Anticorrosive efficacy of saponin and sodium dodecyl sulfate on mild steel specimens immersed in acidic medium

Mild steel corrosion in acidic environments poses a significant challenge for industrial sectors, leading to the degradation of metallic materials and elevated maintenance costs. This research aims to explore the mitigation of corrosion using a combination of a naturally occurring plant-based saponin and a widely used synthetic surfactant, such as sodium dodecyl sulfate (SDS). The inhibition performance was studied in 0.5 M H2SO4 utilizing a weight loss study, an electrochemical polarization study, and a microscopic surface study. The combined mixture of saponin-SDS shows superior performance to the individual inhibitor. A weight loss study confirmed that saponin shows 64.30% efficiency at 2.92 g/L, but it is increased by 13.35–77.66% with the addition of SDS. Similarly, the electrochemical polarization study confirmed 96.70% inhibition efficiency with a mixed system, with the lowering of both current densities. This study confirmed physical adsorption of surfactants onto the immersed steel surface, forming a protective film. The improvement in surface coverage and strong interactions between SDS and immersed metal specimens are due to the amphiphilic behaviour of saponin. Also, the synergistic inhibition effect of natural and synthetic surfactants becomes an environmentally benign and effective corrosion inhibitor. This output becomes a prominent tool to develop greener and more sustainable strategies for industrial applications.