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 62 毫秒
1.
利用聚乙二醇(PEG)改性Bi-PbO2电极电催化氧化茜素绿(AG)模拟染料废水,研究初始质量浓度、电流密度和pH值对降解率的影响.结果表明:高电流密度有利于提高降解率,但可能导致较大的能源浪费;高初始质量浓度有利于提高电流利用率;而pH值不是降解率的主要影响因素.利用红外光谱对AG的氧化过程进行研究,表明AG的氧化主要依靠电解产生的·OH,氧化过程经历了苯环开环、断链,并进一步被氧化为CO2和H2O等小分子化合物.化学动力学研究表明,电催化氧化AG过程符合一级反应动力学规律.  相似文献   

2.
以自制PdOx-RuO2y/Ti电极为阳极,钛板为阴极,研究电催化氧化处理苯胺废水.探讨了电解质浓度、电流密度以及苯胺初始浓度对处理效果的影响.苯胺的降解速率主要取决于电流密度和电解质浓度,随两者的增加均增大;苯胺的初始浓度增大,其降解速率下降,但去除总量随之增加.动力学研究表明,苯胺的电催化氧化过程符合一级反应动力学.采用线性回归方法,确定反应速率常数分别与电流密度的0.712次方、电解质浓度的0.228次方、苯胺初始浓度的-1.147次方成线性关系.  相似文献   

3.
采用复极性三维三相电极反应装置对活性红紫X-2R染料进行了电催化氧化降解试验,分析了外加电压、主电极极间距、电流密度、初始pH值、曝气量等因素对降解效果的影响,确定了最佳工艺条件:外加电压30 V,电流密度28 mA/cm2,主电极极间距5 cm,初始pH值6,曝气量3 L/min,初始质量浓度为400 mg/L的染料废水经50 min电催化氧化后,脱色率与COD的去除率分别达99.1%和93.5%.  相似文献   

4.
采用复极性三维三相电极反应装置对活性红紫X-2R染料进行了电催化氧化降解试验,分析了外加电压、主电极极间距、电流密度、初始pH值、曝气量等因素对降解效果的影响,确定了最佳工艺条件:外加电压30 V,电流密度28 mA/cm2,主电极极间距5 cm,初始pH值6,曝气量3 L/min,初始质量浓度为400 mg/L的染料废水经50 min电催化氧化后,脱色率与COD的去除率分别达99.1%和93.5%.  相似文献   

5.
采用离子膜电解槽电解NaCl溶液,研究制备阳极酸性氧化溶液及其对模拟烟气中NO的脱除效果。分别研究了电流密度、电解时间、Na Cl浓度等因素对阳极酸性氧化溶液理化性能(TOS浓度、pH)的影响。结果表明:随着电流密度、电解时间、NaCl浓度的增加,阳极酸性氧化溶液中TOS浓度近乎呈线性增加。但随着电解时间增加,pH却迅速降低,并趋于稳定(1.5~2)。随着阳极酸性氧化溶液中TOS浓度的增加,NO脱除率明显提高;当TOS浓度为700 mg·L~(-1)时,NO脱除率达到50.4%。随着阳极氧化溶液初始pH的降低,NO脱除率明显增加,当pH为6时,NO脱除率为38%。  相似文献   

6.
用电化学方式持续向TiO2/UV光催化体系中供给H2O2,以促进有机污染物的光催化降解.以碱性品红为模型有机污染物,研究了其在电化学生成H2O2-TiO2/UV体系中的降解,研究结果表明:碱性条件下碱性品红降解最快,酸性其次,中性最慢;在5.0~10.0 mA.cm-2的范围内,碱性品红降解率随电流密度的增大而明显升高,而当电流密度进一步增大时碱性品红的降解率并没有明显的增强;溶液中PO43-、SO42-对碱性品红的降解有抑制作用,而C l-则会促进碱性品红降解;电化学生成H2O2-TiO2/UV对碱性品红的降解率和COD去除率分别高于单一的电化学生成H2O2氧化、TiO2/UV光催化氧化的降解率和COD去除率之和,这表明电化学生成H2O2、TiO2/UV在对碱性品红的降解和COD去除上存在协同效应;碱性品红的降解及COD去除均符合一级动力学过程,其降解及COD去除的速率常数分别为3.109×10-2m in-1和1.033×10-2m in-1.  相似文献   

7.
为通过电催化氧化体系中的极限电流密度(j_(lim))确定电催化氧化过程的传质/传荷界限,分别采用传统测试方法铁氰化钾-亚铁氰化钾体系和反向推导法,评价了两种方法用于测定电催化体系传质系数(k_m)以确定j_(lim)的适用性。通过对酸性红G和愈创木酚的电催化降解实验对传统测试方法进行了验证,测定了不同本体溶液浓度下同一体系k_m;通过对愈创木酚的电催化氧化降解结果进行反向推导,考察了不同电流密度下同一体系的k_m,分析了传质和传荷两种控制阶段下的电解效果和能耗。实验结果表明:使用传统测试方法测定同一体系k_m,其测定结果受本体溶液浓度影响较大;反向推导法相比传统方法更适于测定电催化体系k_m以确定j_(lim);施加不同电流密度,同一体系k_m差异较大,对应j_(lim)无法定量确定;当传荷控制阶段电流密度为50 A/m~2时电解愈创木酚,5 h内能耗为0.018 kW·h/g,远低于传质控制阶段500 A/m~2时的能耗0.135 kW·h/g,但是电解速率较低,愈创木酚的降解需要更长的电解时间。动态电流调控机制可改善长电解时间和高能耗两大缺陷,为电催化氧化技术的进一步工程应用提供参考。  相似文献   

8.
光催化氧化间接电氧化结合降解碱性品红研究   总被引:1,自引:0,他引:1  
研究用UV/TiO2悬浮液光催化氧化和间接电氧化相结合的方法降解一种模型有机污染物——碱性品红.在TiO2悬浮液中引入间接电氧化技术,在紫外光照的同时,利用电化学反应分别在阴阳极上生成H2O2和HClO.一方面它们可以作为氧化剂直接氧化有机物,另一方面它们可以用做电子受体去提高光催化效率.比较了光电结合催化和单一光催化的降解效果,考察了NaCl浓度、电解电流密度、pH值对光电结合催化降解效果的影响.实验结果表明:光电结合催化比单一光催化降解效果有了明显的提高;NaCl浓度对光电结合催化降解效果没有明显的影响;增加电解电流密度对光电结合催化降解有促进作用;碱性条件下降解效果优于酸、中性条件。  相似文献   

9.
Ti/α-PbO2/β-PbO2电极电催化氧化处理苯酚废水   总被引:1,自引:0,他引:1  
采用电催化氧化法,以自制Ti/α-PbO2/β-PbO2电极为阳极,在室温条件下对苯酚模拟废水进行降解研究,探讨电流密度、电极间距、pH值及苯酚初始质量浓度对苯酚降解效率的影响规律.结果表明,在电流密度为600 A·m-2,电极间距为1.0 cm,pH值为3,苯酚初始质量浓度为100 mg·L-1的条件下,苯酚降解效率达92%以上.紫外光谱等实验结果表明,苯酚在氧化降解过程中会产生苯醌等中间产物,苯酚及其中间产物最终被矿化为CO2和H2O.  相似文献   

10.
超声波降解吲哚废水的实验研究   总被引:8,自引:0,他引:8  
研究了吲哚模拟废水在超声波作用下的降解, 并对超声波与电化学协同作用下吲哚的降解规律进行了初步探讨. 考察了废水初始浓度、pH值、处理时间、超声功率、外加催化剂以及声电协同作用下电流密度等因素对吲哚降解的影响. 结果表明, 超声处理吲哚的降解规律符合一级反应; 处理时间越长, 降解率越大; 吲哚初始浓度较低时, 降解率较大; 随着 pH值的增大, 降解率先增大后减小, 在 pH=8左右降解率最大; 降解率随超声功率的增大而增大, 在120 W时达最大值, 随后降低; 加入1 .5 mmol/L H2O2, 对吲哚的降解有较大的促进作用. 在超声波存在下, 电解电流在1 0~2. 2 A范围内, 降解率随电流先增大后减少, 电流为1. 9 A时, 降解率达最大值; 声电化协同作用能提高吲哚的降解率.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

16.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

17.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-  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