Corrosion of carbon steel,zinc and copper by air pollution in Chongqing

This paper presents the research on the atmospheric corrosion rates of carbon steel, zinc and copper in Chongqing, which was a corrosion subprogram of an international project, Regional Air Pollution in Developing Countries. We performed field exposure tests of carbon steel, zinc and copper at an urban site Guanyinqiao and a rural site Tieshanping inChongqing, then used grey relational analysis, based on the database of the whole corrosion project, to determine the order of the effect of environmental factors on corrosion rates of tested metals, and established dose-response functions for these three metals. The results showed that the two crucial agents of acidic environment, SO2 and H+, were common factors that contributed most to the corrosion of the tested metals. The established dose-response functions for outdoor carbon steel and zinc are proved applicable to use in Chongqing, but the function for copper needs further modifying. We employed these dose- response functions and general environmental data to elaborate the maps of corrosion rate respectively of carbon steel and zinc by geological information system (GIS) technique which help to identify areas of high corrosion damage risk. An acceptable annual average SO2 level of 21 μg/m3 for carbon steel and that of 61 μg/m3 for zinc are also put forward to control the air pollution impact on atmospheric corrosion in Chongqing urban areas.

EFFECT OF CHLORIDE ON THE ATMOSPHERIC CORROSION OF SIMULATED ARTIFACT IRON IN NO_3^- BEARING POLLUTANT ENVIRONMENT

The effect of chloride in nitrogen-bearing pollutant on the atmospheric corrosion of cast iron was investigated by using periodic wet-dry test, electrochemical experiment and surface tension test. Scanning electron microscopy （SEM） with energy disperse atomic X-ray （EDAX） was used to identify the corrosion processes and products. The results of the weight loss measurement showed that the whale corrosion kinetics can be approximately described by： AW=At^8. With the addition of NaCI, B increases. The result presented that CI^- accelerated the corrosion rate obviously during the whale corrosion process. The initial corrosion process was investigated from the viewpoint of surface tension. At the initial corrosion period, the corrosion rate was proportion to the adsorption of anions contained the solutions. And as corrosion went on, the penetration effect of anions and different characteristics of the corrosion products began to dominant the corrosion process, which led to the accelerated effect.

Effect of Chloride on the Atmospheric Corrosion of Cast Iron in Sulphur or Nitrogen-Bearing Pollutant Environment

The effect of chloride on the atmospheric corrosion of cast iron in sulphur or nitrogen-bearing pollutant was investigated by using periodic wet-dry test, electrochemical experiment and surface tension test. Scanning electron microscopy coupled with energy dispersive atomic （EDAX） and stereoscopic microscopy was used to identify the corrosion processes and products. Cl^- and NO3^- were shown accelerating effects during the whole corrosion process but depression effects were observed in Cl^- and HSO3^- bearing pollutant at the initial corrosion stage. However, with the corrosion going on, the depression effects was less obviously and the initial corrosion process was investigated from the viewpoint of surface activity. At the initial corrosion stage, the corrosion rate was proportional to the adsorptivity of anions, but as corrosion went on, the penetration effect of anions and different characteristics of the corrosion products began to dominate the corrosion process, which led to changes on the corrosion rate.

Sulfate-Reducing Bacteria Impact on Copper Corrosion Behavior in Natural Seawater Environment

In this study, the electrochemical corrosion behavior of copper was investigated in seawater collected from four different marine zones of Agadir coastal. These zones are different by the degree of pollution in order to study the effect of this pollution on the copper corrosion, especially the microbial pollution by sulfate reducing-bacteria (SRB). So, to prove this relationship, the microbiological analyses researching the SRB are realized. In parallel, the electrochemical impedance measurement and atomic absorption analysis are established to compare the microbiological evolution cycles with the electrochemical behavior of copper during the immersion period. In the results, we found a good correlation between the growth cycle of marine sulfate-reducing bacteria and the copper corrosion rate by the sulfur and extracellular polymeric substances (EPS) produced as bacteria metabolites. Additionally, this corrosion rate depends on the immersed time: it is maximal after the first or second month depending on the marine zone.

Mechanistic modeling of copper corrosions in data center environments

Air-side economizers are increasingly used to take advantage of“free-cooling”in data centers with the intent of reducing the carbon footprint of buildings.However,they can introduce outdoor pollutants to indoor environment of data centers and cause corrosion damage to the information technology equipment.To evaluate the reliability of information technology equipment under various thermal and air-pollution conditions,a mechanistic model based on multi-ion transport and chemical reactions was developed.The model was used to predict Cu corrosion caused by Cl_(2)-containing pollutant mixtures.It also accounted for the effects of temperature(25℃and 28℃),relative humidity(50%,75%,and 95%),and synergism.It also identified higher air temperature as a corrosion barrier and higher relative humidity as a corrosion accelerator,which agreed well with the experimental results.The average root mean square error of the prediction was 13.7Å.The model can be used to evaluate the thermal guideline for data centers design and operation when Cl_(2)is present based on pre-established acceptable risk of corrosion in data centers’environment.

碳钢在达州典型大气环境下的腐蚀行为研究

通过1年期现场暴露试验、腐蚀速率分析、锈层形貌观察、锈层组成分析及电化学测试等试验方法,研究了Q235碳钢在达州典型大气环境下的腐蚀行为。结果表明,位于工业大气环境的达州市通川区,Q235碳钢的腐蚀速率为23.78μm/a,而位于乡村大气环境的达州市万源市,Q235碳钢的腐蚀速率仅为10.33μm/a。Q235碳钢表面腐蚀产物主要组成为γ-FeOOH、α-FeOOH和Fe 3 O 4。电化学结果表明,在达州重工业环境下的碳钢腐蚀较为严重,腐蚀产物层电阻和电荷转移电阻均高于达州乡村环境,说明其表面锈层能有效保护基体,减缓基体的进一步腐蚀。

污泥热干化的研究进展

首先阐述了在热干化过程中污泥的理化性质变化,污泥中大分子有机物分解为小分子有机物,酸溶态、可氧化态、可还原态等重金属形态转变为稳定的残渣态,降低了污泥处置的环境风险。随后,分析了污泥热干化过程出现的问题及其成因,针对污泥黏滞问题,总结了干污泥返混、添加降黏性物质及改造干化设备等方法;针对污染气体问题,综述了加入添加剂和降低温度抑制污染气体的释放,采用吸收法、吸附法和生物法处理产生的污染气体;针对设备腐蚀问题,归纳了采用防腐管材、防腐涂层、投加缓蚀剂和降低污泥含砂量的主要措施。最后对污泥热干化技术的研究趋势和发展提出了建议。

A1060纯Al在模拟污染海洋大气环境中的腐蚀行为及机理

通过周期浸润加速腐蚀试验和电化学测试,采用3.5%(质量分数)NaCl和3.5%NaCl+0.02 mol/L NaHSO_(3)溶液分别模拟海洋大气环境和污染海洋大气环境,研究了A1060纯Al在这两种环境中的腐蚀行为。结果表明:A1060纯Al在污染海洋大气环境中表现出更大的腐蚀电流密度和更低的自腐蚀电位,分别为1.01μA/cm^(2)和-911 mV;经720 h周期浸润腐蚀试验后,其在模拟污染海洋大气环境中的质量损失量和腐蚀速率分别为9.7 g/m^(2)和0.04μm/a,其腐蚀速率是在模拟海洋大气环境中的4倍,且其在污染海洋大气环境中还面临着更早和更加严重的点蚀情况;污染海洋大气中的HSO_(3)^(-)诱导A1060纯Al表面保护性氧化膜转变成疏松的Al_(2)(SO_(4))_(3),导致薄液膜的酸性和导电性均增加,从而促进腐蚀反应的发生。

火电厂烟塔合一技术应用现状与现存问题分析

【目的】烟塔合一技术是火电厂提高能效的重要改造手段,但是实际运行对现有系统造成的不利影响也不容忽视。为此,对烟塔合一技术应用现状及其在运行中存在的问题进行分析,并提出处理对策。【方法】通过综合分析现有研究,探讨了烟塔合一技术改造后造成环境影响、冷却塔塔体腐蚀以及循环冷却水水质恶化的成因和形成机理。【结果】根据计算流体动力学(computational fluid dynamics,CFD)对烟气排放轨迹以及污染物落地浓度的模拟结果,可合理设置防护距离,并通过塔顶加装挡板预防极端天气下的烟气下洗现象;针对不同部位,可采用不同防腐涂料对冷却塔进行防腐改造,以延长其使用寿命;为控制和优化循环水质,需采用深度水处理方法优化药剂投加,并适当控制循环水排污量与补水量,以维持其运行可持续性。【结论】通过采取适当的应对措施,可以有效缓解烟塔合一技术改造所带来的负面影响,提高火电厂环境效益和经济效益。

高湿区域输电线路金具锈蚀多因素影响分析模型

对地区污染总体情况以及输电线路金具腐蚀的诱因进行了分析,提出了分析方法以及防护措施。结果表明:四川区域酸性湿沉降主要分布在川南和川西区域,分布在夏秋季节;高硫污染高酸型湿沉降环境,是金具腐蚀速率加快的环境外因;由此建立了输电线路金具锈蚀多因素模型,获取金具区域腐蚀分布图;还提出金具材料防腐、线路图像识别以及输电线路维护等多种防护措施。相关结果为高湿区域输电线路金具锈蚀防护提供了参考。

E2.8国四发动机后处理系统SCR混合器腐蚀问题分析

发动机的后处理系统是车辆的重要零部件之一。通过分析轻卡车辆后处理选择性催化还原(SCR)混合器腐蚀问题的实际案例,结合E2.8国四发动机后处理系统的工作原理、结构特点及设计要求等方面,排查出后处理SCR混合器腐蚀的根本原因,并依此合理制定措施并进行改进优化,从根本上解决了腐蚀导致的漏气和排放污染的问题。

尿素水解器泄漏导致汽水系统污染事故分析

某热电机组启动过程中发生尿素水解器加热盘管泄漏,主要原因是尿素质量不合格,尿素水解液中存在氯化钠腐蚀水解器加热盘管并导致断裂,尿素溶液通过疏水回收进入机组汽水系统,致使汽水污染,最终使得炉右前屏过热器泄漏,经调度同意1号机停运消缺。

The Influence of Gaseous Pollutants on Silver Artifacts Tarnishing

The present work investigated the effect of the common gaseous pollutants on silver artifacts corrosion. The study will be carried out on manufactured coupons of silver alloy (91 silver, 9 copper) which have chemical composition similar to ancient Egyptian silver artifacts. These coupons will be exposed to gaseous pollutants of each individual gas;such as Sulfur dioxide, Nitrogen dioxide, Carbon dioxide, Hydrogen sulfide and Chlorine. The exposure period will be four weeks in a climate chamber with gas concentration 10 PPM. After the test Examinations by SEM and PM were used to evaluate the effect of each gas and description the morphology of the corrosion layers. The results revealed that all gases reacted with the surface except carbon dioxide. The formed tarnishing layers varied in coverage and density rate. Corrosion products are analyzed by XRD and the results revealed Ag2S, AgCl, Ag2SO4 and Ag2O as corrosion products.

Erratum to the Influence of Gaseous Pollutants on Silver Artifacts Tarnishing, Vol. 6 (2017), 135-148

The original online version of this article Salem, Y. (2017) The Influence of Gaseous Pollutants on Silver Artifacts Tarnishing. Open Journal of Air Pollution, 6, 135-148. doi: 10.4236/ojap.2017.64011 unfortunately contains grammar mistakes. The author wishes to correct the errors. The present work investigated the effect of common gaseous pollutants on silver artifacts. The study was carried out on coupons made of a silver alloy (91 silver and 9% copper) with chemical composition similar to ancient Egyptian silver artifacts. These coupons were exposed to gaseous pollutants such as sulfur dioxide, nitrogen dioxide, carbon dioxide, hydrogen sulfide and chlorine, each gas separately. The exposure period was four weeks inside a climate chamber with 10 PPM concentration of each gas. After each test, examinations by SEM and PM were used to evaluate the effect of each gas and observe the formed tarnish layers. The results revealed that all gases reacted with the surface except carbon dioxide. The formed tarnish layers varied in coverage and density rate, and the heaviest layer was of H2S coupons. The tested coupons were analyzed by XRD and the results revealed Ag2S, AgCl, Ag2SO4, Ag(NO3)3(NO)3, AgO and Ag2O as corrosion products.

工业污染区输电铁塔构件的大气腐蚀与防护

文章针对工业污染区服役20 a的高压输电铁塔构件,开展大气腐蚀与防护状况研究,揭示腐蚀机理。结果表明,工业污染区输电铁塔构件的大气腐蚀是一个电化学腐蚀过程,即使在同一角钢构件上,也存在腐蚀程度不同的区域。严重腐蚀区域镀锌层完全消失,腐蚀层开裂、碎化,失去对钢基体的保护。在污垢层未清除干净的钢构件表面涂覆铝防腐层,形成结瘤区域,雨水携带大气中的粉尘进入铝防腐层与镀锌钢之间的间隙中,加剧镀锌层与钢基体的腐蚀。相比而言,表面平整区域的铝防腐层和镀锌层完好,钢基体无腐蚀。处于工业污染区的输电铁塔构件表面镀锌层的防护有限,在严格遵守科学的操作规范时,表面涂装是十分有效的补充防护措施。

碱性腐蚀对超疏水涂层绝缘强度的影响

为了探究碱性腐蚀对超疏水涂层绝缘强度的影响,本研究制备了具有绝缘性能的超疏水涂层试样,并对其进行人工碱性腐蚀试验。对不同腐蚀程度的超疏水涂层试样的绝缘强度进行测试,并研究了不同温度下染污程度、外加电压幅值和表面污秽润湿程度对其绝缘强度的影响。结果表明:碱性环境会破坏超疏水涂层表面的物质和结构,导致其疏水性和自清洁性能下降,进而导致其绝缘强度下降。在脏污湿润环境下受到碱性腐蚀的超疏水涂层表面染污程度越严重、外加电压越高、表面污秽润湿时间越短,涂层表面的绝缘强度越低。碱性腐蚀超疏水涂层表面染污程度随着润湿时间的增加逐渐下降至稳定值,此时涂层的表面泄漏电流不发生明显变化,且碱性腐蚀环境温度越低,达到上述稳定状态所需的润湿时间越短。

贵阳市阅山湖地下水污染成因分析--以金牛泉为例

阅山湖东南岸金牛泉自2019年4月以来曾发生多次污染事件,通过分析泉域范围内水文地质条件及对潜在污染源的排查,发现万达广场1号、3号排污管网存在污水渗漏现象,为明确金牛泉污染成因及污染物来源,采用高密度电法对万达广场与金牛泉之间碳酸盐岩地层中岩溶发育情况及富水状况进行探测,并采用地下水示踪试验对万达广场排污管网中污水的渗流去向加以验证,最终得知万达广场位于地下水径流带上,其下伏地层溶蚀裂隙、构造裂隙、溶洞等较为发育,为地下水向金牛泉径流提供了有利途径,1号、3号排污管网污水渗漏后,沿着溶蚀裂隙、构造裂隙等向金牛泉方向径流,最终造成了金牛泉地下水污染。

基于材料摩擦的纳米发电机在水体应用领域的研究进展

摩擦纳米发电机(TENG)自从被发明出来之后就得到了很大的发展,利用TENG收集水能受到了许多研究者的关注,同时TENG这种能源摩擦材料在水体上的应用也得到了很大的发展。本文基于TENG在水体方面的应用,从水体金属抗腐蚀、水体传感器、水体污染处理三个应用领域阐述了其发展和研究进展,并总结其发展趋势。

淋溶酸性溶液对SnPb焊料中重金属浸出及电化学特性的影响

为研究重金属元素在土壤中的浸出迁移特性,评价其环境污染风险程度,以电子产品SnPb焊料为对象,研究填埋时不同酸性溶液对焊料重金属元素的腐蚀浸出行为以及腐蚀电化学特性的影响,对淋溶液中重金属浸出速率、表面腐蚀产物及形貌和动电位极化曲线等进行分析。结果表明:SnPb焊料在淋溶H_(2)SO_(4)⁃HNO_(3)溶液中腐蚀电流密度最高,表面腐蚀产物为PbSO_(4),Sn的浸出速率最大,在淋溶HNO3⁃HCl溶液中的腐蚀电流密度较低,Pb的浸出速率最大。因此,SnPb焊料在淋溶H_(2)SO_(4)⁃HNO_(3)溶液条件下,Sn对地下水的污染风险高,Pb对土壤的污染风险高;在淋溶HNO_(3)⁃HCl溶液条件下,Pb对地下水的污染风险很高。

水泥窑协同处置市政干化污泥的工程实践

水泥窑协同处置污泥技术是在生产水泥熟料的过程中同时处置污泥,充分利用烧制熟料的高温烟气进行焚烧污泥,热效率高,尾气处理成本低,既回收了污泥中可再利用的能源,又实现了物资的再利用。在利用水泥窑系统处置市政干化污泥的工程实践中,不仅要重视污泥处置对水泥窑系统热工制度、预热器结皮以及窑筒体腐蚀的影响,还要采取措施保障系统对污染物的达标排放。