Corrosion resistance and antibacterial activity of 2-mercaptobenzothiazole for 7B04 aluminium alloy in 3.5%NaCl solution

Abstract

In this paper, the inhibition effect of 2-mercaptobenzothiazole (MBT) on microorganisms in the fuel system and corrosion inhibition of 7B04 aluminum alloy are studied, and the mechanism is discussed. The antibacterial activity of MBT is studied by microbial experiments. The agar diffusion test demonstrates the significant antibacterial efficacy of MBT against Lysinibacillus sphaericus (L. sphaericus) and Acinetobacter lwoffii (A. lwoffii) strains isolated from aircraft fuel systems, and the bacteriostatic effect on L. sphaericus is better. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PDP) results show that MBT inhibits the corrosion of 7B04 aluminum alloy by forming a protective film on the aluminum alloy surface and inhibiting the cathode reaction. In this study, the most effective corrosion inhibition concentration of MBT is 200 mg∙L−1, with a maximum corrosion inhibition rate of 99.27%. Langmuir adsorption isotherm results further indicate that MBT acts on the aluminum alloy surface by physical adsorption and chemical adsorption. The scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) results confirm that MBT form a protective adsorption film on the aluminum alloy surface, which effectively shield the corrosive media on the surface. Furthermore, density functional theory (DFT), Monte Carlo simulation (MC), and molecular dynamics simulation (MD) are employed to identify the active sites of MBT as N and S atoms and to demonstrate that MBT adsorb onto the aluminum alloy surface in a horizontal orientation.