Corrosion Inhibition, Adsorption and Thermodynamic Properties of Poly (Sodium 4-Styrenesulfonate) on Carbon Steel in Phosphoric Acid Medium

The use of polymers as corrosion inhibitors has attracted much attention due to their low prices, inherent stability, availability and cost-effectiveness. The corrosion inhibiting effect of poly(sodium-4-styrenesulfonate) on carbon steel in phosphoric acid solution has been investigated using weight loss and scanning electron microscopy techniques (SEM) and theoretical calculations based on density functional theory (DFT). In the presence of 1.0×10-3 mol/L of inhibitor, a maximum inhibition effect of 98.06 % was observed. The influence of the concentration of the inhibitor, the temperature of the solution and the immersion time on the corrosion of carbon steel was investigated. Activation parameters such as activation energy (Eact), activation enthalpy (ΔHact), activation entropy (ΔSact), heat of adsorption (Qads) and adsorption free energy (ΔGads) were evaluated based on the effect of temperature on the corrosion and inhibition processes. It was found that the adsorption behaviour of poly(sodium-4-styrenesulfonate) (PSS) follows the Langmuir isotherm and the free energy change values indicate mixed chemical and physical adsorption on the carbon steel surface. The results obtained with the different methods agree well

Enhancing Corrosion Resistance of Carbon Steel in Sulfuric Acid Using β-cyclodextrin as an Inhibitor

The corrosion process leads to substantial economic losses, particularly in the industrial sector, emphasizing the importance of preventive measures. This study aimed to investigate the impact of inhibitor concentration, immersion duration, and temperature on the corrosion of carbon steel in a sulfuric acid environment, assessed through mass loss measurements. Inhibition efficiency displayed a positive correlation with increasing inhibitor concentration, while it declined as temperatures rose. In a 0.5 M sulfuric acid solution, β-cyclodextrin (β-CD) exhibited an inhibition efficiency of 62.26% at a concentration of 1 mM. The addition of potassium iodide (KI) significantly enhanced the inhibition efficiency to 97.98%, indicating a synergistic effect. The study encompassed various calculations, including the determination of activation energy (Ea), activation enthalpy (ΔHa), activation entropy (ΔSa), adsorption-free energy (ΔGads), adsorption enthalpy (ΔHads), and adsorption entropy (ΔSads). The adsorption of the inhibitor onto the carbon steel surface conformed to the Langmuir adsorption isotherm. Additionally, Scanning Electron Microscopy (SEM) investigations provided further verification of β-cyclodextrin's adsorption on the carbon steel surface

Polyvinylpyrrolidone as a Corrosion Inhibitor for Carbon Steel in a Perchloric Acid Solution: Effect of Structural Size

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

Experimental and Theoretical Studies of Eosin Y Dye as Corrosion Inhibitors for Carbon Steel in Perchloric Acid Solution

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 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Application of polyvinylpyrrolidone-iodine complex as corrosion inhibitor for carbon steel using an experimental design method

Corrosion processes are responsible for numerous losses, especially in the industrial sector. Inhibitors are commonly used to prevent corrosion in acidic medium. The aim of this study was to apply an experimental design to optimize the influencing parameters such as inhibitor concentration, temperature and immersion time on the corrosion inhibition of polyvinylpyrrolidone-iodine (PVP-I) complexes on carbon steel using the weight loss technique (WL). The parameters of the corrosion protection process were optimized and predictive mathematical models were developed using the Response Surface Methodology (RSM) using the Central Composite Design (CCD). It was also found that the data predicted by the regression analysis had a good agreement with the data obtained from the experiments, with the values R2 = 0.999 and Adj. R2 = 0.997 for the inhibitory effect. The best efficiencies for experiments that were not performed were determined by experimental design (DOE