Synthesis, characterization and evaluation of some graphene oxide derivatives and their application as corrosion inhibitors for carbon steel alloy type c1025 in hydrochloric acid

Abstract

In this work, graphene oxide was modified first by a reaction with sulfanilic acid and second, by a reaction with sulfamic acid. The prepared compounds were characterized by XRD, Raman shift, FESEM and EDS techniques. GO functionalized sulfanilic acid (GOC) and GO functionalized sulfamic acid (GOD) were evaluated as anticorrosion inhibitors for carbon steel alloy (C1025) in acidic 0.1 M HCl environment at 298 K by the electrochemical method (Tafel plot method). The data reveals that the efficiencies of GO, GOC and GOD are 77.4%, 90.2% and 92% respectively at optimal concentrations of 100, 50 and 70 ppm, respectively. The effect of temperature on the corrosion reaction was studied and the results show that increasing the temperature in the range of 298, 308, 318 and 328 K decreased the efficiency. Furthermore, the thermodynamic and kinetic parameters such as the activation energy (Ea), enthalpy of activation (∆H*), Gibbs free energy of activation (∆G*) and entropy of activation (∆S*) were studied. The results indicate that the prepared inhibitors obey the Langmuir adsorption isotherm with R2 near unity. The equilibrium constant Kads, Gibbs free energy of 0 0 0 adsorption (∆Gads), enthalpy of adsorption (∆Hads) and entropy of adsorption (∆ Sads) were.