Extensive theoretical study of corrosion inhibition efficiency of some pyrimidine derivatives on iron and the proposal of new inhibitor

Investigation of the anticorrosion and adsorption properties of two polymer compounds on the corrosion of SABIC iron in 1 M HCl solution by practical and computational approaches

The anticorrosion efficiency of two polymer compounds, namely polystyrene (PS), polybutylene terephthalate (PBT), against the corrosion of SABIC iron (S-Fe) in 1.0 M HCl solution was investigated. The anticorrosion efficiency was estimated by chemical and electrochemical measurements. The anticorrosion efficiency increased with the increase in the concentration of the polymer compounds and reduction in temperature. All the obtained corrosion data confirmed the anticorrosion strength in the presence of PS and PBT compounds, such as the decreasing values of the corrosion current density, capacity of the double layer, and weight reduction, while the values of the charge-transfer resistance increased. Also, the pitting potential values moved in the noble (+) direction. The anticorrosion efficiency of the PBT compound was higher than that of the PS compound, which was 95.98% at 500 ppm concentration for PBT while for PS it was 93.34% according to polarization measurements. The anticorrosion activity occurred by the adsorption of PS and PBT compounds on the surface of S-Fe according to the Langmuir isotherm. The polarization curves indicated that the PS and PBT compounds were mixed-type inhibitors. Density functional theory (DFT) and Monte Carlo simulation (MC) were performed for the two polymer compounds. The computational quantum functions were found to be in agreement with the experimental results.

Effective corrosion inhibition of mild steel by eco-friendly thiourea functionalized glucosamine derivatives in acidic solution

In the view of environmental protection and sustainable development, the application of green effective inhibitors for metal corrosion in industry field is of great significance. In this work, two thiourea functionalized glucosamine derivatives, 5-hydroxy-1-phenyl-4-(1,2,3,4-tetrahydroxybutyl)imidazolidine-2-thione (GA-1) and 1-phenyl-3-(2,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-3-yl)thiourea (GA-2), were synthesized as eco-friendly corrosion inhibitors for mild steel (MS) in 1 M HCl solution, and their inhibition performance were evaluated by electrochemical tests and surface analyses. The electrochemical tests and surface analyses indicate that both GA-1 and GA-2 have high inhibition performance. Especially for GA-2, the inhibition efficiency reaches 97.7% with a concentration of 0.64 mM. Theoretical calculations were also conducted to elucidate the adsorption mechanism of GA-1 and GA-2 on MS surface.