Xu Dake, Li Yingchao, Gu Tingyue
Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.
College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, 100 Ping Le Yuan, Chaoyang District, Beijing 100124, China.
Bioelectrochemistry. 2016 Aug;110:52-8. doi: 10.1016/j.bioelechem.2016.03.003. Epub 2016 Mar 24.
Biocorrosion is also known as microbiologically influenced corrosion (MIC). Most anaerobic MIC cases can be classified into two major types. Type I MIC involves non-oxygen oxidants such as sulfate and nitrate that require biocatalysis for their reduction in the cytoplasm of microbes such as sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). This means that the extracellular electrons from the oxidation of metal such as iron must be transported across cell walls into the cytoplasm. Type II MIC involves oxidants such as protons that are secreted by microbes such as acid producing bacteria (APB). The biofilms in this case supply the locally high concentrations of oxidants that are corrosive without biocatalysis. This work describes a mechanistic model that is based on the biocatalytic cathodic sulfate reduction (BCSR) theory. The model utilizes charge transfer and mass transfer concepts to describe the SRB biocorrosion process. The model also includes a mechanism to describe APB attack based on the local acidic pH at a pit bottom. A pitting prediction software package has been created based on the mechanisms. It predicts long-term pitting rates and worst-case scenarios after calibration using SRB short-term pit depth data. Various parameters can be investigated through computer simulation.
生物腐蚀也被称为微生物影响腐蚀（MIC）。大多数厌氧性微生物影响腐蚀案例可分为两大类。第一类微生物影响腐蚀涉及非氧氧化剂，如硫酸盐和硝酸盐，它们在诸如硫酸盐还原菌（SRB）和硝酸盐还原菌（NRB）等微生物的细胞质中还原时需要生物催化作用。这意味着来自铁等金属氧化的细胞外电子必须穿过细胞壁进入细胞质。第二类微生物影响腐蚀涉及由产酸菌（APB）等微生物分泌的氧化剂，如质子。在这种情况下，生物膜提供了局部高浓度的、无需生物催化就具有腐蚀性的氧化剂。这项工作描述了一个基于生物催化阴极硫酸盐还原（BCSR）理论的机理模型。该模型利用电荷转移和传质概念来描述硫酸盐还原菌的生物腐蚀过程。该模型还包括一种基于点蚀底部局部酸性pH值来描述产酸菌侵蚀的机制。基于这些机制创建了一个点蚀预测软件包。它在使用硫酸盐还原菌短期点蚀深度数据进行校准后，预测长期点蚀速率和最坏情况。可以通过计算机模拟研究各种参数。
