Olive Leaf Extract as a Potential Anti-Corrosion of Copper-Nickel in Natural Seawater

Abstract

This study investigates the phenolic composition of olive leaves from Skikda region (Northern Algeria), focusing on their therapeutic potential for diabetes and hypertension due to their high content of phenols, particularly oleuropein. The leaves were dried, micronized and characterized by FT-IR spectroscopy. The obtained powder was subjected to various extraction techniques, including microwave, Soxhlet, Ultrasound-Assisted Extraction (USAE) and traditional maceration. The extracted compounds were analyzed by gas chromatography-mass spectrometry (GC/MS) and Ultra-High Performance Liquid Chromatography (UHPLC) coupled with electrospray ionization-quadrature-time-of-flight mass spectrometry (ESI-Q-TOF-MS). The presence of olivetol and two oleuropein isomers, highlighted the rich phenolic profile of the leaves. The study also examines the efficacy of olive leaf extract, particularly from traditional maceration, to prevent corrosion in the Cu-Ni alloy (90/10) seawater, one of the most corrosive environments. The results showed a high inhibitory efficiencies of 96.8% for the highest concentration (S1) by Tafel and 93% for the lower concentration (S3) by Electrochemical Impedence Spectroscopy (EIS). Scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analyses confirmed that the surface of the treated alloy remains free of corrosion, unlike the untreated alloy, which shows significant deterioration with a black corrosion layer attributed to the cuprite Cu2O. The study focuses on the identification of olivetol in olive leaf extract and its remarkable properties, for potential and preventive applications against corrosion