Polyoxyethylene sorbitan trioleate surfactant as an effective corrosion inhibitor for carbon steel protection

Corrosion of metals is a significant economic problem globally. The use of corrosion inhibitors, particularly those based on surfactants, is one of the most effective ways of protecting metal surfaces against corrosion. This study addresses the synthesis of a non-ionic oligomeric surfactant and its application as a corrosion inhibitor. The synthesis is a simple and scalable for accomplishing under mild conditions by catalytic esterification of maleic anhydride with polyoxyethylene sorbitan, and further modification of the ether with diethanolamine. The ability of inhibitor to protect a steel sample was evaluated in a solution that simulates compositions of formation waters, and found to be quite effective. The inhibitory behavior of non-ionic polyoxyethylene sorbitan trioleate surfactant (MA/TWEEN-DEA) on ST3 steel corrosion was examined using weight loss and SEM techniques. The compound inhibited the corrosion of carbon steel in a model solution simulating compositions of formation waters, and the extent of inhibition was dependent on temperature and concentration of compound. MA/TWEEN-DEA at 200 ppm exhibits an inhibition efficiency of 80% at 30 degrees C and 62% at 70 degrees C. Thermodynamic and kinetic parameters for ST3 steel corrosion and inhibitor adsorption were determined and discussed. The quantum chemical parameters were used to study the reactivity and adsorption behavior of surfactant. The results of experimental studies and the theoretical investigation well complimented each other.