Feasibility study of water hyacinth (Eichhornia crassipes) leaf extract as an environmentally friendly corrosion inhibitor in the NaCl, acetic acid, and CO₂ environment

Water hyacinth is a type of water weed that often cause problems. Its presence in large numbers in reservoirs may reduce the performance of hydroelectric power plants (PLTA) and can cause blockages in irrigation channels. Based upon several publications, water hyacinth leaves show good performance as corrosion inhibitor in the NaCl and hydrochloric acid environment. In this research the electrochemical method was used to investigate the feasibility of water hyacinth leaf extract as corrosion inhibitor for API 5L X-65 steel in NaCl, acetic acid, and CO₂ environment. Furthermore, the addition of water hyacinth leaf extract concentrations with the most optimal efficiency was evaluated by the immersion method for 24, 72, and 120 hours. Evaluations of the specimen surface was also carried out using SEM. The effectiveness of the inhibition increases with the increasing of the extract concentration. The polarization test results indicate that water hyacinth leaf extract is classified as a mixed type inhibitor. The values of the capacitance and resistance parameters show an increase I the thickness of the double layer as the concentration increases. The effect of water hyacinth leaf extract inhibition as corrosion inhibitor can be seen from the phenomenon of water hyacinth leaf extract adsorption on the steel surface which can be approximated by using Langmuir isothermal adsorption model. The results of immersion testing show a decrease in the ability of water hyacinth leaf extract inhibition as the function of time. The SEM characterization results in a decrease of surface roughness of the specimen with the addition of water hyacinth leaf extract.