Corrosion Inhibition Effect Of Sugarcane Bagasse Extract On N80 Steel In CO 2 Environment

In this article, heating magnetic stirring method and soxhlet extraction are used to obtain two inhibitors respectively, they are saccharum sinense bagasse extract (SSBE)(hereinafter referred to as bagasse extract) and endives extract (EE). Fourier transform infrared spectroscopy (FTIR) is used to characterize the functional groups of the extracts. According to the results, the two extracts both contain O-H, N-H, C=O, C-O and C-N polar groups, they both have the potential to be corrosion inhibitors.Electrochemical impedance spectroscopy (EIS) and polarization-curve method are used to evaluate the inhibition effect of the SSBE and EE to N80steel in CO2-saturated3.5wt.%NaCl solution at the room temperature. The results reveal that, when the concentration of SSBE is8%v/v (volume ratio), the inhibition efficiency is up to90.2%(EIS) and91.6%(Tafel) respectively, and when the concentration of EE is16%v/v, the inhibition efficiency is81.3%(EIS) and81.3%(Tafel) respectively. For its better inhibition efficiency and less usage amount, SSBE is chosen for subsequent research. The adsorption characteristics of the two extracts both obey the Langmuir adsorption isotherm, and the dynamic models both conform to El-Awady dynamics model. The adsorption processeses are both spontaneous, and the adsorption films are both single molecule adsorption films.Scanning Electrochemical Microscope (SECM) is used to test the substrate surface current of N80steel in the presence and absence of SSBE, to characterize the film forming condition of inhibitor molecules. The results show that the surface current of N80steel decreases after adding SSBE, surface morphology becomes more smooth, it illustrates that inhibitor molecules have formed a protective film on the surface.Contact angel measurement (CA) has been used to test the contact angle between N80steel and corrosion solution with different concentration of SSBE. The results show that, with the concentration of SSBE increasing, the contact angle increases, it reveals that the addition of inhibitor reduces the hydrophilicity of the corrosion solution, thereby reduces the corrosive substances contact with N80steel in the solution, thus reduces the occurrence of corrosion.Weight loss (WL) and electrochemical methods are used to study the effect of experimental temperature and time on SSBE’s inhibition efficiency. Results show that the inhibition efficiency decreases when the experimental temperature and time are increasing It reveals that its inhibition efficiency is obviously affected by the temperature and time.