Anticorrosive efficiency and adsorption characteristics of natural plant gums on mild steel exposed to the Diesel/Saline water biphasic system

Metallic equipment and structures that come in contact with a variety of petroleum products, solvents, water, the atmosphere, and soil in the oil and gas industry are highly prone to a range of corrosion phenomena, which escalate the risk of serious accidents. The use of green corrosion inhibitors in oil and gas can significantly reduce the maintenance and service costs. This study focuses on the anti-corrosive behavior of natural exudate gums, such as Azadirachta indica (G1), Moringa oleifera (G2), Prosopis juliflora (G3) and Prunus dulcis (G4). These gums were evaluated as corrosion inhibitors on mild steel against the diesel/saline water biphasic system by the weight loss method and electrochemical techniques. The inhibition efficiency was high at 93.86, 95.75, 92.42, and 90.02% at the highest tested concentration (5,000 ppm) for the gums G1, G2, G3, and G4, respectively. Among the investigated natural gums, the lowest corrosion rate (29.36 mm yr −1 ) and highest inhibition efficiency (95.75%) were achieved with Moringa oleifera (G2) at 5,000 ppm. The activation energy of the corrosion inhibition process (4.00–38 kJmol −1 ) was higher than that of the uninhibited system (1.8 kJmol −1 ), indicating that the inhibited systems possessed higher energy barriers and followed the Langmuir adsorption process. Our corrosion test results validate that the Moringa oleifera gum can serve as an effective eco-friendly corrosion inhibitor for mild steel in the biphasic system of diesel/saline water.