Withania somnifera extract (WSE) as eco-friendly corrosion inhibitor for Al in acidic solutions: Experimental and mathematical analyses

• M.M. El-Toony¹, A.M. Wahba^2,3 and A.S. Fouda⁴

¹ Chemistry Department, Faculty of Sciences and arts, King Khalid University, Tehama branch, Saudi Arabia
² Medical Sciences & Preparatory Year Department, North Private College of Nursing, Arar 73312, Northern Border Province, Saudi Arabia
³ Basic Science Department, Higher Institute of Engineering and Technology (HIET), El-Mahala EL-Kobra 31951, Egypt
⁴ Department of Chemistry, Faculty of Science, Mansoura University, Mansoura-35516, Egypt

Abstract: This study investigates the anticorrosion behavior of Withania somnifera extract (WSE) as a green inhibitor for Al in hydrochloric acid (HCl) solutions. The preparation of the plant extract involved extraction by dichloromethane. Mass loss measurements and electrochemical techniques were used to evaluate its efficacy. Results indicate a significant reduction in the corrosion rate of Al, with inhibition efficiency increasing with extract concentration, achieving up to 81.16% at 300 ppm. The adsorption behavior was analyzed, revealing a combination of physical and chemical interactions, with Gibbs free energy calculations indicating favorable adsorption processes. Surface examinations using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the formation of a protective layer on Al surfaces. Additionally, temperature variations were shown to influence the corrosion rate and inhibition efficiency. Additionally, machine learning techniques showed that Gradient Boosting Regression (GBR) outperformed K-Nearest Neighbors (KNN) and Support Vector Regression (SVR), with R² values from 0.923 to 0.982. Feature importance analysis indicated that inhibitor concentration was a key predictor across datasets. These findings suggest that Withania somnifera is a promising eco-friendly alternative for corrosion inhibition in acidic environments, promoting the use of natural compounds in industrial applications.

Keywords: adsorption, aluminum, corrosion inhibition, hydrochloric acid, Withania somnifera extract

Int. J. Corros. Scale Inhib., 2025, 14, no. 2, 793-822
doi: 10.17675/2305-6894-2025-14-2-19

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