuCo2O4 spinel and had the highest activity. NO conversion reached 98.9% at 200°C. Mechanism of the reduction was also investigated, N2O was mainly yielded below 100°C, while N2 was produced instead at higher temperature. O2 was supposed to accelerate the reaction between NOx and CO for its oxidation of NO to give more easily reduced NO2, but the oxidation of CO by O2 to CO2 decreased the speed of the reaction greatly. Either SO2 or H2O had no adverse impact on the activity of NO reduction; however, in the presence of both SO2 and H2O, the catalyst deactivated quickly.     

Characteristics of emissive spectrum and the removal of nitric oxide in N2/O2/NO plasma with argon additive

Although the approach using non-thermal plasma (NTP) for deNOx has been studied for over 15 years, how to achieve higher removal e ciency with lower cost is still a barrier for its industrial application. In order to investigate the impact of the argon additive on electron density, energy and nitric oxide reduction process in plasma, the spectrum of the dielectric barrier discharge at atmospheric pressure in a coaxial reactor was measured using the monochromater with high resolution. The comparative experiments for NO reduction were carried out simultaneously in N2/O2/NO plasma stream with and without argon, respectively. The nitrogen molecular spectrum which is attributed to the energy level transition (C3 u ! B3 g) was compared in the wavelength range 300–480 nm and the electron density and temperature were determined based on the relative intensities and Stark broadening width of spectral lines. The spectrum results indicated that the argon additive could enhance the intensity of emissive spectrum of plasma, thus the electron concentration as well as the energy was increased, and finally prompted the ionization rate to produce active N, O and O3. The results of NO reduction showed that NO conversion e ciency increased in the range of 10%–30% with 5% addition of argon in stream comparing with the condition without argon additive. This study will play a positive role in the industrial application of dielectric barrier discharge deNOx reactor.     

抗坏血酸存在条件下NO2-对玉米植株镉胁迫的缓解作用

植物所吸收的Cd通过与关键的代谢途径、蛋白质的羧基和硫巯基相互作用,或者通过诱导活性氧的迸发而对植物产生毒害作用.大多数植物甚至暴露于低浓度的Cd就会引起明显的中毒症状,因此,揭示缓解Cd胁迫/或提高重金属污染土壤上作物的生产力是一个刻不容缓的问题.植物中的气体多功能信号分子一氧化氮(NO)被证明广泛参与了植物对Cd胁迫的响应和调节,但由于受到成本等因素的限制,其在生产中的应用还不成熟.因此,本文以玉米为实验材料,系统地研究了酸性条件下由抗坏血酸(Vc)和亚硝酸盐(NO-2)反应所产生的NO对植株遭受Cd胁迫的缓解作用.结果表明,10 mmol·L-1的Vc和浓度为0、500、1000、1500、2000、3000、4000、5000μmol·L-1的NaNO2分别进行反应,其缓解Cd胁迫的作用呈先促进后抑制的现象,NaNO2最佳浓度为3000μmol·L-1.与对照相比,适度的Vc+NO-2预处理能够显著增加Cd胁迫下玉米幼苗的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸氧化酶(APX)和谷胱甘肽还原酶(GR)的活性,相应地减少了活性氧过氧化氢(H2O2)和超氧阴离子(O-·2)的积累,降低了膜脂的过氧化伤害.Vc+NO-2还能显著地缓解由Cd造成的叶片黄化现象,维持叶片叶绿素含量的相对稳定;能够在重金属胁迫下增强植物螯合重金属离子的能力,减缓重金属对植株生长发育和生理代谢的影响.由于具有价格低廉且来源方便的特点,Vc+NO-2来源的NO在大田作物抵抗Cd胁迫中具有潜在的应用价值.     

Nitric oxide removal by wastewater bacteria in a biotrickling filter

Nitric oxide(NO) is one of the most important air pollutants in atmosphere mainly emitted from combustion source. A biotrickling filter was designed and operated to remove NO from an air stream using bacteria extracted from the sewage sludge of a municipal sewage treatment plant. To obtain the best operation conditions for the biotrickling filter, orthogonal experiments(L9(34)) were designed. Inlet oxygen concentration was found to be the most significant factor of the biotrickling filter and has a significant negative effect on the system. The optimal conditions of the biotrickling filter occurred at a temperature of 40℃, a pH of 8.0 and a chemical oxygen demand of 165 mg/L in the recycled water with no oxygen in the system. The bacteria sample was detected by DNA sequencing technology and showed 93%–98% similarity to Pseudomonas mendocina. Moreover, a full gene sequencing results indicated the bacterium was a brand new strain and named as P. mendocina DLHK. This strain can transfer nitrate to organic nitrogen. The result suggested the assimilation nitrogen process in this system. Through the isotope experimental analysis, two intermediate products(15NO and 15N2O) were found. The results indicated the denitrification function and capability of the biotrickling filter in removing NO.     

Ceo2/ACFP催化剂低温选择性催化还原NO

采用介质阻挡放电低温氧等离子体技术进行表面改性的活性碳纤维（ACFP）为载体，进行CeO2／ACFP催化剂低温选择性催化还原（SCR）NO的研究。实验结果表明，ACF先经过低温氧等离子体技术进行表面改性后再负载CeO2，能明显提高对NO的去除率。在NO体积分数为1×10^-3、NH3体积分数为2×10^-3、O2体积分数为5％、Ar作为平衡气、反应温度为120—240℃的条件下，较理想的CeO2负载量（质量分数）为9％；在180℃用9％CeO2／ACFP为催化剂时，NO去除率为86．01％。     

烟气脱硝装置臭氧腐蚀性安全评估

根据烟气脱硝装置工艺特点,利用臭氧腐蚀性测试装置,开展了金属材质的腐蚀性研究。通过扫面电镜对不同材质腐蚀前后的表面形貌进行表征,确定了臭氧对不同材质的腐蚀特性,通过理论计算确定了臭氧分解的绝热温升。结合脱硝装置工艺特点对氧气管道流速控制方面进行了分析和总结,根据分析结果给出了建议。     

酸化处理的活性碳纤维负载氧化镧催化还原NO

采用浸渍法制备了负载La2O3的经HNO3活化的活性碳纤维（La2O3／HNO3／ACF）。研究了La2O3／HNO3／ACF对NO的催化活性，研究结果表明：La2O3／HNO3／ACF的低温催化活性远低于La2O3／ACF和HNO3／ACF；随反应温度升高，La2O3／HNO3／ACF对NO的去除率显著提高。La2O3／HNO3／ACF的高温（350℃以上）催化活性很高，优于La2O3／ACF等其他催化剂，且催化活性稳定性很好。La2O3负载量影响La2O3／HNO3／ACF的催化活性，18％La2O3／HNO3／ACF的高温催化活性和活性稳定性最佳，催化活性维持在10h以上。催化剂的扫描电子显微镜和x射线衍射分析结果表明，负载的La2O3多以非晶状态存在于催化剂的表面和内部的孔隙中。