海洋环境腐蚀与生物污损重点实验室知识库

近岸海域的无机氮、重金属离子污染不仅对海水生态系统的平衡造成破坏，还可作为环境因素，对海洋中服役钢结构的腐蚀过程产生影响。开展海洋污染物对金属材料腐蚀影响的研究工作具有重要价值，不仅能更全面地认识到环境因素对腐蚀过程的复杂影响，还能为相关防腐措施提供新的设计思路。为此，本论文分别研究了以下三种典型海洋污染物：硝酸盐、铜离子、锌离子对船舶制造业常用的EH40钢腐蚀行为的影响。同时通过电化学测试、表面分析及高通量测序等技术手段，解析硝酸盐、铜离子、锌离子影响EH40钢腐蚀的作用机制。主要的研究结果如下：

（1）探讨了海水中硝酸盐的添加对EH40钢的腐蚀促进机制。搭建了添加0 mmol·L^-1、0.1 mmol·L^-1、1 mmol·L^-1、10 mmol·L^-1、100 mmol·L^-1硝酸盐的室内模拟海水全浸区挂片实验体系，研究了EH40钢在其中的腐蚀过程。12周的浸泡实验结果显示，硝酸盐的添加增大了EH40钢的腐蚀失重，且腐蚀促进作用具有浓度依赖性（腐蚀失重变化规律：添加0 mmol·L^-1≈添加0.1 mmol·L^-1<添加1 mmol·L^-1<添加10 mmol·L^-1≈添加100 mmol·L^-1）。硝酸盐的添加对EH40钢腐蚀的影响经由微生物起作用，然而其对海水中游离微生物的数量并无显著影响，而是改变了EH40钢表面微生物的群落结构。硝酸盐能够选择性的刺激微生物群落中具有硝酸盐还原能力细菌的生长，改变群落中硝酸盐还原菌属（Ralstonia、Sulfurimonas、Thiomicrospira、Pseudomonas）的相对丰度及种类分布，或将形成腐蚀性更强的微生物群落，进而促进EH40钢的腐蚀过程。

（2）揭示了海水中铜离子的添加对EH40钢的腐蚀促进机制。构建了添加0 mmol·L^-1、1.5 mmol·L^-1、15 mmol·L^-1铜离子的实验室模拟海水全浸区挂片实验体系，进行4周的EH40钢腐蚀浸泡实验。结果发现，铜离子的添加明显促进EH40钢的腐蚀过程，且添加15 mmol·L^-1铜离子时的促进作用较强。此外，添加铜离子海水中的EH40钢表面腐蚀产物出现特殊分层现象，均覆盖铜单质层和Fe₃O₄层。铜离子可通过以下三方面促进腐蚀：（a）铜离子在海水中发生水解反应，导致海水pH值明显下降，形成更严苛的酸性腐蚀环境；（b）铜离子和EH40钢发生置换反应生成铜单质，直接消耗EH40钢的铁基体；（c）生成的铜单质层覆盖在EH40钢表面，通过导电性良好的Fe₃O₄层与EH40钢基体形成电偶腐蚀池，将显著加剧阳极铁的腐蚀溶解。

（3）提出了海水中锌离子的添加对EH40钢的腐蚀抑制机制。搭建了添加0 mmol·L^-1、1.5 mmol·L^-1、15 mmol·L^-1锌离子的模拟海水全浸区挂片实验体系，进行4周的EH40钢浸泡实验。发现锌离子的添加虽然在一定程度上加剧了EH40钢的局部腐蚀，但整体上仍为腐蚀抑制趋势，且添加15 mmol·L^-1锌离子时的抑制作用更强。锌离子主要通过以下两个方面抑制EH40钢的腐蚀过程：（a）在EH40钢表面覆盖由六边形ZnO薄片堆积而成的保护性膜层，能够减轻EH40钢的腐蚀损伤；（b）锌离子和ZnO都具有良好的抗菌性，可在一定程度上减轻EH40钢因微生物腐蚀造成的损失。

The pollution of inorganic nitrogen and heavy metal ions in coastal waters not only destroys the balance of seawater ecosystem, but also affects the corrosion process of steel structures in service as environmental factors in marine. It is of great value to carry out research on the influence of marine pollutants on the corrosion of metal materials, which can not only more comprehensively understand the complex influence of environmental factors on the corrosion process, but also provide new design ideas for relevant corrosion prevention measures. In this thesis, the effects of three typical marine pollutants: nitrate, copper ions and zinc ions on corrosion behavior of EH40 steel commonly used in shipbuilding industry were studied. At the same time, the mechanism of nitrate, copper ions and zinc ions affecting corrosion of EH40 steel was analyzed by electrochemical test, surface analysis and high-throughput sequencing technology. The main results are as follows:

(1) The corrosion promoting mechanism of EH40 steel by addition of nitrate in seawater was discussed. The corrosion process of EH40 steel in a simulated seawater immersion zone with 0 mmol·L^-1, 0.1 mmol·L^-1, 1 mmol·L^-1, 10 mmol·L^-1 and 100 mmol·L^-1 nitrate was studied. The results of 12-week immersion experiment showed that the addition of nitrate increased the corrosion weight loss of EH40 steel, and the corrosion promoting effect was concentration-dependent (the change rule of corrosion weight loss was: add 0 mmol·L^-1 ≈ add 0.1 mmol·L^-1 < add 1 mmol·L^-1 < add 10 mmol·L^-1 ≈ add 100 mmol·L^-1). The effects of nitrate addition on corrosion of EH40 steel was influenced by microorganisms. However, the addition of nitrate did not significantly affect the number of free microorganisms in seawater, but changed the community structure of microorganisms on the surface of EH40 steel. Nitrate can selectively stimulate the growth of nitrate-reducing bacteria in the microbial community, change the relative abundance and species distribution of nitrate-reducing bacteria (Ralstonia, Sulfurimonas, Thiomicrospira, Pseudomonas) in the community, or form a more corrosive microbial community, thus promoting the corrosion process of EH40 steel.

(2) The corrosion promotion mechanism of EH40 steel with the addition of copper ions in seawater is revealed. The experimental system of adding 0 mmol·L^-1, 1.5 mmol·L^-1 and 15 mmol·L^-1 copper ions in simulated seawater immersion area was constructed, and the corrosion immersion experiment of EH40 steel was carried out for 4 weeks. The results showed that the addition of copper ions significantly promoted the corrosion process of EH40 steel, and the effect of adding 15 mmol·L^-1 copper ions was stronger. In addition, the corrosion products on the surface of EH40 steel immersed in seawater with the addition of copper ions appeared special stratification phenomenon, which all covered with copper elemental layer and Fe₃O₄ layer. Copper ions can promote corrosion through the following three aspects: (a) Copper ions in seawater hydrolysis reaction, resulting in a significant decline in seawater pH value, the formation of a more severe acidic corrosive environment; (b) Copper ions and EH40 steel undergo displacement reaction to generate copper elemental substance, which directly consumes the iron matrix of EH40 steel; (c) The generated copper elemental layer covers the surface of the EH40 steel, and through the Fe₃O₄ layer with good electrical conductivity and the substrate of the EH40 steel, the galvanic corrosion pool is formed, which will significantly intensify the corrosion dissolution of the anode iron.

(3) The corrosion inhibition mechanism of the addition of zinc ions in seawater on EH40 steel is proposed. The experimental system was set up with 0 mmol·L^-1, 1.5 mmol·L^-1 and 15 mmol·L^-1 zinc ions in the simulated seawater immersion area, and the immersion experiment of EH40 steel was carried out for 4 weeks. It was found that although the addition of zinc ions intensified the local corrosion of EH40 steel to some extent, the corrosion inhibition trend was still on the whole, and the inhibition effect was stronger when adding 15 mmol·L^-1 zinc ions. The corrosion process of EH40 steel is mainly inhibited by zinc ions in the following two aspects: (a) The corrosion damage of EH40 steel can be reduced by covering the surface of EH40 steel with a protective film composed of hexagonal ZnO sheets; (b) Both zinc ions and ZnO have good antibacterial properties, which can reduce the loss caused by microbial corrosion of EH40 steel to a certain extent.

第1章  绪论.... 1

1.1  引言... 1

1.2  海洋腐蚀概述... 2

1.2.1  海洋腐蚀特征及类别... 2

1.2.2  影响海洋腐蚀的主要环境因素... 4

1.3  海洋污染物概述... 5

1.3.1  典型海洋污染物... 5

1.3.2  典型海洋污染物影响腐蚀的研究进展... 8

1.4  研究意义及研究思路... 12

1.4.1  研究意义... 12

1.4.2  研究思路... 13

第2章  实验方案... 15

2.1  实验材料及试剂... 15

2.1.1  实验材料... 15

2.1.2  实验试剂... 16

2.2  实验方法... 16

2.2.1  浸泡实验... 16

2.2.2  腐蚀失重测试... 18

2.2.3  腐蚀电化学测试... 18

2.2.4  腐蚀形貌分析... 18

2.2.5  腐蚀产物成分分析... 19

2.2.6  生物膜分析... 19

2.2.7  表面微生物群落分析... 19

第3章  天然海水中硝酸盐的添加对EH40钢腐蚀的影响... 21

3.1  研究背景... 21

3.2  硝酸盐的添加对EH40钢腐蚀失重的影响... 21

3.3  硝酸盐的添加对EH40钢电化学行为的影响... 22

3.4  硝酸盐的添加对EH40钢腐蚀形貌的影响... 23

3.5  硝酸盐的添加对EH40钢腐蚀产物成分的影响... 27

3.6  硝酸盐的添加对EH40钢生物膜的影响... 28

3.7  硝酸盐的添加对灭菌海水中EH40钢腐蚀失重的影响... 29

3.8  硝酸盐的添加对EH40钢表面微生物群落结构的影响... 30

3.9  硝酸盐的添加对海水环境因子的影响... 34

3.10  硝酸盐的添加影响EH40钢腐蚀的机制... 34

3.11  本章小结... 36

第4章  天然海水中铜离子的添加对EH40钢腐蚀的影响... 37

4.1  研究背景... 37

4.2  铜离子的添加对EH40钢腐蚀失重的影响... 37

4.3  铜离子的添加对EH40钢电化学行为的影响... 38

4.4  铜离子的添加对EH40钢腐蚀形貌的影响... 42

4.5  铜离子的添加对EH40钢腐蚀产物成分的影响... 45

4.6  铜离子的添加对EH40钢生物膜的影响... 48

4.7  铜离子的添加对海水环境因子的影响... 49

4.8  铜离子的添加影响EH40钢腐蚀的机制... 51

4.9  本章小结... 52

第5章  天然海水中锌离子的添加对EH40钢腐蚀的影响... 53

5.1  研究背景... 53

5.2  锌离子的添加对EH40钢腐蚀失重的影响... 53

5.3  锌离子的添加对EH40钢电化学行为的影响... 54

5.4  锌离子的添加对EH40钢腐蚀形貌的影响... 58

5.5  锌离子的添加对EH40钢腐蚀产物成分的影响... 62

5.6  锌离子的添加对EH40钢生物膜的影响... 63

5.7  锌离子的添加对海水环境因子的影响... 65

5.8  锌离子的添加影响EH40钢腐蚀的机制... 67

5.9  本章小结... 68

第6章  结论与展望... 69

6.1  结论... 69

6.2  创新点... 70

6.3  展望... 70

参考文献... 71

致  谢... 81

作者简历及攻读学位期间发表的学术论文与研究成果    83