Adenine-based ionic liquid as an inhibitor for 316L stainless steel corrosion in simulated industrial cooling water: experimental and theoretical investigations

Abstract

Purpose This study aims to evaluate the corrosion inhibition effect of a synthesized organic ionic liquid, namely, 9,6-di-tris(2-hydroxyethyl)ammonium purin-6-amine (TEAA), on 316L stainless steel (316L SS) substrate in simulated industrial cooling water at hydrodynamic conditions. Design/methodology/approach The investigation was carried out by combining electrochemical measurements with theoretical analysis. Potentiodynamic polarization curves were used to characterize the electrochemical behavior, while electrochemical impedance spectroscopy was used to assess the resistance characteristics. Additionally, quantum chemical calculations based on density functional theory (DFT) and molecular dynamics simulations were conducted to elucidate the adsorption mechanism. Findings TEAA exhibits anodic-type inhibition of 316L SS corrosion, significantly reducing anodic current density and increasing polarization resistance, with a maximum efficiency of 92.7% at 10−3 M. Its performance improves over time, reaching 97.47% after eight days, due to the formation of a protective film on 316L SS surface. Theoretical studies confirm mixed adsorption interactions, with DFT identifying N=C, –N and –O as key adsorption sites, and MD simulations validating strong and stable adsorption on the 316L SS surface. Originality/value This work presents a comprehensive electrochemical and theoretical assessment of TEAA as an effective corrosion inhibitor for 316L SS in simulated industrial cooling water environments. The combined experimental–computational approach offers in-depth understanding of the hybrid adsorption mechanism and highlights TEAA’s strong affinity for the 316L SS surface, confirming its potential as a stable and efficient inhibitor under prolonged exposure conditions. In addition, the main advantage of TEAA for corrosion inhibition lies in its high adsorption efficiency, tunability, thermal stability and low volatility, making it more effective and environmentally friendly compared to many traditional inhibitors.