Upcycling sorghum lees residue into high-performance green corrosion inhibitors: An integrated computational and experimental study

To promote the diversified utilization of sorghum lees and contribute to environmental sustainability, an eco-friendly corrosion inhibitor was prepared from sorghum lees extract (SLE). The main constituents of SLE were characterized via liquid chromatography-mass spectrometry (LC-MS) and Fourier transform infrared spectroscopy (FTIR). Quantum chemical calculations and molecular dynamics simulations were performed to predict the adsorption behavior of its active components onto an Fe atomic layer under acidic conditions, revealing that molecules abundant in heteroatoms (N and O) act as the predominant adsorption sites. Moreover, X-Ray Photo Electron Spectrometry (XPS) has confirmed the presence of the absorption layer, and Focused Ion-Beam Transmission Electron Microscope (FIB-TEM) has shown that the modification layer has been formed. Furthermore, a further assessment by electrochemistry and static mass loss experiments showed that SLE was able to inhibit CRS in 1.0 M HCl. The results showed that the SLE added significantly improved the resistance to charge transfer, decreased the double layer capacity, and provided excellent inhibitory properties. At 30°C, the rate of absorption is 93.08%, and the absorption is in accordance with the Langmuir absorption isotherm. In addition, SLE markedly prolonged the half-life ( t 1/2 ) of the system. These results demonstrate that SLE has the potential to be an environmentally friendly material, with the potential for continuous corrosion protection.