摘要
目的研究微生物活性与船用钢DH32腐蚀行为之间的关系,并通过胞外分泌物的提取,研究分泌物浓度对材料腐蚀性能的影响。方法通过傅里叶红外光谱(FT–IR)分析胞外分泌物的组成,通过电感耦合等离子体发射光谱仪(ICP-OES)分析金属离子的含量,并使用用原子力显微镜(AFM)观测去除腐蚀产物后的表面形貌。结果通过电化学阻抗谱的拟合分析,短期内,EPS通过阻碍溶解氧的扩散抑制腐蚀速度,EPS浓度越高,效果越好,即实验初期试样腐蚀的速度与EPS浓度成反比。随着时间的延长,EPS浓度低的溶液中,其EPS络合金属离子的能力很快达到饱和,所以尽管其络合行为能促进试样的阳极溶解,但影响作用有限,此时起到主要影响的还是EPS抑制溶解氧扩散。对于浓度高的EPS溶液,其过量的EPS会促进EPS的官能团与材料表面更多的Fe^(2+)/Fe^(3+)离子键合,使得沉积的EPS保护层变得疏松失去隔离溶解氧的作用,进而加速试样腐蚀。结论海洋微生物胞外分泌物对船用钢腐蚀行为的影响与胞外分泌物的结构与浓度有关,随着浓度升高,EPS从抑制腐蚀变为加速腐蚀。
Objective To explore the relationship between bacterial activity and corrosion behavior of hull steel and research influences of concentration of extracellular polymeric substances （EPS） on corrosion. Methods Fourier transform infrared spectroscopy （FT–IR） and ICP-OES such as inductive coupling were used to analyze composition of EPS and content of iron ion. The morphology of corrosion products was analyzed by atomic force microscope （AFM）. Results The fitting analysis of electrochemical impendence showed that EPS inhibited corrosion by hindering scattering of dissolved oxygen, the greater the concentration, the better the effect. That is to say, the corrosion speed of specimen in the initial state was inversely proportional to the EPS concentration. Therefore, although its complexation effect could promote anodic dissolution of the specimen, its effect was limited. It was the mainly the EPS which inhibited scattering of dis-solved oxygen. For EPS solution of high concentration, excessive EPS could promote more bonding between functional group of EPS and Fe^2＋/Fe^3＋on material surface, as a result, the EPS protective film might become loose and be unable to separate the dissolved oxygen and thus accelerate corrosion of specimen. Conclusion Effects of EPS on corrosion of hull steel is relevant to structure and concentration of EPS. EPS changes from inhibiting corrosion to accelerating corrosion with the increase of concentration.
出处
《装备环境工程》
CAS
2018年第1期86-95,共10页
Equipment Environmental Engineering
基金
国家自然科学基金(51609133)
上海市自然科学基金(14ZR1419800)
上海市科学技术委员会科研计划项目(15dz1207102)
关键词
胞外分泌物
微生物腐蚀
电化学阻抗
海水
extracellular polymeric substances
microbially-influenced corrosion
electrochemical impendence
sea-water
作者简介
张燊（1993-）,男,上海人,硕士研究生,主要研究方向为海洋运输工程与防护.;通讯作者：郭娜（1983-）,女,山东人,博士,高级工程师,主要研究方向为海洋材料腐蚀与防护.
