首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 406 毫秒
1.
固定化血红蛋白可以作为氧载体,从海水中提取氧气,为人类在水下提供氧源。以聚乙烯醇为载体材料,固定化血红白、制备氧载体。研究了该氧载体的氧解离性能以及戊二醛和六磷酸肌醇对氧载体氧解离性能的影响。  相似文献   

2.
固定化血红蛋白可以作为氧载体,从海水中提取氧气,为人类在水下活动提供氧源。以聚乙烯醇为载体材料,固定化血红蛋白,制备氧载体。研究了该氧载体的氧解离性能以及戊二醛和六磷酸肌醇对氧载体氧解离性能的影响。血红蛋白的固定量达0.6g/g,氧化法测得氧载体的氧解离率为53.3%。戊二醛后交联提高了氧载体的稳定性。六磷酸肌醇使氧解离率由24.8%提高到60.0%。  相似文献   

3.
钴卟啉可与氧发生迅速、可逆的结合反应,是有效的氧载体,已被用于氧气吸收、光学传感器和氧气选择性分离膜。综述了钴卟啉的立体结构、配住体、环境等对其与氧可逆结合性能的影响,以及钴卟啉在功能材料中的应用。  相似文献   

4.
建立利用气相色谱热导检测器分析气体激光器用氦中氧气、氮气、一氧化碳、二氧化碳及氙气混合气体标准物质的方法。试验比较了不同极性、不同类型的色谱柱,对柱箱温度、载气流量进行了优化,最终确定以HP–PLOT/分子筛色谱柱分离氧气、氮气、一氧化碳、氙气,柱箱温度保持40℃,以HP–PLOT Q柱分离二氧化碳,柱箱温度保持60℃,载气流量均为2 m L/min。在混合气体标准物质量值范围内,该分析方法测定结果的相对标准偏差不大于1%(n=6),对重量法配制得标准气体进行分析比对,测量误差不大于1%。  相似文献   

5.
本文利用介质阻挡放电(DBD)方法, 在室温和常压下将甲烷和氧气的混合气体进行等离子体活化, 通过甲烷和氧等离子体直接气相反应高收率合成H2O2. 该方法能有效克服氢氧直接法合成H2O2受到原料气配比严格限制的缺点.  相似文献   

6.
燃烧热测定是一种重要的量热实验,为提高实验质量,我们作了四点改进。 1.改进弹式量热计的放气阀以及充气和漏气的检查为了使试样能完全燃烧,氧弹必需充入氧气,是否已充入,可通过松开放气阀来检查。如氧气减压阀和氧弹充气阀良好,放气嘴松开时  相似文献   

7.
赵东洋 《化学教育》2009,30(11):70-70
提出了利用还原铁粉作为耗氧剂的实验新方法,既测定了空气中氧气的含量,又探究了铁生锈的条件,具有安全环保、探究性强的特点.  相似文献   

8.
高中化学乙种本上册161页[实验6—6]用Cu(NO_3)_2晶体代替KNO_3,做加热分解实验。人们常常直接用带火星的木条去检验Cu(NO_3)_2分解后所得到的混合气体中的氧气。我们认为这种做法是错误的。 1.从反应的方程式上看 2Cu(NO_3)_2=2CuO+4NO_2↑+O_2↑在反应后的混合气体中,氧气所占的体积比为20%,而在空气中,氧气所占的体积比  相似文献   

9.
钴希夫碱配合物及其分子氧加合物的合成与表征   总被引:5,自引:0,他引:5  
以β-萘酚醛与一系列二胺缩合为配体,合成了钴的配合物。通过测定配合物在各种溶剂中吸收的氧气,得到了配合物与分子氧的摩尔比。并从各种溶剂中分离出了一系列2:1和1:1(Co/O_2)的分子氧加合物。对这些配合物和分子氧加合物进行了元素分析,红外、紫外一可见光谱和磁化率的表征,并研究了性质与结构的关系。  相似文献   

10.
自1938年Tsumaki报道犤1犦氧载体以来,这方面的研究已有很大进展犤2犦,只是理论研究居多。氧载体的氧合常数是氧载体研究中的一个重要参数,它的测定是氧载体研究中的一项重要内容,用pH电位法测定氧载体的氧合常数已有研究报道犤2~4犦,作者在研究中发现,邻苯二胺合钴(o-Phdn-Co)配合物在固相和水溶液中与O2反应时表现出很大差异,其反应产物的组成比分别为液相配合物Co∶O2=2∶1,而固相配合物Co∶O2=1∶2,为究其成因和进行理论探讨,有必要先测定其氧合常数。由于o-Phdn-Co配合物的配位常数也未见文献…  相似文献   

11.
Summary The paper presents a new device modifying normal injection port of a gas chromatograph for eliminating air contamination thus enabling determination of traces of oxygen or nitrogen. Further modification is also proposed which enables the analysis to be carried out with a limited quantity of sample gas. Potential application of this device in the analysis of reactive gases like florine has been indicated.  相似文献   

12.
Chemical looping combustion (CLC) is a promising technology for segregation of carbon dioxide. CLC uses a metal oxide as an oxygen carrier, which transfers oxygen from the air to the fuel avoiding direct contact between them, thus separating the carbon dioxide and nitrogen. Cu-based oxygen carriers are excellent mediums due to high reactivity, environmental friendliness, and favorable thermodynamics. However, there are agglomeration issues due to low melting point of Cu. To solve this issue, a new preparation method as well as a dispersion reagent and a thermal durability-enhanced reagent were applied simultaneously to the oxygen carrier. The carriers were synthesized using both wet and dry impregnation methods. Based on the initial oxygen loading capability tests, the dry impregnation method received additional investigation. The characterizations of the oxygen carriers were evaluated using thermogravimetric analyzer (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), and surface area analyzer. TG results demonstrate that the enhanced dry impregnation was an effective preparation method, where the mass loss of the oxygen carrier was typically 3.4 %, correlating to almost 17 % loaded CuO. XRD results indicate a new phase, CuAl2O4 spinel, formed after the first few redox cycles, which is responsible for promoting the thermal stability of the oxygen carriers. SEM results show that the addition of the dispersants decreased the agglomeration and the enhanced reagent chemicals greatly improved the strength of the carriers. However, the surface area of the oxygen carriers decreased with the addition of the additives. In addition, with the increasing redox cycles, the surface area also decreased while the pore size increased, indicating that small pores were crushed, but the reactivity of the oxygen carriers did not decrease. In conclusion, the oxygen carriers produced in this manner are suitable for multi-cycle tests, and a major hurdle toward reducing greenhouse gases has been achieved.  相似文献   

13.
研究了混合稀土储氢合金中氧和氮的测定方法。针对稀土金属高温易挥发、分解的特点,选择适宜的加热温度,使用镍浴,选择高温座坩埚进行试验:选择出了合适的助熔剂的预处理方法。方法已用于实际样品。对含氧0.43%、含氮0.018%的试样,分析精密度为氧4.3%,氮5.9%,加标回收率氧为93%~104%,氮为92%~110%。  相似文献   

14.
The presence of dissolved oxygen inhibits the anodic dissolution of titanium, predominantly in the active range. The reduction rate of oxygen partially limited by its diffusion is shown to depend on the potential and to be localized on active islets each one of which has its own diffusion layer. A mixed kinetics for this reduction reaction is observed in the active range and a pure diffusional one in the near passivity range. The corrosion morphologies are correlated with the various kinetics and localizations observed for the oxygen reduction.  相似文献   

15.
通过低饱和共沉淀法合成了类水滑石结构的层状氢氧化物(Layered Double Hydroxide,LDH)前驱体,经煅烧获得衍生Cu/Al/Zn、Cu/Al/Ni、Cu/Al/Ni/Zn高分散复合氧载体。采用XRD、XRF、H2-TPR、SEM及BET等分析手段对氧载体的结构及反应性能进行了表征,并通过固定床反应器开展了氧载体与生物质化学链气化实验。结果表明,合成的三种前驱体都具有典型的水滑石特征衍射峰,且层板稳定。Cu/Al/Zn前驱体层间厚度为0.264 2 nm,Ni2+引入后,层间距减小。前驱体煅烧后形成的复合氧载体中元素含量与制备试剂基本一致。氧载体中Zn、Ni元素的引入可提升Cu O的反应活性,降低H2还原的反应温度,Zn元素与Cu具有更好的协同作用。Cu/Al/Ni/Zn氧载体在固定床化学链气化中具有较好的碳转化率和气体产率,其碳转化率为82.03%。反应后氧载体比表面积为5.995 m2/g,具有较好的可再生性与抗烧结性,是生物质化学链气化反应较为理想的氧载体。  相似文献   

16.
铈基复合氧化物中晶格氧用于甲烷部分氧化制合成气   总被引:2,自引:0,他引:2  
采用共沉淀法制备了Ce-M-O氧载体(M=Fe、Mn、Cu),并进行了XRD表征。研究了Ce-M-O中晶格氧部分氧化甲烷制合成气的反应。考察了再生时间、再生温度对氧载体部分氧化甲烷性能的影响。研究结果表明, Ce-Fe-O固溶体中的晶格氧适于部分氧化甲烷制合成气。在新鲜的Ce Fe O氧载体上存在少量的强氧化物种,导致开始阶段大部分甲烷被完全氧化,然后该氧载体能均匀地释放出具有高选择性的体相晶格氧将甲烷氧化为CO和H2。通过对氧载体再生条件的控制,可以有效提高目标产物的选择性,当再生温度为850℃,再生时间为7min时, 获得了最大的CO(96.68%)和H2(97.56%)选择性,同时H2与CO摩尔比达到2.02。在无气相氧存在下,用Ce-Fe-O中晶格氧实现甲烷部分氧化制合成气的方法是可行的。  相似文献   

17.
Kunin LL  Bogdanov AA  Rodionov VI 《Talanta》1987,34(1):153-159
A new method has been devised for determination of oxygen in fusible metals and compounds based on them, viz., by electrochemical extraction of oxygen with the help of a specially designed solid electrolyte cell. The physiocochemical conditions for the method to be used, and the analytical characteristics, are discussed. Results are given for determination of oxygen in a number of high-purity fusible metals. The relative standard deviation is inversely proportional to the mean oxygen concentration in the sample.  相似文献   

18.
Copper-based oxygen carriers have high reactivity and favorable thermodynamic properties in the innovative chemical looping combustion (CLC), which results in the inherent capture of CO2. The major challenge of copper-based oxygen carriers is its low melting point and potential thermal sintering and agglomeration under high-temperature cyclic CLC operations. This study is to verify the beneficial use of a rare earth metal (lanthanum) additive in copper for the enhancements of thermal stability of copper-based oxygen carriers. In both the initial 50-cycle tests using TPR-TPO techniques (temperature-programmed reduction and oxidation, 800 °C) and further extended 840-cycle tests using the micro-reactor system, in over 50 cyclic Redox TPR-TPO tests, the lanthanum-promoted copper-based oxygen carrier showed the substantial resistance to the agglomeration. Thermal analysis studies were also extended into investigations of free oxygen releasing from copper-based oxygen carrier. Characterization of used oxygen carriers revealed the significant interaction between copper and its supporting material, Al2O3. The Al2O3-supported CuO seemed to indicate a slow release of oxygen. The formation of a new crystal phase (CuAl2O4), combining CuO and γ-Al2O3, may be a major reason for the stability of copper-based oxygen carrier and the slow oxygen release under oxygen uncoupling condition. The fresh and used oxygen carriers were further characterized by (1) Brunauer–Emmett–Teller for the pore structure analysis, (2) X-ray diffraction for crystal structure analysis, and (3) scanning electron microscopy for surface analysis.  相似文献   

19.
In order to automate the techniques in microanalysis a new series of analyzers utilizing a vertical processing has been developed. Three automatic microanalyzers, i.e., an oxygen, a carbon-hydrogen, and a nitrogen analyzer, are described. For each of them the same type of vertical reactor is used and therefore this design represents an important standardization of this kind of analyzers.Two possibilities for sample introduction are offered. The so-called “automatic introduction device” allows the automatic introduction of the sample into the analyzer; nevertheless it requires the presence of an operator. A fully automated sample introduction is obtained by using the “automatic sample feeder.” This new device can store up to 50 weighed samples and therefore the analyzer runs continuously. These analyzers can carry out an oxygen determination in 7 minutes, a carbon-hydrogen determination in 11 minutes, and a nitrogen determination in 6 minutes. The analyzers can run several hundred determinations continuously.The results reported show a greater reproducibility than that of the results obtained using the classical analyzers, and at least equal accuracy. In addition, the new analyzers have a larger capability; e.g., the oxygen analyzer can determine the oxygen content in organic compounds containing phosphorus and the carbon-hydrogen analyzer allows the determination of the carbon to hydrogen ratio without weighing.  相似文献   

20.
Ultrasound-assisted method for determination of chemical oxygen demand   总被引:1,自引:0,他引:1  
A method for determination chemical oxygen demand (COD) assisted by use of ultrasound has been successfully evaluated for the first time. The method uses instrumentation simpler and cheaper and, in some instances, safer than that used by previous methods for the same purpose. The new device used for sonication is an all-glass cylindrical sonotrode that can be introduced directly into the reaction mixture. Use of this device enables more efficient interaction between sample and ultrasonic energy. The optimized experimental conditions are high ultrasonic power (55% amplitude, 0.9-second pulses each second), high sulfuric acid concentration (>60%), and a sonication time of 2 min. Under these conditions the method has limitations similar to those of the official COD method with regard to the type of organic compound. It works adequately with easily oxidized organic matter (potassium hydrogen phthalate and dextrose) and other organic compounds difficult to oxidize by conventional methods (e.g. phenol and acetic acid) but the COD values obtained with volatile compounds and difficult organic matter are poor. Chloride is tolerated up to a concentration of 7000 mg L(-1) without any masking agent. Gasification of the sample is recommended to improve results; use of air and argon resulted in no significant differences - bubbling with air during sonication resulted in COD values for certified materials and real wastewater samples statistically identical with the certified COD values and those obtained by the classic (open reflux) method. The use of ultrasound energy for COD determination thus seems to be an interesting and promising alternative to conventional oxidation methods used for the same purpose.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号