Abstract Metallic corrosion is a major issue that leads to an efficiency loss and eventual failure of the system in geothermal power plants. Despite the growing understanding of mechanisms of corrosion, inhibiting steel corrosion in the acidic geothermal fluids, remains to present formidable challenges due to its intrinsic physicochemical complexity. Here, we study the use of nanobubbles as a possible corrosion inhibitor by testing alteration of the low-carbon steel plates immersed in acidic geothermal water with continuously injected air-nanobubbles. Nanobubbles have been used in a broad range of areas as they are eco-friendly, low-cost, easy-to-use and high-functional materials. We, for the first time to our knowledge, found that air-nanobubbles could inhibit steel corrosion, with inhibition efficiency of up to 50 % in the studied acidic geothermal fluid. Air-nanobubbles could act as a nanoscopic coating material in the acidic geothermal fluid, through generating a bubble mattress and/or promoting nucleation and aggregation of a very small quantity of silica precipitation on the surface of steel plates. Our finding suggests that nanobubbles can inhibit steel corrosion in various chemically different geothermal fluids, highlighting the physicochemical significance of nanobubbles as the coating material for inhibiting metal degradation in the geothermal infrastructures.

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纳米气泡作为酸性地热流体中的缓蚀剂

摘要 金属腐蚀是导致地热发电厂系统效率损失和最终故障的主要问题。尽管对腐蚀机制的了解越来越多，但由于其固有的物理化学复杂性，在酸性地热流体中抑制钢腐蚀仍然面临着巨大的挑战。在这里，我们通过测试浸入酸性地热水中的低碳钢板与连续注入的空气纳米气泡的变化来研究纳米气泡作为可能的腐蚀抑制剂的用途。纳米气泡是一种环保、低成本、易于使用和高功能的材料，已被用于广泛的领域。据我们所知，我们第一次发现空气纳米气泡可以抑制钢腐蚀，在研究的酸性地热流体中抑制效率高达 50%。空气纳米气泡可以作为酸性地热流体中的纳米涂层材料，通过产生气泡垫和/或促进钢板表面极少量二氧化硅沉淀的成核和聚集。我们的发现表明，纳米气泡可以抑制各种化学性质不同的地热流体中的钢铁腐蚀，突出了纳米气泡作为抑制地热基础设施中金属降解的涂层材料的物理化学意义。通过产生气泡垫和/或促进钢板表面极少量二氧化硅沉淀的成核和聚集。我们的发现表明，纳米气泡可以抑制各种化学性质不同的地热流体中的钢铁腐蚀，突出了纳米气泡作为抑制地热基础设施中金属降解的涂层材料的物理化学意义。通过产生气泡垫和/或促进钢板表面极少量二氧化硅沉淀的成核和聚集。我们的发现表明，纳米气泡可以抑制各种化学性质不同的地热流体中的钢铁腐蚀，突出了纳米气泡作为抑制地热基础设施中金属降解的涂层材料的物理化学意义。