This study examined the potential of Isapa leaf extract (ILE) as a corrosion inhibitor of carbon steel API 5LX70 in gas industries using a 1–3% H₂SO₄-HCl-HNO₃ blend solution. The Isapa leaf was extracted using an organic solvent (acetone). The phytochemical and physicochemical properties of the extract were investigated. The corroded carbon steel API 5LX70 elemental composition was ascertained using X-ray Fluorescence (XRF). The acidic blend solution was obtained using the combined simplex lattice design and I-optimal design. The weight loss method was used to determine the adsorption studies, corrosion rate, and inhibition efficiency. The fitness of the absorption isothermal study was evaluated using different isotherms, and the thermodynamic parameters were evaluated using the corrosion rate and transitional state equations. Process modeling and optimization were carried out using RSM-SSCRD, ANN-GA, and ML-Python base.Results showed ILE had a pH of 2.64, indicating a slight acidity, and a low moisture content of 0.001%. Flavonoids were discovered to be prevalent as secondary metabolites. The carbon steel API 5LX70 had a highly corroded iron content of 89.677 wt%. The acid blends that were validated using simplex lattice incorporated I-optimal design were 1.10, 1.42, and 1.72 g/L. Carbon steel API 5LX70's weight loss and corrosion rate increase with temperature and immersion time but decrease with extract concentration. The positive values of ΔH showed that ILE was adsorbed on the carbon surface. The Langmuir isotherm adsorption proved to be fitted for the adsorption. Process optimization showed that the ML-Python base performed better than the RSM-CCRD and ANN-GA in terms of validated optimum IE of 96.20% and minimum CR of 2.46 (mm/yr) at immersion time of 5 h, temperature of 350 K, and inhibition concentration of 1.62 g/L. The study concluded that using ILE in the presence of a blended acid solution effectively controlled the corrosion of API 5LX70 carbon steel. • Isapa leaf extract (ILE) was used as a corrosion inhibitor. • Corroded carbon steel API: 5LX70 was used as a case study. • The weight loss and corrosion rate of carbon steel API: 5LX70 increase. • Isotherm testing revealed that the Langmuir isotherm is observed. • Validated optimum IE and minimum CR were obtained using ML-python base.
Essien et al. (Fri,) studied this question.