Experimental and quantum studies on [BMIM] BF4 ionic liquid as corrosioninhibitor for mild steel in H2SO4 solution

Ionic liquids have attracted considerable attention in recent years. They are described as havingmany potential applications. In particular, they have been identified as powerful solvents forgreen synthesis, and electrically conducting fluids. Salts that are liquid at near-ambienttemperature are important for electric battery applications, and have been considered as sealantsdue to their very low vapor pressure [1, 2]. In this work the inhibition behavior of [BMIM]BF4(1-butyl-3-methyl imidazolium tetrafluoroborate) on mild steel corrosion in 0.5 M H2SO4 ascorrosive solution was evaluated by the weight loss, potentiodynamic polarization andelectrochemical impedance spectroscopy (EIS) techniques in the absence and presence ofdifferent concentrations of [BMIM]BF4. Surface analysis using energy dispersive X-ray (EDX)and scanning electron microscope (SEM) allowed us to clarify the mechanistic aspects andevaluate the relative inhibition efficiency. Density functional theory (DFT) calculations wereperformed to gain some insight into the interactions of [BMIM]BF4 with the St-37 mild steelssurface. Results obtained from experimental and quantum studies are in good agreements. Thiswork has shown that the [BMIM]BF4 has an desirable inhibition effect on St-37 mild steelcorrosion in corrosive solution.

Keywords:

Ionic liquid , Inhibition , Corrosion , Density functional theory (DFT)