engleski

Corrosion Inhibition of Carbon Steel in 0.5 M HCl by 12-Aminododecanoic Acid as an Environmentally-Friendly Corrosion Inhibitor

Corrosion of metallic materials represents one of themajor problems that faces the oil and gas industry. Although carbon steel is widely emplyed as a construction material for pipe work in oil and gas production, its corrosion resistance is very low. The most common way of mitigating this problem is by using corrosion inhibitors. However, many common corrosion inhibitors that are in use today are health hazards. In this work we have studied the inhibiting effect of a "green" molecule, 12-aminododecanoic acid, (AA), on the corrosion of carbon steel (CS) in 0.5 M HCl, in a wide temperature and pH range. It was found that AA acts as a good CS corrosion inhibitor, yielding a maximum corrosion inhibition efficiency of 92% at pH 2.5. This high inhibition efficiency is maintained even at higher temperatures. Kinetic measurements demonstrated that inhibition efficiency of ca. 81% is achieved within thirty minutes after application of the inhibitor, while the maximum efficiency is achived after one hour. It was determined that AA acts as a mixed-type inhibitor. In-situ polarization-modulation infrared reflection absorption spectroscopy measurements revealed that AA forms a medium-ordered self-assembled monolayer on the steel surface. This process is spontaneous and reversible ; the gibbs energy of adsorption was found to be -12 kJ mol^(-1). Scanning electron microscopy also demonstrated that the AA is a very effective general corrosion inhibitor of CS at low pH values.

Carbon steel; 12-aminododecanoic acid; self-assembled monolayers; corrosion

nije evidentirano