The effect of alkyl chain on the corrosion inhibition of benzyldimethylammonium chloride in acidic environments

HH Zhu and LC Peng and SQ Zhang and ZX Xu and B Shang and N Lu and JD Chen and WP Li, JOURNAL OF MOLECULAR LIQUIDS, 413, 126051 (2024).

DOI: 10.1016/j.molliq.2024.126051

Incorporating quaternary ammonium salts (QAS) during pickling is an efficient and eco-friendly approach to mitigating metal corrosion. This study investigated the effectiveness of Benzyldimethylhexadecylammonium chloride (HDBAC) and Benzyldimethyltetradecylammonium chloride (TDBAC) in inhibiting the corrosion of Q235 steel in H2SO4, utilizing electrochemical methods, atomic force microscopy (AFM), scanning electron microscopy (SEM), and theoretical calculations. The electrochemical results demonstrated that compared with the blank impedance value of 40.68 Omega cm(2), HDBAC and TDBAC at 5 mM concentration showed impedance values of 997.69 Omega cm(2) and 676.17 Omega cm(2) at 298 K, indicating that they can effectively prevent the corrosion of Q235. SEM and AFM further showed the formation of a protective barrier film by HDBAC and TDBAC on the steel surface, effectively isolating it from the corrosive medium. Theoretical calculations further elucidated the mechanism by which these inhibitors create this protective barrier. The experiment also verified the hypothesis that the length of the hydrophobic chain of surfactants affects the adsorption behavior and the inhibition efficiency. When comparing their inhibitory effects at 5 mM concentrations, HDBAC exhibited superior performance (95.92 %) against Q235 in 0.5 M H2SO4, compared to TDBAC (94.09 %). These findings provide valuable insights for developing more effective and sustainable corrosion inhibitors for industrial applications.

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