Development of amine-based filming corrosion inhibitors for industrial water treatment

Abstract

This study addresses the synthesis and performance validation of a novel organic corrosion inhibitor formulated with film-forming amines (FFA) for carbon steel protection in industrial water circuits. To overcome inherent solubility limitations of long-chain hydrophobic amines, the formulation matrix was stabilized using tallow amines as co-surfactants. Microstructural characterization via SEM-EDX revealed that, in the absence of treatment, iron oxide layers develop with thicknesses of up to 298 μm. In contrast, the application of the optimized FFA treatment prevents the accumulation of these corrosion products and promotes the formation of a compact protective film approximately 8 μm thick. Under high corrosive stress (Ryznar Stability Index, RSI = 15), batch testing demonstrated that the FFA formulation sustained steady-state corrosion rates below 0.30 mpy up to day 10, significantly outperforming untreated controls (> 30 mpy) and meeting NACE excellence criteria. Long-term performance verified in a pilot plant under continuous recirculation for three months yielded a mean corrosion rate of 0.153 ± 0.018 mpy, establishing the industrial feasibility and robustness of this protective inhibitor film.