INVESTIGATING THE CORROSION INHIBITION PROPERTIES OF ORANGE PEEL ON MILD STEEL IN ACIDIC ENVIRONMENT

ABSTRACT Corrosion of mild steel in acidic conditions remains a key concern in industrial systems such as acid cleaning, pickling, and oilfield activities. Conventional inhibitors, however effective, are generally harmful and non-biodegradable, leading to environmental and safety issues. Therefore, the use of eco-friendly inhibitors produced from natural sources has generated increasing attention. The aim of this research was to investigate the corrosion inhibition properties of orange (Citrus sinensis) peel on mild steel in 0.02 N H₂ SO₄ environments. The extract was made by soaking 80g of orange peel powder in 400 mL of ethanol (1:5 w/v ratio) for 72 hours, producing a yield of 24g of concentrated extract after solvent evaporation. The extract was diluted to obtain varied inhibitor concentrations of 0.05% w/v, 0.1% w/v, 0.15% w/v, and 0.2% w/v. The corrosion inhibition performance was assessed using the gravimetric (weight loss) method. The results proved that mild steel corrosion increased with the duration of exposure and decreased with increasing inhibitor concentration. The extract showed considerable inhibition efficiency, attributed to the adsorption of phytochemical elements on the steel surface, generating a protective coating that inhibited metal dissolution. The highest inhibition efficiency of 92.9% occurred at the highest extract concentration (0.2%) while the lowest inhibition efficiency of 74.3% was observed at the lowest extract concentration (0.05%). It was discovered that orange peel extract functions as an efficient and environmentally friendly inhibitor for mild steel corrosion in sulphuric acid solution. The study shows that natural waste products such as orange peels could serve as sustainable replacements to synthetic inhibitors. Future research is recommended to use advanced surface characterization techniques (e.g., SEM, FTIR) and test performance in various corrosive conditions to improve understanding of the inhibitory mechanism.