INVESTIGATION OF INHIBITORY EFFECT OF THE RASPBERRY FRUIT EXTRACT (Rubus idaeus L.) ON CORROSION OF COPPER IN 3% NaCl SOLUTION

Abstract

The paper presents an examination of the possibility of applying raspberry fruit extract (Rubus idaeus L.) as a green inhibitor of general corrosion of copper in 3% NaCl. Raspberry fruits (Rubus idaeus L.) sort Polka was collected from the Starposle near Kakanj, Bosnia and Herzegovina. Raspberry fruit extracts in ethanol were obtained by the Soxhlet extraction and the ultrasonic method. By UV/VIS spectrophotometry analysis, a significant content of polyphenols was found in the raspberry fruit extracts. Due to the great importance of gallic acid, the concentration of gallic acid was also determined using liquid chromatography. Corrosion testing of copper by the DC techniques was performed on a measuring device consisting of an electrochemical cell and a potentiostat/galvanostat, and electrochemical impedance spectroscopy measurements were performed using a potentiostat/galvanostat. Results obtained by the DC technique (by the method of Tafel extrapolation) prove that the corrosion rate decreases in the presence of the raspberry fruit extract. Tests performed by the method of electrochemical impedance spectroscopy prove that the tested extracts slow down the kinetics of the corrosion process, which is visible through the increase in resistance. The results of the conducted tests prove that in an aggressive medium, such as a 3% NaCl solution, Polka raspberry fruit extract can be used as an inhibitor of copper’s corrosion.

Keywords

• raspberry fruit
• Tafel extrapolation
• electrochemical impedance spectroscopy