Anticorrosive properties of novel green inhibitor based on Euphorbia resinifera latex for C38 steel in acid environment

Steel corrosion is a major challenge in industrial applications, requiring effective and sustainable solutions. This study investigates the potential of an aqueous extract from Euphorbia resinifera latex (ERLE) as a green corrosion inhibitor for C38 carbon steel in a 1 M HCl solution. The extract was obtained by macerating the plant’s aerial parts and characterized using gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization confirmed ERLE’s inhibitory action, while UV-Vis spectroscopy and scanning electron microscopy (SEM) provided insights into adsorption mechanisms. ERLE was found to be rich in polyphenols, sesquiterpenes, and oxidized terpenes, with functional groups (-OH, -COO) contributing to its anticorrosive properties. XRD analysis revealed an amorphous structure that facilitated protective surface deposits, reducing Cl⁻ and H₃O⁺ ion transfer. The TGA/DSC results demonstrated the extract’s thermal stability and an inhibition efficiency of 73 % was achieved at just 0.75 g/L, indicating a cathodic-type inhibition mechanism. Adsorption followed the Langmuir isotherm, suggesting physisorption as the dominant interaction. Compared to conventional inhibitors, ERLE offers an eco-friendly alternative with promising industrial applications. Further studies can explore its long-term stability in real-world conditions and assess its effectiveness across various industrial sectors to expand its potential use as a sustainable corrosion inhibitor. • PDP analysis indicates that the inhibitor functions as a cathodic inhibitor. • SEM-EDX, UV-Vis analysis revealed spherical structures formed on the metal surface. • FTIR analysis yielded distinct bands indicative of the O-H, C=O, and C-O bonds. • XRD analysis demonstrated that the extract possesses an amorphous structure. • TGA-DSC analysis indicates that the extract exhibits moderate thermal stability.