Corrosion mitigation characteristics of some novel organoselenium thiourea derivatives for acid pickling of C1018 steel via experimental and theoretical study

by Selleckchem | Aug 28 2023

Two organoselenium thiourea derivatives, 1-(4-(methylselanyl)phenyl)-3-phenylthiourea (DS036) and 1-(4-(benzylselanyl)phenyl)-3-phenylthiourea (DS038) were produced and categorized using FTIR and NMR (1H and 13C). The effectiveness of the above two compounds as C-steel corrosion inhibitors in molar HCl was evaluated using the potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS) techniques. PD findings indicate that DS036 and DS038 have mixed-type features. EIS results show that growing their dose not only changes the polarization resistance of C-steel from 18.53 to 363.64 and 463.15 Ω cm2 but also alters the double layer capacitance from 710.9 to 49.7 and 20.5 μF cm-2 in the occurrence of 1.0 mM of DS036 and DS038, respectively. At a 1.0 mM dose, the organoselenium thiourea derivatives displayed the highest inhibition efficiency of 96.65% and 98.54%. The inhibitory molecule adsorption proceeded along the Langmuir isotherm on the steel substrate. The adsorption-free energy of the adsorption process was also intended and indicated a combined chemical and physical adsorption on the C-steel interface. FE-SEM studies support the adsorption and protective abilities of the OSe-based molecule inhibitor systems. In Silico calculations (DFT and MC simulations) explored the attraction between the studied organoselenium thiourea derivatives and corrosive solution anions on a Fe (110) surface. The obtained results show that these compounds can make a suitable preventing surface and control the corrosion rate.

Comments:

The given paragraph provides information about the synthesis and characterization of two organoselenium thiourea derivatives, namely DS036 and DS038. The compounds were evaluated for their effectiveness as corrosion inhibitors for C-steel in molar HCl using potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS) techniques.

The potentiodynamic polarization (PD) findings indicate that both DS036 and DS038 exhibit mixed-type features as corrosion inhibitors. This means that they can inhibit both the anodic and cathodic processes involved in the corrosion of C-steel.

The electrochemical impedance spectroscopy (EIS) results show that increasing the concentration of DS036 and DS038 not only changes the polarization resistance of C-steel but also alters the double layer capacitance. Specifically, the polarization resistance increases from 18.53 to 363.64 and 463.15 Ω cm2, and the double layer capacitance decreases from 710.9 to 49.7 and 20.5 μF cm-2 in the presence of 1.0 mM of DS036 and DS038, respectively. These changes indicate that the corrosion rate of C-steel decreases significantly in the presence of the organoselenium thiourea derivatives.

At a concentration of 1.0 mM, both DS036 and DS038 exhibited high inhibition efficiencies of 96.65% and 98.54%, respectively. This means that they were very effective at preventing corrosion of C-steel in molar HCl.

The inhibitory molecule adsorption on the steel substrate followed the Langmuir isotherm, indicating that the adsorption process was monolayer formation. The adsorption-free energy of the adsorption process was calculated, suggesting that the adsorption mechanism involved a combination of chemical and physical interactions at the C-steel interface.

FE-SEM studies (Field Emission Scanning Electron Microscopy) supported the adsorption and protective abilities of the organoselenium thiourea derivatives as corrosion inhibitors. This suggests that the compounds formed a protective layer on the surface of C-steel, preventing further corrosion.

In addition to experimental studies, in silico calculations were performed using density functional theory (DFT) and Monte Carlo (MC) simulations. These calculations explored the interactions between the organoselenium thiourea derivatives and corrosive solution anions on a Fe (110) surface. The results indicated that these compounds can form suitable protective surfaces and effectively control the corrosion rate of C-steel.

Overall, the paragraph highlights the synthesis, characterization, and evaluation of DS036 and DS038 as corrosion inhibitors for C-steel in molar HCl. The compounds showed promising inhibitory properties through experimental techniques, and in silico calculations supported their potential as effective corrosion inhibitors.