Rosemary Plant Dye Extract as an Anti-Corrosion Supplement for Mild Steel in Acid Solution: Experimental and Statistical Approach

This study investigates the corrosion inhibition potential of rosemary (Rosmarinus officinalis) plant extract as a green alternative to synthetic inhibitors. The study employed experimental (weight loss) and statistical (response surface methodology (RSM)) technique evaluate the inhibition performance of the Rosemary dye plant extract (RDPE). Fourier transform infra ray spectroscopy (FTIR) of the pure and corrosion products were carried out to determine the functional groups of the pure and corroded sample of the plant extract. The phytochemical analysis shows some biotic constituents of the RDPE such as Alkaliods (mg/100g), cardiac glycosides (mg/100g), Flavonoids (mh/100g), phenolic (GAE/g). which are the chemical constituents of the plant extract that inhibited the metal from corrosion. In the same vein, the adsorption isotherms were evaluated and used to evaluate thermodynamic parameters to determine the adsorption mechanism, of the dissolution process. The results obtained shows that the highest inhibition efficiency value is 94.07 % for the weight loss and 94.76 % for the RSM techniques. The FTIR results showed that RDPE molecules was adsorbed onto the mild steel surface. Kinetic study shows that the RDPE molecules obeyed the Frumkin isotherm and was used to determine the adsorption mechanism which is of physiosorption procedure. Rosemary extract effectively inhibits mild steel corrosion, offering an eco-friendly, biodegradable, and cost-effective alternative to synthetic inhibitors. Future research should focus on large-scale industrial applications, long-term stability, and optimization of extraction methods for improved efficiency.