THERMAL EFFECTS AND ADSORPTION BEHAVIOR OF A FEW GREEN AND SYNTHETIC INHIBITORS ON API5LX60 STEEL IN CO₂-SATURATED SALINE MEDIA

The transportation of crude oil and natural gas employs steel pipes as an economic engineering material. However, despite its mechanical strength, it undergoes corrosion under drastic environmental conditions. In this line, temperature plays a pivotal role in the electrochemical processes of steel, whenever it encounters a corrosive medium, which is very often devastating. This paper, thus, reports the temperature effect at 298K, 303K, 313K, 323K and 333K on corrosion rates of three oxazolone derivatives, three plant extracts and blends of oxazolone derivatives with two plant extracts coated API5LX60 steel in 3.5% NaCl solution with CO2 saturation using gravimetric analysis data. The results revealed that increased temperature elevated the corrosion rate and depleted the % inhibition efficiency considerably. This outcome is consistent for all corrosion inhibitors examined, regardless of the inhibitor concentration. Three different adsorption isotherms obeyed by the reported inhibitors have also been considered with data from gravimetric analysis. The mode of adsorption was affirmed as physisorption, with the best fit given by the Langmuir adsorption isotherm, with the linear regression coefficient (R2 ) value approx. to one. This work thus has a significant contribution to both academic researchers and industrial corrosion engineers as it will serve as a valuable reference against thermal and adsorption modelling in the CO2 environment of synergistic synthetic and green corrosion inhibitors.