Research on the Corrosion Inhibition Behavior and Mechanism of 1-Hydroxy-1,1-ethyledine Disodium Phosphonate under an Iron Bacteria System

Regenerated water serves as a supplementary source for circulating cooling water systems, but it often fosters microbial growth within pipelines. Given its widespread use as a corrosion inhibitor, understanding HEDP’s efficacy in microbial environments and its impact on microorganisms is imperative. This study established an iron bacterial system by isolating and enriching iron bacteria. Through a comprehensive approach incorporating corrosion weight loss analysis, XPS analysis, SEM electron microscopy, as well as microbial and electrochemical testing, the corrosion inhibition behavior and mechanism of HEDP within the iron bacterial system were investigated. The findings reveal that within the iron bacterial system, HEDP achieves a corrosion inhibition rate of 76% following four distinct stages—weakening, strengthening, stabilizing, and further strengthening—underscoring its robust corrosion inhibition capability. Moreover, HEDP enhances the density of biofilms and elevates the activation energy of carbon steel interfaces. It alternates with oxygen to continuously suppress the activity of IRB while gradually inhibiting the activity of IOB. This process culminates in a corrosion inhibition mechanism where cathodic inhibition predominates, supported by anodic inhibition as a complementary mechanism.