The adsorption behavior and the inhibition performance of Eosin Y Dye for carbon steel corrosion in 1 M perchloric acid solution have been carried using weight loss and scanning electron micrograph (SEM) techniques as well theoretical calculations based on density functional theory (DFT). The studied inhibitor concentrations were between 5´10-5 M and 5´10-3 M. Results obtained revealed that Eosin Y is an effective inhibitor and its inhibition efficiency increases with increasing concentration to attain 96.91% at 5´10-3 M at 30 °C. Thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy were obtained from experimental data of the temperature studies of the inhibition process at five temperatures ranging from 20 to 60 °C. It was found that the adsorption of Eosin Y could prevent steel from weight loss and the adsorption accorded with the Langmuir adsorption isotherm. The free energy of adsorption showed that the corrosion inhibition takes place by spontaneous physicochemical adsorption of inhibitor molecules on the carbon steel surface. SEM and DFT studies confirm the adsorption of Eosin Y on carbon steel surface. Copyright © 2020 BCREC Group. All rights reserved

No abstract

Polymers are materials composed of macromolecules characterized by duplicates of smaller molecules that are covalently bonded together to provide a set of properties. Corrosion inhibition by such compounds is usually attributed to their adsorption on the metal-solution interface. The inhibition effect of different sizes of polyvinylpyrrolidone (PVP) on the corrosion of carbon steel (C-steel) in solutions of perchloric acid was investigated. The inhibition efficiency increases as the size of the inhibitor and its concentration increases, but decreases as the temperature increases and can reach a value of 81.53% and 5.0x10^-3 mol L^-1(PVP: 58,000 g mol^-1) at 30°C. The most remarkable inhibition efficiency was confirmed by the presence of the film formed on the metal surface by scanning electron microscopy. The kinetic and thermodynamic parameters for the corrosion of C-steel and adsorption of the inhibitor were determined and discussed. The combination of PVP with potassium iodide produced a strong synergistic effect on the inhibition of C-steel corrosion leading to a significant improvement in the inhibition efficiency. Quantum chemical parameters were studied using density functional theory to determine the possible relationship between the inhibitor and its electronic properties.

Inhibition efficiencies (IE) process in polyvinylpyrrolidone (PVP) which is influenced by independent factors, concentration and size of PVP, temperature, time of immersion, and perchloric acid concentration was investigated in this paper. The relationship between factors and their responses is established by the concept of response surface methodology (RSM) explicitly through regression statistical analysis and probabilistic analysis is used in this work. The concept is a combination of mathematical and statistical techniques allowing the modeling and problems analysis by experimental design. In this study, the results based on statistical analysis showed that the quadratic models for the inhibition efficiencies (IE) were significant at the value of probability P < 0.0001 and the coefficient of multiple regressions R2=0.9997, for further validation of the model, R2Adj=0.9993 indicated a good model. The observed experimental values were in good agreement with predicted ones and the model washighly significant with Q2= 0.9884. The optimal conditions of inhibition efficiencies (IE) obtained are 104.301% for a concentration of 3.55×10−3 mol/L, temperature of 20.15°C, immersion time of 2h, size of PVP 58000 g/mol, and acid concentration of 0.5 mol/L.

The Neutral Red (NR) has been investigated as a corrosion inhibitor for carbon steel (C-steel) in 1M perchloric acid using a weight loss method and theoretical calculations based on density functional theory (DFT). The obtained results revealed that NR is an effective inhibitor and its inhibition efficiency increases with the increasing concentration to attain 89.50 % at 5•10-3 M at 293 K. The thermodynamic parameters as enthalpy, entropy and Gibbs free energy for both dissolution and adsorption processes are calculated and discussed. Moreover, the free energy of adsorption showed that the corrosion inhibition takes place by a spontaneous physicochemical adsorption of inhibitor molecules on the C-steel surface. The results show that the calculated values of the quantum chemical parameters indicate a possible existing link between the effectiveness of the inhibitor and its electronic properties.