engleski

Natural deep eutectic solvents as corrosion inhibitors in high acidic media

Corrosion of metals and their alloys has a major impact not only on the economy but also on the environment. Corrosion of these materials is especially pronounced in very acidic solutions such as hydrochloric acid [1, 2]. HCl is extensively used in a number of chemical and industrial processes such as acid pickling, acid cleaning, acid descaling and oil-wet cleaning of steel and ferrous alloys [3]. One of the best and most widely used methods for increasing the rate of metallic corrosion is addition of inhibitors in acid solution [4]. Natural deep eutectic solvents (NADES) as a new type of green solvents have some promising features for corrosion inhibitors such as: low cost and easy preparation, high thermal stability and low toxicity [5, 6]. The purpose of this study was to investigate the eight NADESs as corrosion inhibitors of the stainless steel (X6CrNiTi18-10) which is extensively used in chemical and food industry. It is well known, that the effect of temperature on the inhibition of metal in acid is highly complex, due to the many changes that take place on the metal surface, such as desorption of the inhibitor, and due to the fact that the inhibitor itself may undergo decomposition ; gravimetric measurements were done in a temperature range from 25°C-85°C in 1 M HCl solution. Since, the all investigated NADES showed very high inhibition efficiencies (80-99%), which is not drastically changed at high temperatures, some thermodynamic and kinetic parameters were also calculated. Moreover, to confirming these results, metallographic microscopy of steel surface was done.

NADES; corrosion; inhibitors; steel

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