Comparative study of CPC and SDS on corrosion of mild steel in acidic media

This study is related to the inhibiting effect of the surfactants sodium dodecyl sulphate (SDS) and cetyl pyridinium chloride (CPC) against corrosion in case of mild steel in an acidic environment. Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), and Atomic Force Microscopy (AFM) were used. It could be seen through FTIR that there were drastic differences in the values of the peaks due to the functional groups present in the MS surface. It could also be observed through the surface analysis that the use of SDS and CPC has resulted in the reduction of surface roughness. The value of roughness determined in 0.5 M H2SO4 acidic solution was observed to be from 5.9 nm to 27 nm for MS without surfactant treatment, which became −5.6 nm to 23.5 nm after treatment with SDS, while CPC‑treated samples showed a value of −4.5 nm to 17 nm. This clearly shows that CPC produces a smoother surface than SDS because of its pyridinium structure. Using Density Functional Theory (DFT), the method is used to analyse SDS and CPC adsorption properties on Fe(110) surfaces, as well as how CPC acts as an effective corrosion inhibitor.