New MOF-Based Corrosion Inhibitor for Carbon Steel in Acidic Media

In this research, we present a novel class of metal–organic framework-based corrosion inhibitor materials named as zeolitic imidazolate framework-8@{Mo₁₃₂} (ZIF-8@{Mo₁₃₂}) nano-structure as an efficient and green inhibitor in HCl solution. To this purpose, ZIF-8@{Mo₁₃₂} nano-structure is prepared via a convenient and excellent interaction of {Mo₁₃₂} and ZIF-8 surface using a versatile recipe. Afterward, the application of the mentioned organometallic nano-structure as a corrosion inhibitor for carbon steel in HCl solution was evaluated and was compared with pristine ZIF-8 performance. In this sense, surface observation, electrochemical impedance spectroscopy and polarization resistance were applied to study inhibitory action of both ZIF-8 and ZIF-8@{Mo₁₃₂}. Full factorial design of the experiments was also implemented to investigate the real operating variables including inhibitor concentration, immersion time and temperature affecting the inhibition efficiency (%IE). The obtained ANOVA analyses indicated that temperature is not very significant and effective parameter on inhibition efficiency for both inhibitors. On the other hand, the thermodynamic study revealed that chemisorption occurs during ZIF-8@{Mo₁₃₂} adsorption on the metal surface due to the high tendency of anionic ZIF-8@{Mo₁₃₂} inhibitor to absorb over steel surface. This observation was also confirmed by AFM and SEM images taken from the steel surface. It is also found that ZIF-8@{Mo₁₃₂} nano-structure demonstrated high activity as an effective corrosion inhibitor in HCl solution.