Corrosion inhibition, hydrogen evolution and antibacterial properties of newly synthesized organic inhibitors on 316L stainless steel alloy in acid medium

Electrochemical corrosion behavior and hydrogen evolution reaction of 316L stainless steel has been investigated, in 0.5 M sulfuric acid solution containing four novel organic inhibitors as derivatives from one family, using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements and surface examination via scanning electron microscope (SEM) technique. The effect of corrosion inhibitors on the hydrogen evolution reaction was related to the chemical composition, concentration and structure of the inhibitor. The inhibition efficiency, for active centers of the four used compounds, was found to increase in the order: -Cl < -Br < -CH₃ < -OCH₃. The corrosion rate and hydrogen evolution using the compound with methoxy group as a novel compound was found to increase with either increasing temperature or decreasing its concentration as observed by polarization technique and confirmed by EIS measurements. The compound with methoxy group (newly synthesized) has very good inhibition efficiency (IE) in 0.5 M sulfuric acid (98.3% for 1.0 mM concentration). EIS results were confirmed by surface examination. Also, antibacterial activity of these organic inhibitors was studied. The results showed that the highest inhibition efficiency was observed for the compound that posses the highest antibacterial activity.