Performances of Alkaloid Extract from<i>Rauvolfia macrophylla</i>Stapf toward Corrosion Inhibition of C38 Steel in Acidic Media

Ngouné, Bertrand; Pengou, Martin; Nouteza, Armel Megha; Nanseu‐Njiki, Charles Péguy; Ngameni, Emmanuel

doi:10.1021/acsomega.9b01076

Cited by 42 publications

(29 citation statements)

References 45 publications

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“…Inhibition efficiency (IE %) is estimated by the eq 19(58)where R ct (Ω cm 2 ) and R ct(inh) (Ω cm 2 ) are the charge transfer resistances in the absence and presence of the inhibitor, respectively.…”

Section: Methodsmentioning

confidence: 99%

Effect of the Structure and Temperature on Corrosion Inhibition of Thiourea Derivatives in 1.0 M HCl Solution

2019

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The corrosion inhibition ability of 1-phenyl-2-thiourea (PTU) and 1,3-diisopropyl-2-thiourea (ITU) for mild steel in 1.0 M hydrochloric was studied by using the potentiodynamic polarization (PDP) curves, electrochemical impedance spectroscopy (EIS), quantum chemical calculations, and Monte Carlo simulations. Conditions which influence the capacity of corrosion inhibition including concentration, structure of thiourea derivatives, and environment temperature were taken into investigation. The highest inhibition efficiencies of PTU and ITU are 98.96 and 92.65% at a concentration of 5 × 10–3 M at 60 °C. In fact, corrosion inhibition ability of PTU is better than that of ITU in acidic solution due to the presence of the benzene ring of PTU. EIS data are very well correlated with PDP results. In addition, the higher inhibition performance with enhancing temperature and the values of ΔG0 indicated that PTU and ITU participate in chemical adsorption on the metal surface. Their adsorption process on the metal surface follow the Langmuir adsorption isotherm. Both experimental and theoretical results in this study are in good agreement.

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Section: Methodsmentioning

confidence: 99%

Effect of the Structure and Temperature on Corrosion Inhibition of Thiourea Derivatives in 1.0 M HCl Solution

2019

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“…The corrosion inhibition efficiency was calculated according to eq 15 ( 45 , 46 ) where R ct (Ω cm 2 ) and R ct(inh) (Ω cm 2 ) are charge-transfer resistances in the absence and presence of an inhibitor.…”

Section: Experimental Details and Computational Methodsmentioning

confidence: 99%

Pivotal Role of Heteroatoms in Improving the Corrosion Inhibition Ability of Thiourea Derivatives

et al. 2020

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1,3-Diphenyl-2-thiourea (DPTU) and 1-phenyl-3-(2-pyridyl)-2-thiourea (PPTU) were selected as the researched subject for investigating the effect of heteroatoms on the low carbon steel corrosion inhibition ability. Results from the potentiodynamic polarization measurements (PPM) indicate that the addition of a nitrogen atom in the benzene ring increases the corrosion inhibition efficiency of PPTU (97.2%), being higher than that of DPTU (93.1%) at the same condition of 2.0 × 10 –4 M at 30 °C. The Nyquist diagrams show that increasing the concentrations of both DPTU and PPTU will enhance the charge-transfer resistance and reduce the double-layer capacitance. The obtained data based on PPM and electrochemical impedance spectroscopy methods are in accordance to the analysis based on the scanning electrochemical microscopy images. Besides, results from quantum chemical calculations prove that the heteroatoms in the inhibitor molecules are the adsorption centers, and the benzene rings increase the electrostatic interaction between the inhibitor molecules and the steel surface. Results from Monte Carlo and molecular dynamics simulation have clarified the adsorption mechanism of DPTU and PPTU on the steel surface. Adsorption energies confirm that PPTU displays the higher inhibition ability as compared with DPTU.

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“…The achievement of this equilibrium is mandatory before performing linear polarisation and electrochemical impedance measurements. [23] The curves obtained are presented in Figure 1.…”

Section: Chronopotentiometry: Open Circuit Potential (Ocp)mentioning

confidence: 99%

Comparison between Lacunary and Saturated Keggin Polyoxometalates as Steel Corrosion Inhibitors in Chloride Solution: Contribution of the Lacuna in the Inhibition Mechanism

et al. 2020

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The effect of two lacunary Keggin polyoxometalates (K7[PW11O39].14H2O and K9[AlW11O39].15H2O) on the corrosion inhibition of XC38 steel in 0.1 M NaCl was investigated. Electrochemical methods (polarization curves and electrochemical impedance spectroscopy) showed that the presence of controlled amounts of these compounds improved protection of the steel against corrosion. These results were supported by surface analysis, where only a minor amount of rust was produced on metal surface in the presence of polyoxometalates (POMs). The lacunary POMs were more efficient compared to their saturated species, highlighting the key role played by the lacuna on the inhibition process. Efficiency of POMs (both saturated and lacunary) was explained by their ability to increase the Fe(II)/Fe(III) molar ratio in greenish protective oxide layer formed upon steel oxidation. The mechanism proposed clearly explains the higher efficiency observed with lacunary POMs, in relation to their ability to react with free Fe(III) to yield a substituted structure.

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Performances of Alkaloid Extract fromRauvolfia macrophyllaStapf toward Corrosion Inhibition of C38 Steel in Acidic Media

Cited by 42 publications

References 45 publications

Effect of the Structure and Temperature on Corrosion Inhibition of Thiourea Derivatives in 1.0 M HCl Solution

Effect of the Structure and Temperature on Corrosion Inhibition of Thiourea Derivatives in 1.0 M HCl Solution

Pivotal Role of Heteroatoms in Improving the Corrosion Inhibition Ability of Thiourea Derivatives

Comparison between Lacunary and Saturated Keggin Polyoxometalates as Steel Corrosion Inhibitors in Chloride Solution: Contribution of the Lacuna in the Inhibition Mechanism

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