European Journal of Biomedical and Pharmaceutical Sciences

POTENTIAL OF KEPOK BANANA CORM EXTRACT (MUSA PARADISIACA L.) AS A NATURAL CORROSION INHIBITOR ON ST-37 STEEL IN 3.5% NACL SOLUTION AND WATER MEDIA

Novia Permata Sari*, Anak Agung Bawa Putra, Manuntun Manurung, Ni Komang Ariati, I. Gusti Agung Gede Bawa, Dan I. Wayan Sudiarta

ABSTRACT

Corrosion is a form of damage to metals caused by electrochemical reactions between the material and its environment, resulting in a decline in the metal’s quality. One method that can be used to reduce the corrosion rate of metals is the use of inhibitors. This study aims to determine the corrosion rate and inhibition efficiency of St-37 steel in a 3.5% NaCl corrosive medium and water with the addition of an ethanol extract of kepok banana (Musa Paradisiaca L.) stems. Extraction was performed using the maceration method, and the corrosion rate was calculated using the weight loss method. Based on the weight loss test results, it was shown that the banana stem extract affects the corrosion rate, with the lowest corrosion rates observed at an optimal concentration of 10% in 3.5% NaCl solution and water, respectively 0.0206 and 0.0340 mm/year, with inhibition efficiencies of 90.1994% and 77.4199%, respectively. SEM-EDX results also indicate that the surface of St-37 steel without the addition of a banana stem extract inhibitor exhibits more uniform degradation and pitting across the entire surface, whereas the surface of St-37 steel treated with a 10% banana stem extract inhibitor has a smoother surface and fewer pitting locations. Additionally, there was an increase in Fe content and a decrease in O content in the steel treated with the 10% inhibitor, proving that the ethanol extract of kepok banana stems is capable of forming a protective layer to prevent corrosion on the surface of St-37 steel.

Keywords: St-37 steel, kepok banana stems, variation of inhibitor concentration, variation of corrosive media, corrosion rate.