Synergistic inhibition behavior between rhodamine blue and cationic gemini surfactant on mild steel corrosion in 1 M HCl medium

Abstract

This paper describes corrosion resistance action of Rhodamine blue (RhB) dye in the presence of gemini surfactant (GS) namely, 1,2-ethanediyl-bis(dimethyldecylammonium bromide), (referred to as 10-2-10, where 10 and 2 is the count of carbon atoms in alkyl chain and the spacer part, respectively) for mild steel (MS) in 1 M HCl medium. A combination of experimental and theoretical studies such as mass loss, potentiodynamic polarization method, electrochemical impedance spectroscopy, Ultraviolet-visible (UV-Vis) analysis, Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and molecular dynamic (MD) simulations study were used to investigate the inhibiting features of investigated compounds. Individual RhB and 10-2-10 GS showed low to moderate inhibition efficiency, however, inhibition efficacy of RhB was substantially increased at all studied concentrations when it was synergized with a minimum concentration of 10-2-10 GS (1 × 10−6 M). RhB (1 × 10−3 M) and 10-2-10 (1 × 10−6 M) mixed system offered the highest resistance to acid corrosion (97.5%) at 30°C. MD simulation method evidenced the binding of the studied system onto the MS surface.