Pengaruh Lignin Hasil Ekstraksi dari Tandan Kosong Kelapa Sawit (TKKS) sebagai Green Inhibitor Korosi terhadap Baja ST 41 dalam Media Asam Sulfat

Abstract

This research was conducted to investigate the effect of inhibitor concentration and immersion time on weight loss, corrosion rate, inhibition efficiency, and surface roughness variation of low-carbon steel ST 41. The study also aimed to evaluate the inhibition efficiency of lignin extracted from Oil Palm Empty Fruit Bunches (EFB) in reducing the corrosion rate of ST 41 steel and to analyze the morphological characteristics of the steel surface both with and without the inhibitor. The weight loss method was employed as the primary technique, as it is the simplest approach to determine the corrosion rate by comparing the initial weight of the specimen to its weight after immersion in the inhibitor solution. Morphological characterization and identification of the corrosion type were carried out through microscopic and cross-sectional observations. The results showed corrosion rate values of 31.6922 mpy, 24.8851 mpy, and 19.7146 mpy, corresponding to inhibition efficiencies of 34.56%, 53.93%, and 79.305% for the 3 g/L inhibitor concentration at immersion times of 1 hour, 3 hours, and 6 hours, respectively. Meanwhile, at a concentration of 7 g/L, the corrosion rates were 26.3358 mpy, 20.3842 mpy, and 15.9577 mpy, with inhibition efficiencies of 45.62%, 62.26%, and 83.24% for the same immersion durations. The adsorption behavior of the inhibitor on ST 41 steel was evaluated using the Langmuir adsorption isotherm model, which indicated that the dominant adsorption mechanism was physisorption.