COMPARATIVE STUDY OF EXTRACTION METHOD OF RAMBUTAN PEEL BY MACERATION AND ULTRASONIC TECHNIQUE FOR STEEL CORROSION INHIBITOR ON HYDROCHLORIC ACID SOLUTION

• Main Author: Steven Siagian, Yohan
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/84848
• Institution: Institut Teknologi Bandung

biochemical, and electrochemical interactions between metals and alloys and the environment. Corrosion can occur on all metals and alloys, including steel. Corrosion that occurs in steel cannot be stopped but can be controlled by several methods, one of which is the addition of inhibitors. In recent years, inhibitors that are being developed are environmentally friendly inhibitors or Green Corrosion Inhibitors (GCI), one of which comes from plants. Rambutan is one of the plants developed as a GCI because it contains tannin and flavonoid compounds that are proven to inhibit corrosion rates. This research was conducted to study the effect of rambutan peel extraction method, type of solvent, extraction time duration, and solid percent as a corrosion inhibitor on its inhibition efficiency on API 5L Grade X52M steel in 1 M HCl solution. The rambutan peel extract was prepared by two methods. The first method is maceration with solvent variation of ethanol, acetone, and distilled water, maceration duration of 18 hours, 24 hours, and 48 hours, and solid percentage variation of 10% and 5%. For the Ultrasonic-Assisted Extraction method, the temperature was 50? and the solid percent was 5% with a variation of extraction time of 20 minutes, 40 minutes, and 60 minutes. Immersion tests were conducted for 24 hours at 25? to determine the corrosion rate and efficiency of each inhibitor tested. Electrochemical tests carried out included open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) tests. Surface characterization tests consisting of optical microscope (OM) and scanning electron microscope (SEM) and organic compound characterization using fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-Vis) were then conducted. The results of the immersion test showed that different methods, type of solvent, duration of extraction time, and solid percentage in rambutan peel extraction can affect the inhibition efficiency. From the immersion test results, the highest inhibitor efficiency was 92.57%, achieved with rambutan extracted by maceration method for 18 hours with 5% solid. The electrochemical test showed that the inhibitor was a mixed type inhibitor with an equivalent electrical circuit model Rs- L-(CPEi(Ri(CPEdl/Rp))). In the surface characterization test, it was known that the sample immersed in the blank solution has a rougher surface compared to the sample immersed in the solution containing the inhibitor. From the results of the corrosion product characterization test, it was concluded that there were organic compounds from rambutan peel extract absorbed on the steel surface.