Istanbul University, Institute of Marine Sciences and Management, 34134, Vefa, Istanbul, Turkey; Istanbul University, Faculty of Science, Department of Biology, 34134, Vezneciler, Istanbul, Turkey.
Yildiz Technical University, Faculty of Chemistry-Metallurgy, Metallurgical and Materials Engineering Department, 34210, Esenler, Istanbul, Turkey.
Bioelectrochemistry. 2022 Aug;146:108143. doi: 10.1016/j.bioelechem.2022.108143. Epub 2022 Apr 26.
In this study, the biofilms at different ages formed on galvanized steel coupons in a simulating cooling tower water system were exposed to the Ag-Cu ions over 504 h and the changes in the structure of the biofilms were investigated using electrochemical, microbiological, and surface analyses. The effect of the Ag-Cu ions on the structure of the natural biofilm during the maturation process was evaluated for the first time in this study. Exposure to Ag-Cu ions changed the structure of the biofilm, reducing the concentration of carbohydrates in EPS, causing the shedding from the biofilm by disrupting/making weakening the integrity of the biofilm. After exposure to Ag-Cu ions, the biofilm turned into a heterogeneous, fissured-porous and sandy structure. In addition, in the absence of the ions and after exposure to the ions, the MIC behavior of galvanized steel with natural biofilm at different ages was evaluated using electrochemical and gravimetric tests. It was determined that the galvanized steel suffered to MIC and exposure to Ag-Cu ions increased the corrosion rate of it. Therefore, using of Ag-Cu ions at maximum concentration values (0.1 ppm Ag and 1.3 ppm Cu) suggested by EPA is not recommended to prevent MIC problem in cooling tower systems.
在这项研究中，将在模拟冷却塔水中系统中形成于镀锌钢试片上的不同年龄的生物膜暴露于 Ag-Cu 离子中超过 504 小时，并使用电化学、微生物学和表面分析来研究生物膜结构的变化。本研究首次评估了 Ag-Cu 离子对成熟过程中天然生物膜结构的影响。暴露于 Ag-Cu 离子会改变生物膜的结构，降低 EPS 中碳水化合物的浓度，通过破坏/削弱生物膜的完整性导致生物膜脱落。暴露于 Ag-Cu 离子后，生物膜变成了一种不均匀、有裂缝的多孔和沙质结构。此外，在没有离子存在的情况下以及暴露于离子之后，使用电化学和重量测试评估了具有不同年龄的天然生物膜的镀锌钢的 MIC 行为。确定镀锌钢遭受 MIC 并且暴露于 Ag-Cu 离子会增加其腐蚀速率。因此，不建议按照 EPA 建议的最大浓度值（0.1ppmAg 和 1.3ppmCu）使用 Ag-Cu 离子来防止冷却塔系统中的 MIC 问题。
