Enhancing metal corrosion inhibition with xanthan gum: The synergistic role of anionic surfactants

The effects of sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) on the corrosion inhibition of xanthan gum (XG) on Q235 carbon steel were investigated. The corrosion inhibition performance was characterized by weight loss, kinetic potential polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and ultraviolet-visible spectroscopy (UV–vis) measurements. XG significantly reduced the corrosion rate of Q235 steel in HCl solution, and the corrosion rate decreased with increasing XG concentration. XG acted as a mixed inhibitor to inhibit corrosion by forming a protective adsorption layer on the metal surface. At a fixed SDS concentration, the XG/SDS mixture showed enhanced corrosion inhibition with increasing XG concentration, indicating that SDS had a synergistic effect on the corrosion inhibition of XG. In contrary, SDBS showed different behaviors in affecting the corrosion inhibition of XG. SDBS showed a synergistic effect on the corrosion inhibition at low XG concentrations, whilst further increasing XG concentration would not lead to a decreased anticorrosion performance. Structural variation in the adsorbed film formed by the XG/surfactant mixture on the metal surface is responsible for the anticorrosion performance. The study probes into the synergistic effects of surfactant on the ability of xanthan gum for metal corrosion inhibition, which is helpful for the development of more efficient and sustainable polymer/surfactant mixed corrosion inhibitors.