Experimental and Theoretical Studies of Salsola oppositifolia Extract as a Novel Eco-Friendly Corrosion Inhibitor for Carbon Steel in 3% NaCl

This study used an extract from Salsola oppositifolia as an environmentally friendly and sustainable corrosion inhibitor for St20 carbon steel in a 3% NaCl solution. The experimental findings were corroborated through computational methods. The corrosion-inhibiting properties of the extract were evaluated using weight loss measurements and electrochemical potentiodynamic polarization, alongside surface analysis conducted via SEM (Scanning Electron Microscopy) and AFM (Atomic Force Microscopy). The weight loss measurements and electrochemical experiments demonstrated that the Salsola oppositifolia extract acted as an effective corrosion inhibitor. The efficiency of corrosion inhibition increased with higher concentrations of the plant extract, exceeding 93.82% at concentrations of 400, 600, and 1000 mg L-1. This notable inhibitory performance was attributed to the extract's strong adsorption onto the steel surface and its mixed-type behaviour, with adsorption data fitting well into the Langmuir isothermal model. Further investigations at an optimal concentration and immersion time of 240 hours indicated the stability of the adsorbed inhibitor layer on the St20 surface in 3% NaCl media.