自由基对高压电缆中间接头析氢腐蚀过程的影响
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Influence of Radicals on Hydrogen Evolution Corrosion Process of High Voltage Cable Intermediate Joints
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通讯作者: 文柯成,E-mail:15282139842@163.com,研究方向为自由基高级氧化技术
收稿日期: 2025-06-03 修回日期: 2025-07-15
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Corresponding authors: WEN Kecheng, E-mail:15282139842@163.com
Received: 2025-06-03 Revised: 2025-07-15
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作者简介 About authors
刘凡,男,1978年生,博士,教授级高级工程师
针对电缆接头中两种典型的金属/乙烯-醋酸乙烯酯共聚物(EVA)界面,通过阶梯递增电流法-析氢实验系统研究其产氢电流密度阈值、产氢速率和饱和产氢浓度的析氢特性,以及开路电位、电化学阻抗和Tafel曲线等电化学性质,并详细揭示了自由基在加剧金属材料析氢腐蚀中的作用机制。通过自由基淬灭实验和电子顺磁共振测试,确定了在电化学析氢腐蚀过程中主要的自由基为氢自由基(
关键词:
The hydrogen evolution characteristics of two typical metal/ethylene-vinyl acetate copolymer (EVA) interfaces for cable joints were investigated by hydrogen evolution test with stepwise increasing current method, especially in term of the hydrogen production current density threshold, hydrogen production rate, and saturated hydrogen concentration, as well as electrochemical properties such as open-circuit potential, electrochemical impedance, and Tafel curves etc. It also elucidates the mechanism by which radicals exacerbate hydrogen evolution corrosion in metal materials. By using radical quenching agents to inhibit hydrogen evolution and conducting electron paramagnetic resonance detection during the hydrogen evolution process, it is established that the main radicals in the electrochemical hydrogen evolution corrosion process are hydrogen radicals (
Keywords:
本文引用格式
刘凡, 刘凤莲, 范松海, 邵千秋, 周凯, 李泽瑞, 陈熠东, 文柯成, 张静.
LIU Fan, LIU Fenglian, FAN Songhai, SHAO Qianqiu, ZHOU Kai, LI Zerui, CHEN Yidong, WEN Kecheng, ZHANG Jing.
近年高压电缆中间接头事故频发,严重威胁输电系统安全运行[1~3],其根本原因在于接头结构的复杂性:接头内部集成大量的金属组件提供电缆的环流泄放通道和防水保护的作用[4~6]。高压电缆中间接头通常由金属缆芯和连接管、均压套、硅橡胶预制件和Cu壳等部件组成,形成Al、Cu等金属材料与交联聚乙烯、乙烯-醋酸乙烯酯共聚物(EVA)等有机材料的多相界面体系。在长期运行中,3方面因素协同诱发腐蚀析氢风险:其一,泄漏电流波动,工况变化导致界面电势分布动态变化[7];其二,密封失效风险:水分侵入使金属-聚合物界面形成电化学微电池;其三,材料电化学耦合:金属与导电性聚合物(如半导层)在电解液中构成腐蚀电偶。上述过程不仅加速金属阳极溶解,更可能触发析氢反应(HER),致使氢气在密闭腔体内累积,最终引发灾难性故障。
现有研究普遍认为,水分是引发电缆中间接头发生电化学腐蚀的关键因素,可导致接头发生不可逆腐蚀损伤。在中性水溶液环境中,接头金属材料(Al、Cu等)首先发生耗氧腐蚀,金属阳极释放电子成为金属离子或氧化物[15,16],同时溶解氧在阴极发生还原反应。除耗氧腐蚀外,溶液中的阴极还可能会发生H+还原产生H2的析氢反应[7,9,17]。然而,H2的生成并不是的简单化学过程,其反应路径需首先生成氢自由基(
基于此,本研究选取电缆接头中典型的Al/EVA和Cu/EVA界面为代表,考察两种组合的析氢腐蚀特性,并系统探讨分析了电缆接头中金属结构腐蚀产氢过程中自由基的作用及具体机制。
1 实验方法
本研究采用如图1a所示的定制产氢测试平台。该平台将氢气传感器固定于电解池顶盖下侧5 cm处,实时监测氢气浓度变化;电解池外部缝隙均匀涂覆硅脂以确保气密性,并配备输出电压范围为0~330 V的交流电源。实验采用阶梯递增电流法研究金属/EVA复合结构的产氢电流密度阈值:初始施加恒定小电流密度,若5 min内未检测到H2信号,则逐步提升电流密度值并重复监测,直至5 min内获得稳定H2信号,此时电流密度值即为阈值。确定阈值后,通过调节电源设定不同电流密度值开展产氢实验。
图1
图1
金属析氢实验平台和电化学实验平台
Fig.1
Metal hydrogen evolution experiment platform (a) and electrochemical experiment platform (b)
电化学测试平台如图1b所示,由CHI660E型电化学工作站及三电极系统构成,待测金属片作为工作电极,铂片为辅助电极,饱和甘汞电极(SCE)为参比电极。测试流程严格遵循无损优先原则,向电解池注入超纯水后,先测定开路电位(OCP)、电化学阻抗谱(EIS),再测定Tafel曲线,并对Tafel曲线进行拟合,获取腐蚀电位(Ecorr)以及腐蚀电流密度(Icorr)值。OCP测试时间为100 s,EIS测试频率上下限为105~10-1 Hz,Tafel曲线电压测试范围为-1.0~1.0 V。测试后清洁金属片并进行析氢实验,析氢结束后重复上述电化学测试流程,以获取腐蚀后数据。为进一步解析析氢腐蚀过程中自由基的种类,进行了电子顺磁共振(EPR)测试。
使用Helios G4 UC型的双束超高分辨场发射扫描电镜(SEM)并配备能量色散X射线光谱仪(EDS)观察Fe-C材料的尺寸大小和形状,并对表面元素进行分析。用Rigaku Ultimate IV型X射线衍射仪(XRD)分析腐蚀产物的物相组成,靶材为Co靶,扫描速率为4 (°)/min,扫描范围为20°~110°。
2 结果与讨论
2.1 金属/EVA结构的析氢腐蚀特性
为探究电缆接头中典型的金属/EVA结构的析氢特性,模拟了Al/EVA界面和Cu/EVA界面进行产氢电流密度阈值测试。如图2a所示,在所设置条件下,实验测得Al/EVA界面阈值(54 A/m2)显著低于Cu/EVA界面(200 A/m2)。析氢实验前金属材料的OCP测试结果(图2b)显示:Al和Cu的稳定OCP分别为-0.961和-0.264 V。根据电化学理论[28,29],OCP负移意味着材料费米能级升高,表明其表面电子偶空穴转移的能力增强,氧化倾向显著增大。Al的OCP较Cu负移0.697 V,证实其更易作为阳极发生氧化反应并发生析氢过程,这一特性使得Al/EVA界面在较低电流密度下即会发生腐蚀并析氢。
图2
图2
Al/EVA和Cu/EVA的析氢电流阈值及Al和Cu析氢前的OCP曲线
Fig.2
Hydrogen evolution current thresholds for Al/EVA and Cu/EVA (a) and OCP of Al and Cu prior to hydrogen evolution (b)
对Al/EVA与Cu/EVA界面分别施加1倍和3倍阈值电流密度的恒流极化。利用Origin软件对取样点数据进行拟合,得到析氢拟合曲线。测试结果(图3)显示,两种组合的析氢速率均随反应时间递增而逐渐降低,最终达到饱和状态,原因在于随着反应推进,金属表面腐蚀产物不断累积覆盖反应位点,进而使反应速率减缓直至停止。当电流密度提高时,两种组合在相同时间点的析氢速率显著提升,且饱和析氢浓度亦大幅增加。这一现象归因于电流密度增大加剧了金属片的电化学腐蚀程度,从而提高了析氢效率。相较于Cu/EVA组合,Al/EVA组合的析氢速率和饱和析氢浓度均显著更高,这可能源于Al的OCP显著低于Cu,在电化学腐蚀过程中更易发生电子转移,进而导致更高的析氢活性。
图3
图3
不同电流密度下Al/EVA和Cu/EVA的析氢曲线
Fig.3
Hydrogen evolution curves for two interfaces at different current densities
图4
图4
加入自由基淬灭剂前后Al/EVA和Cu/EVA的析氢曲线
Fig.4
Hydrogen evolution curves for Al/EVA and Cu/EVA interfaces before and after adding radical quencher
2.2 自由基在金属腐蚀过程中的作用
2.2.1 电化学测试
为深入探究自由基在金属/EVA界面析氢腐蚀过程中的作用机制,考察了添加淬灭剂前后两种金属试样的OCP、EIS以及Tafel曲线。OCP的测试结果如图5所示,4种测试条件下的OCP均随测试时间延长呈现轻微正向偏移并最终趋于稳定。与析氢前的OCP值(图2b)相比,Al的OCP由析氢前的-0.961 V显著正移至-0.049 V,Cu的OCP由-0.261 V正移至0.031 V。OCP的正向偏移现象可归因于材料表面腐蚀产物的累积对阳极反应的抑制作用,表明Al/EVA和Cu/EVA界面中的金属材料在析氢过程中均受到了严重的腐蚀损伤。值得注意的是,在析氢前添加自由基淬灭剂后,析氢后Al的OCP值由-0.049 V显著负移至-0.447 V,Cu的OCP值由0.031 V负移至-0.049 V。OCP的负向偏移现象表明,自由基淬灭剂的引入有效降低了材料表面的腐蚀程度,证实了自由基在金属析氢腐蚀过程中的促进作用。
图5
图5
加入自由基淬灭剂前后Al/EVA和Cu/EVA析氢后的OCP曲线
Fig.5
OCP for two interfaces after hydrogen evolution with and without radical quencher addition: (a) Al/EVA, (b) Cu/EVA
图6
图6
加入自由基淬灭剂前后Al/EVA和Cu/EVA产氢后的EIS谱
Fig.6
EIS for two interfaces after hydrogen evolution with and without radical quencher addition
表1 加入自由基淬灭剂前后Al/EVA和Cu/EVA产氢后的拟合阻抗值
Table 1
| Experimental group | Rct / Ω·cm2 | Rtotal / Ω·cm2 |
|---|---|---|
| Al/EVA | 22517 | 45192 |
| Al/EVA, radical quencher | 19184 | 37753 |
| Cu/EVA | 12506 | 33733 |
| Cu/EVA, radical quencher | 11521 | 29427 |
图7
图7
加入自由基淬灭剂前后Al/EVA和Cu/EVA产氢后的Tafel曲线
Fig.7
Tafel curves for two interfaces after hydrogen evolution with and without radical quencher addition: (a) Al/EVA, (b) Cu/EVA
表2 加入自由基淬灭剂前后Al/EVA和Cu/EVA产氢后的Tafel曲线拟合值
Table 2
| Experimental Group | Ecorr / V | Icorr / A·cm-2 |
|---|---|---|
| Al/EVA | -0.444 | 5.924 × 10-7 |
| Al/EVA, radical quencher | -0.486 | 3.363 × 10-6 |
| Cu/EVA | -0.146 | 1.220 × 10-7 |
| Cu/EVA, radical quencher | -0.489 | 3.211 × 10-6 |
2.2.2 金属试样的腐蚀形貌
析氢反应后的Al和Cu试样的表面光学显微形貌(图8)显示,析氢腐蚀前,金属表面呈现典型金属光泽,未见明显腐蚀产物。未添加自由基淬灭剂时,析氢反应后金属表面金属光泽基本消失,覆盖有大量致密、无金属光泽的腐蚀产物层。相比之下,添加淬灭剂后,析氢反应后金属表面腐蚀产物显著减少,部分区域仍可见未受腐蚀的原始金属表面形貌。
图8
图8
析氢腐蚀前后金属Al和Cu试样的光学显微镜形貌
Fig.8
Optical micrographs of metallic specimens: (a) as-prepared Al, (b) post-hydrogen evolution Al, (c) Al after hydrogen evolution with radical quencher addition, (d) as-prepared Cu, (e) post-hydrogen evolution Cu, (f) Cu after hydrogen evolution with and without radical quencher addition
图9为析氢实验后Al和Cu试样的微观SEM形貌和对应的EDS分析结果。相较于添加自由基淬灭剂组,未添加淬灭剂的Al和Cu试样表面腐蚀更为显著,表面粗糙度增大,均匀分布有大量腐蚀产物颗粒,表明试样整体遭受了相对均匀的腐蚀。添加自由基淬灭剂后,Al和Cu试样表面更为平整,附着腐蚀产物颗粒数量显著减少。EDS分析结果进一步支持了上述形貌观察:添加淬灭剂试样表面的氧含量显著降低,基体金属元素(Al或Cu)含量则相对升高,证实了自由基淬灭剂对金属氧化腐蚀过程具有显著的抑制作用。
图9
图9
析氢腐蚀前后金属Al和Cu试样的SEM图及EDS谱图
Fig.9
SEM micrographs and EDS spectra of metallic specimens after hydrogen evolution corrosion: (a) Al without radical quencher, (b) Al with radical quencher, (c) Cu without radical quencher, (d) Cu with radical quencher
析氢实验后Al和Cu试样的XRD谱如图10所示。分析表明,图10a中的衍射峰分别归属于Al (标准PDF#04-7887)和羟基氧化铝(AlOOH,标准PDF#48-0890)。根据溶解再沉积理论[31],Al在腐蚀过程中溶解形成Al3+,随后Al3+在溶液环境中与阴离子结合形成AlOOH。值得注意的是,添加淬灭剂后,Al的特征峰强度增强,而AlOOH特征峰强度减弱,表明淬灭剂的加入有效抑制了Al的腐蚀过程。图10b中的Cu试样的衍射峰则归属于金属Cu (标准PDF#85-1326)和Cu2O(标准PDF#77-0199),Cu2O生成源于Cu在水溶液环境中不完全氧化。与Al试样规律一致,添加自由基淬灭剂后,Cu试样中氧化产物特征峰强度减弱,证实了淬灭剂对Cu腐蚀同样具有抑制作用。综合XRD与前述EDS分析结果,二者协同证实了自由基的产生显著加剧了Al和Cu的腐蚀进程。
图10
图10
析氢腐蚀后金属Al和Cu试样的XRD图谱
Fig.10
XRD patterns of Al (a) and Cu (b) sheet samples after hydrogen evolution corrosion
以
综上可知,在金属析氢腐蚀过程中,自由基不仅显著提升了材料的析氢速率及饱和析氢量,同时亦强烈加剧了材料的腐蚀程度。
2.3 自由基的鉴定及贡献评价
鉴于自由基显著促进金属材料的析氢腐蚀,其在电缆接头腐蚀机制中的作用不容忽视。为深入探究金属/EVA组合在析氢腐蚀过程中自由基的生成行为,本研究选取亚甲基蓝(Methylene blue, MB)作为自由基捕获剂[35,36]。在析氢实验前,向电解液中加入0.22 μmol/L的MB,实验过程中,利用分光光度法实时监测MB浓度变化。定义C0为MB的初始浓度(t = 0 min时),Ct为t时刻的MB浓度,以Ct/C0反映MB的去除率,Ct/C0的降低直接反映了体系中所产生的氧化性自由基作用大小。MB去除率曲线如图11所示。Al/EVA与Cu/EVA体系中的MB去除率分别达到14.01%和12.30%,证实了两种金属/EVA组合在析氢腐蚀过程中均伴随有氧化性自由基持续生成。Al/EVA体系中MB的去除速率高于Cu/EVA,原因在于Al与EVA间更快的电子转移速率,从而促进了氧化性自由基的生成动力学。
图11
图11
Al/EVA和Cu/EVA体系下MB的去除率曲线
Fig.11
Removal efficiency curves of MB for Al/EVA and Cu/EVA interfaces
常见的氧化性自由基如
图12
图12
Al/EVA和Cu/EVA体系加入自由基淬灭剂后MB的去除率曲线和降解动力学拟合曲线
Fig.12
MB removal efficiency curves for Al/EVA system (a) and Cu/EVA system (b), and degradation kinetics fitting curves for Al/EVA system (c) and Cu/EVA system (d)
为进一步解析析氢腐蚀过程中自由基的种类,进行了电子顺磁共振(EPR)测试,结果示于图13。实验采用5,5-二甲基-1-吡咯啉-N-氧化物(DMPO)作为自由基捕获剂。DMPO与
图13
图13
DMPO-OH及DMPO-H标准EPR图谱及Al/EVA和Cu/EVA体系的EPR图谱
Fig.13
EPR spectra of DMPO-OH and DMPO-H standards and test results for Al/EVA and Cu/EVA systems
综上,在电缆中间接头的金属/EVA结构析氢腐蚀过程中会产生还原性自由基
2.4 析氢腐蚀过程中自由基的生成及可能的作用机制
前述证实,电缆中间接头的金属/EVA结构在析氢腐蚀过程中产生了
氧化性自由基
综上所述,电缆接头中金属/EVA结构电化学腐蚀析氢过程中自由基的可能产生途径和作用机制如图14所示。
图14
图14
金属/EVA结构中自由基生成及作用机制图
Fig.14
Possible mechanism of radical generation and action in metals/EVA structures
3 结论
(1) 电缆接头处金属材料Al与Cu在模拟地下水环境中的OCP值分别为-0.961和-0.264 V,相较于Cu/EVA,Al/EVA界面仅需更小的电流密度即会诱发析氢腐蚀。
(2) 自由基加速金属材料的析氢腐蚀过程,提高H2生成速率。向金属/EVA结构引入自由基淬灭剂,材料的产氢速率和饱和产氢浓度得到显著抑制,同时有效阻滞金属材料的电化学腐蚀。
(3) 电缆接头处金属/EVA结构电化学腐蚀过程中产生多种自由基,还原性自由基为
参考文献
Statistical analysis on failures of 110 kV and above power cable system
[J].With the maturity of power cable technology and updating of new technology of cable accessories, the failure characteristics of high voltage cable systems and fault causes have changed significantly. In this paper, detailed statistics are carried out for the characteristics and fault cause proportions of 132 failures for 110 kV and above power cable in China Southern Power Grid(CSG)during 2006 and 2016, and 99 failures in the literatures, and the fault characteristics and main reasons of the high voltage cable system in recent years are analyzed. The statistical results show that the present operation reliability of high-voltage cable system in CSG has been improved significantly, while the failure rate has decreased by an order of magnitude compared to 2001. Cable accessories have now already become the weakest part of high-voltage cable systems, the failures of which account for as high as 85.5% without taking external damage into account. For cable, more than 70% of the cable failures are due to external damage, while more than 84% cable accessories failures are due to product quality and improper installation. The statistical result of power cable system can provide a basis for the development of differentiated operation and maintenance strategy.
110 kV及以上电力电缆系统故障统计分析
[J].随着电力电缆技术的不断成熟以及电缆附件新技术的不断更新,高压电缆线路的故障特点及各故障原因占比已发生了较大变化。本文通过对南方电网在2006—2016年间发生的132起110 kV及以上电缆系统故障及文献查阅的99起故障案例进行详细统计,全面分析了近年来高压电缆系统的故障特征及其主要原因。统计结果表明:相比2001年,目前南方电网高压电缆线路运行可靠性明显提高,故障率下降了约一个数量级;电缆附件已成为目前高压电缆线路的最大薄弱环节,在不计及外力破坏时,电缆附件故障占比高达85.5%;对于电缆本体,70%以上的故障是由于外力破坏造成,而对于电缆附件故障,84%以上是由于产品质量和施工安装不当引起。该统计分析结果可为制订电力电缆系统差异化运维策略提供依据。
Research on ultrasonic testing of internal defects in silicone rubber materials for cable joints
[J].
电缆接头硅橡胶材料内部缺陷的超声检测研究
[J].
Simulation study on effect of defects on temperature distribution of cable intermediate joint
[J].
缺陷对电缆中间接头温度分布影响的仿真研究
[J].
On detection of crack defects in lead seal of high voltage cable
[J].
高压电缆铅封裂纹缺陷检测方法研究
[J].
High temperature insulation materials for DC cable insulation-Part III: Degradation and surface breakdown
[J].
Temperature dependent electrical properties of thermoplastic polypropylene nanocomposites for HVDC cable insulation
[J].
Electrochemical corrosion and water inflow defect diagnosis of lead sealing section of intermediate joint for high voltage cable
[J].
高压电缆中间接头铅封段电化学腐蚀及进水缺陷诊断
[J].
Corrosion factors and mechanisms of buffer layer and aluminum sheath inside high-voltage cable
[J].
Hydrogen evolution and electromigration in the corrosion of aluminium metal sheath inside high‐voltage cables
[J].
Evaluation technology of water-blocking buffer layer of high voltage cable based on stages classification of gases evolution
[J].
基于分阶段产气的高压电缆阻水缓冲层状态评估
[J].
Analysis on degradation of high-voltage power cable joints
[J].
高压电力电缆接头劣化分析
[J].
The partial discharge evolution characteristics of 10 kV XLPE cable joint
[J].
Influence of morphological variations on the AC breakdown of XLPE insulation in submarine cable factory joints
[J].
The corrosion analysis and prevention of secondary cable joints used in outdoor terminal boxes of substation in humid environment
[J].
Corrosion and wear corrosion behavior of FH40 marine steel in simulated polar seawater environment
[J].
FH40船用钢在模拟极地海水环境中的腐蚀与磨蚀行为
[J].为了研究船用钢在极地海冰水-微生物-低温复杂环境中的服役行为,利用模拟海水和含嗜冷杆菌的2216E液体培养基按比例混合以模拟极地海水溶液,通过浸泡实验和电化学测试评估F级船用钢的低温腐蚀行为,并模拟测试其耐极地冰水磨蚀性能。结果表明:FH40钢微观结构主要由铁素体和少量珠光体组成,存在少量含Al、Ti、Si的常见夹杂物。钢材在模拟极地海水中的腐蚀速率为(0.238 ± 0.005) mm/a,腐蚀产物由γ-FeOOH、α-FeOOH、Fe<sub>2</sub>O<sub>3</sub>/Fe<sub>3</sub>O<sub>4</sub>和嗜冷杆菌微生物被膜组成,疏松多孔的腐蚀产物膜和极地微生物的局部覆盖协同诱导点蚀的形成。钢材在模拟极地海水环境中的摩擦系数为0.41,单位历程磨损失重率为4.1 × 10<sup>-5</sup> g/(N·m·s),磨损体积为0.019 mm<sup>3</sup>,电化学腐蚀磨损机理为机械去除和腐蚀去除混合模型。另外,摩擦将加剧船用钢的局部腐蚀并降低锈层的腐蚀保护性,而磨损试样继续腐蚀则能缓解磨痕区域的点蚀现象并降低磨痕宽度。
Effect of cyclic strengthening on corrosion behavior of 7075 Al-alloy
[J].
循环强化对7075铝合金腐蚀行为的影响
[J].7075航空铝合金在沿海地区服役环境下,因海水飞溅或大气盐雾腐蚀而经常出现腐蚀损伤。因此,针对7075铝合金强度高但耐蚀性差这一问题,采用室温循环强化(Cyclic strengthening,CS)工艺以提高其强度及耐蚀性。与传统峰时效T6相比,7075铝合金经循环强化后表现出更好的耐蚀性,在电化学测试中具有更高的自腐蚀电位和更高的阻抗值。在NaCl溶液中,T6试样的晶间腐蚀深度为58 μm,而CS试样的腐蚀深度仅为15 μm;在盐雾腐蚀中,CS试样形成的腐蚀坑和腐蚀微裂纹比T6试样更小。T6和CS试样的腐蚀产物中均含有Zn(OH)<sub>2</sub>和ZnCl<sub>2</sub>,其形成过程分别为T6试样晶界处的η′(MgZn<sub>2</sub>)相、CS试样中的原子团簇与铝基体之间电化学反应。经过CS工艺处理后,7075铝合金晶体内部产生大量位错与原子团簇,这阻碍位错运动并提高自腐蚀电位,进而提高材料的强度及耐蚀性。
Phenomena of white spots on the buffer layer and mechanisms of hydrogen evolution corrosion inside high-voltage cables
[J].
高压电缆阻水缓冲层的白斑现象及析氢腐蚀机理
[J].
Amorphous metallic ultrathin nanostructures: A latent ultra-high-density atomic-level catalyst for electrochemical energy conversion
[J].
Amorphizing noble metal chalcogenide catalysts at the single-layer limit towards hydrogen production
[J].
Electron spin resonance evidence for electro-generated hydroxyl radicals
[J].
Enhancement of Fe-C micro-electrolysis in water by magnetic field: Mechanism, influential factors and application effectiveness
[J].
Effect of temperature on electric‐thermal properties of semi‐conductive shielding layer and insulation layer for high‐voltage cable
[J].
Effect of low-density polyethylene on properties of ethylene-vinyl based semi-conductive shielding materials
[J].
Ion concentrations and their spatial variability in underground water and surface water in typical terrestrial ecosystems in China
[J].The water chemistry data monitored during 2010-2015 by 33 terrestrial ecological stations from the Chinese Ecosystem Research Network (CERN) and the National Ecosystem Research Network of China (CNERN) were used to characterize ion concentrations and their spatial variability in underground water, still surface water, and flowing surface water from typical terrestrial ecosystems. The results showed the presence of mass-based concentrations of major anions, including HCO> SO> Cl> CO. Among them, HCO and SO were dominant, and their sums accounted for 71.7%, 75.3%, and 74.9% of the total anions in underground water, still surface water, and flowing surface water, respectively. Cations were mainly Ca and Na, and their sums accounted for 69.7%, 64.8%, and 68.9% of the total cations in underground water, still surface water, and flowing surface water, respectively. The ion concentration and ion ratio in the underground water, still surface water, and flowing surface water differed largely among the studied regions. The hydrochemical type varied regionally, e.g., Na-Mg-SO-Cl type, usually with high content of salinity, was found in the underground water of ecological systems in the Northwest arid and semiarid areas and in the East Huanghuaihai Plain; Ca-SO-HCO type in underground water and Ca-HCO-SO type in surface water were found in hilly areas with subtropical red soil; Na-Ca-HCO-Cl type was present in underground water of south hilly areas with subtropical latosolic red soil; and Ca-HCO and Ca-Mg-HCO types were found in other ecological systems. Hydrochemical types had low inter-annual variation for both underground water and surface water.
我国典型陆地生态系统水化学离子特征及空间分布
[J].
Hydrochemical characteristics and genesis analysis of shallow groundwater in Tiantai Basin
[J].Taking the Tiantai Basin as the research area,shallow groundwater and surface water samples were collected and their chemical compositions were detected.The hydrochemical characteristics and genesis of shallow groundwater were discussed by means of hydrochemical statistical analysis and ion ratio.The results showed that the hydrochemical types in the study area are mainly HCO<sub>3</sub>-Ca type and HCO<sub>3</sub>-Ca·Na type.The concentration of HCO<sup>-</sup><sub>3</sub>,Ca<sup>2+</sup>,Na<sup>+</sup>,Cl<sup>-</sup> was lower in the surrounding area and higher in the middle area,and the concentration of NO<sup>-</sup><sub>3</sub> and SO<sup>2-</sup><sub>4</sub> was higher in the northwest area.The chemical composition of shallow groundwater was affected by rock weathering and human activities.The main ions were mainly derived from the dissolution of silicate minerals,and were affected by agricultural activities and domestic sewage discharge.The comprehensive study on the hydrochemical characteristics and genesis of groundwater in Tiantai Basin can provide basic data support for the protection and utilization of water resources.
天台盆地浅层地下水水化学特征及成因分析
[J].以天台盆地为研究区,采集浅层地下水和地表水样品并检测其化学成分,通过水化学统计分析、离子比值等方法,重点探讨浅层地下水的水化学特征及成因。结果表明,研究区水化学类型以HCO<sub>3</sub>-Ca型、HCO<sub>3</sub>-Ca·Na型为主;离子成分具空间分异性,呈现HCO<sup>-</sup><sub>3</sub>、Ca<sup>2+</sup>、Na<sup>+</sup>、Cl<sup>-</sup>浓度周围低中间高,NO<sup>-</sup><sub>3</sub>和SO<sup>2-</sup><sub>4</sub>浓度西北部较高特征;浅层地下水化学成分受岩石风化及人类活动影响,主要离子主要来源于硅酸盐矿物溶解作用,并受农业活动和生活污水排放影响。开展天台盆地地下水水化学特征及成因的综合研究可以为水资源的保护及利用提供基础数据支撑。
Hydrochemical characteristics and control factors of shallow groundwater in Anqing section of the Yangtze River Basin
[J].
长江流域安庆段浅层地下水水化学特征及控制因素
[J].
Analysis on hydrochemical characteristics and origin of the main ions of shallow groundwater in redbed of Suining Area, central Sichuan Basin
[J].
川中遂宁地区红层地下水水化学特征及主要离子来源分析
[J].
Synergistic bioleaching of chalcopyrite and bornite in Acidithiobacillus ferrivorans YL15 and electrochemical study at low temperature
[J].
低温下YL15对黄铜矿和斑铜矿的协同浸出及电化学研究
[J].
The influence of the electronic structure of solids on the anodic dissolution and leaching of semiconducting sulphide minerals
[J].
Influence of pH on persulfate oxidation of TCE at ambient temperatures
[J].In situ chemical oxidation (ISCO) is a technology used for groundwater remediation. This laboratory study investigated the use of the oxidant sodium persulfate for the chemical oxidation of trichloroethylene (TCE) at near ambient temperatures (10, 20 and 30 degrees C) to determine the influence of pH (pH=4, 7 and 9) on the reaction rate (i.e., pseudo-first-order rate constants) over the range of temperatures utilized. TCE solutions (60 mg l(-1); 0.46 mM) were prepared in phosphate buffered RO water and a fixed persulfate/TCE molar ratio of 50/1 was employed in all tests. Half-lives of TCE degradation at 10, 20 and 30 degrees C (pH 7) were 115.5, 35.0 and 5.5h, respectively. Maximum TCE degradation occurred at pH 7. Lowering system pH resulted in a greater decrease in TCE degradation rates than increasing system pH. Radical scavenging tests used to identify predominant radical species suggested that the sulfate radical (SO(4)(.-)) predominates under acidic conditions and the hydroxyl radical (.OH) predominates under basic conditions. In a side by side comparison of TCE degradation in a groundwater vs. unbuffered RO water it was demonstrated that when the system pH is buffered to near neutral pH conditions due to the presence of natural occurring groundwater constituents that the TCE degradation rate is higher than in unbuffered RO water where the system pH dropped from 5.9 to 2.8. The results of this study suggest that in a field application of ISCO, pH should be monitored and adjusted to near neutral if necessary.
Electrochemical performance of sacrificial anodes in alternating depth and shallowness of seawater environments
[J].
深浅交变环境牺牲阳极电化学性能研究
[J].在前期研究工作基础上,在Al-Zn-Ga-Si低电位牺牲阳极材料中分别添加Sn、Bi、Ti、Sb等合金元素改善阳极综合性能。通过常规海水环境中的电化学性能测试,在制备的多种阳极材料中遴选出符合要求的低驱动电位牺牲阳极材料。将遴选出的综合电化学性能良好的Al-Zn-Ga-Si-Sb阳极进行模拟深浅海交变环境电化学性能测试,考察Sb含量对阳极电化学性能影响;采用三维视频和宏观表征来分析Sb对溶解形貌的影响。实验结果表明,添加适量Sb可以促进阳极材料的均匀活化溶解,提高复杂环境下阳极活化性能,并减少局部腐蚀的作用,当Sb含量为0.5% (质量分数) 时阳极综合电化学性能良好,满足高强钢阴极保护准则要求,可进一步开发Al-Zn-Ga-Si-0.5Sb牺牲阳极在深浅海交变环境下的高强钢阴极保护应用。
Influence of ultraviolet light irradiation on the corrosion behavior of carbon steel AISI 1015
[J].
Role of the oxide layer in radiation-induced corrosion of copper in anoxic water
[J].
A study of accelerated corrosion of stainless steels under highly oxidizing conditions
[J].
Advances on determination methods of free radicals in advanced oxidation processes
[J].
高级氧化技术中自由基的检测技术和方法研究进展
[J].
Photodegradation of methylene blue and methyl orange with CuO supported on ZnO photocatalysts: the effect of copper loading and reaction temperature
[J].
Staged assessment for the involving mechanism of humic acid on enhancing water decontamination using H2O2-Fe(III) process
[J].
Insights into the role of in-situ and ex-situ hydrogen peroxide for enhanced ferrate(VI) towards oxidation of organic contaminants
[J].
Hydroxyl radicals in anodic oxidation systems: Generation, identification and quantification
[J].
Intensifying the desulfurization of high-sulfur bauxite byexternal field and the mechanism of oxidation of pyrite by hydroxyl radicals
[D].
羟基自由基氧化黄铁矿及外场强化高硫铝土矿电解脱硫机理
[D].
Water oxidation on TiO2: A comparative DFT study of 1e-, 2e-, and 4e- processes on rutile, anatase, and brookite
[J].
Filtrates with hydroxyl radicals prepared using Al + Acid + H2O2 for removing organic pollutants
[J].
On the mechanism of γ-radiation-induced corrosion of copper in water
[J].
Synergistic corrosion inhibition effect of a compound inhibitor for aluminum
[J].
金属铝用复配缓蚀剂协同缓蚀作用研究
[J].采用理论模拟与实验分析方法,将4-巯基吡啶(4MP)、十二烷基硫酸钠(SDS)和4MP-SDS复配缓蚀剂作为金属铝缓蚀剂,对其在3.5% (质量分数)NaCl溶液中的缓蚀行为进行了研究。结果表明,加注缓蚀剂可有效降低自腐蚀电流密度,缓蚀剂加注浓度提高对改善缓蚀剂脱附电位具有促进作用,缓蚀效率顺序为4MP + SDS > SDS > 4MP,失重测试结果与电化学测试结果表现出较好的一致性。复配缓蚀剂加注后,可在金属表面吸附形成缓蚀剂膜层,增大腐蚀性离子扩散和迁移的阻力,样品腐蚀速率减慢,表面维持较好的金属光泽,表现出均匀腐蚀形态特征。
Inhibition action of machilus yunnanensis leaves extract on corrosion of Al-plate in HCl medium
[J].
滇润楠叶提取物对铝在HCl中的缓蚀性能
[J].采用失重法、电化学法、电感耦合等离子发射光谱仪(ICP-OES)、金相显微镜、扫描电子显微镜(SEM)及接触角测试研究了滇润楠叶提取物(MYLE)在1.0 mol·L<sup>-1</sup> HCl溶液中对Al的缓蚀性能。结果表明:20℃时,1000 mg·L<sup>-1</sup> MYLE的最大缓蚀率可达93.5%,MYLE浓度越高,缓蚀性能越强;而温度越高,缓蚀性能越弱。MYLE在Al表面的吸附主要以化学吸附为主,在低温时符合Langmuir吸附等温式,高温时符合Freundlich吸附等温式。Al在添加MYLE前后的HCl中腐蚀动力学规律符合Arrhenius公式和过渡态理论方程,添加MYLE后表观活化能(E<sub>a</sub>)、指前因子(A)、表观活化焓(ΔH<sub>a</sub>)、表观活化熵(ΔS<sub>a</sub>)均增大。MYLE为混合型缓蚀剂,其电化学缓蚀作用机理为“几何覆盖效应”,Nyquist图主要由高频区的容抗弧和低频区的感抗弧组成,且随着MYLE浓度增大,电荷转移电阻和电感电阻均增大。添加MYLE后,缓蚀体系中Al<sup>3+</sup>浓度明显降低,SEM观察进一步证实了MYLE有效减缓了Al表面的腐蚀程度。
Effect of free radicals generated by UV and semiconductor corrosion products on the inhibition behaviour of Ce3+
[J].
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