Insight into anti-corrosion behavior of protein extract as eco–friendly corrosion inhibitor

In this study, corrosion inhibitors from waste protein were extracted, and their anti–corrosion behavior was investigated on a laboratory–scale. The functional groups of the protein waste extract (PWE) were identified using Fourier transform infrared (FTIR) spectroscopy. High–performance liquid chromatography (HPLC) was used to determine the variety and concentration of the amino acids. The efficiency of the inhibitor was assessed by electrochemical experiments. The results show that PWE, as an environmentally friendly corrosion inhibitor, has the highest corrosion inhibition efficiency of up to 96.2% at a temperature of 298 K and a concentration of 1000 ppm. The mechanism of PWE was evaluated by atomic force microscopy (AFM) and X–ray photoelectron spectrometry (XPS). The findings demonstrated that the PWE contains 17 different types of amino acids that can effectively adsorb onto the metal and inhibit the corrosion reaction of steel in an acidic environment. The polarization curve confirmed that the PWE was a mixed type of inhibitor. This work could provide useful insights into the development and utilization of eco–friendly corrosion inhibitors.