Green chemistry approach to corrosion prevention: Saccocalyx satureioides as an effective inhibitor for C45 steel in acidic medium (HCl)

Carbon steel's corrosion in harsh, acidic environments presents significant challenges to industrial use. While traditional inhibitors are effective, they often raise environmental and sustainability concerns. This study explores the potential of Saccocalyx satureioides extract (S. Satureioides) as an environmentally Eco-friendly corrosion inhibitor for protecting carbon steel 45 in a highly corrosive 0.5 M HCl solution. The organic components of the sample were identified using phytochemical screening, LC-MS analysis, and ATR-FTIR spectroscopy. The main compounds detected were coumaric acid (68.10%), 4-methoxybenzoic acid (15.15%), and kaempferol (11.36%). Weight loss measurements demonstrated that the S. Satureioides extract had a highly effective anti-corrosion capability, achieving an inhibitory efficiency of around 96.93% at a concentration of 3 g.L-1 at a temperature of 25°C after 360 hours of immersion. This significantly reduced the corrosion rate from 0.1721 mg.cm−2.h−1 to 0.0053 mg.cm−2.h−1. The adsorption isotherms indicated that the adsorption of S. Satureioides molecules onto the steel surface followed the Langmuir model, exhibiting a high correlation coefficient of 0.9958. The negative value of the adsorption free energy ( = -17.162 kJ mol-1) indicates that the physisorption interactions occurred spontaneously. The SEM/EDX analysis revealed that the steel surface exhibited reduced damage due to the inhibitor's protective coating formation. This research not only significantly contributes to corrosion science filed but also provides crucial support for global efforts to promote sustainable industrial practices, with potential applications in various industries worldwide.