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Chitosan (CS) was cross-linked using cinnamaldehyde (Cinn) in a single step procedure following microwave irradiation to produce cinnamaldehyde-modified chitosan (Cinn-CS). The synthesized Cinn-CS was used as a novel corrosion inhibitor for copper in 1 M hydrochloric acid. A comprehensive electrochemical investigation using the impedance measurements, and potentiodynamic polarization was undertaken, supported with surface analysis and computational studies. The inhibitor Cinn-CS functioned by adsorption on the copper surface and showed an inhibition efficiency of >89% at a dose of 1000 mgL -1 . The charge transfer resistance showed a rise with increase in inhibitor dosage to the corrosive medium, and the corrosion currents showed a significant decrease with the addition of the inhibitor. The Cinn-CS displayed a mixed type of inhibition performance with cathodic nature. The study of the copper surface using scanning electron microscopy depicted a considerably smooth morphology in the presence of the adsorbed Cinn-CS. The computational studies indicated that the Cinn-CS Schiff base shows better adsorption behavior compared to the parent molecules of chitosan and cinnamaldehyde and can show an inhibition performance in the neutral, and the protonated form., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The influence of chitosan on the copper corrosion in sulfide polluted synthetic seawater (SSW) containing 20 ppm of sulfide has been investigated for the first time. Potentiodynamic polarization measurements, electrochemical impedance spectroscopy at the open circuit potential and weight loss measurements were employed to assess the corrosion inhibition ability of chitosan. The impedance studies revealed that in the presence of chitosan at various concentrations, the charge transfer resistance increases. At a concentration of 800 ppm, chitosan exhibited a corrosion inhibition efficiency of 89% following physical adsorption. The influence of temperature and immersion time was studied in sulfide-contaminated synthetic seawater and significant inhibition was observed even after 90 days. SEM-EDS studies confirm the absence of the deterioration products on copper surface., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Abstract: The corrosion inhibition of copper and zinc in 0.1M HNO3 by 1,2,3,4-tetrazole (TTZ) and some of its derivatives has been analysed in a comparative study. Two experimental techniques have been used such as weight-loss and electrochemical polarization measurements. The results obtained reveal that the addition of these compounds reduces preferentially the corrosion of Cu rather than that of Zn. The adsorption of tetrazolic compounds on a copper surface was more favourable than their adsorption on a zinc surface. Moreover the inhibition efficiency calculated for copper was found to attain 95% in the presence of 1-phenyl-5-mercapto-1,2,3,4-tetrazole (PMT) while it remains constant at 1% for all compounds tested using zinc as electrode. Relationship between molecular structure and their inhibition efficiency was elucidated by quantum chemical calculations using the density functional theory (DFT). [Copyright &y& Elsevier]

Abstract: The inhibition effect of five amino acids (AA) on the corrosion of copper in molar nitric solution was studied by using weight loss and electrochemical polarization measurements. Valine (Val) and Glycine (Gly) accelerate the corrosion process; but Arginine (Arg), Lysine (Lys) and Cysteine (Cys) inhibit the corrosion phenomenon. Cysteine is the best inhibitor. Its efficiency increases with the concentration to attain 61% at 10−3 M. Correlation between the quantum chemical calculations and inhibition efficiency was discussed using semi-empirical methods (AM1 and MNDO). [Copyright &y& Elsevier]

Abstract The study of the inhibitory power of the Pulp of Jujube (PJ) extract of the plant Zizyphus Lotus with respect to the corrosion of copper in 1 M hydrochloric medium has been realized. This study was conducted by stationary and transients electrochemical measurements, weight loss and atomic absorption spectroscopy techniques. Scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), Fourier transform infrared (FT-IR) and atomic force microscopy (AFM) studies were used to characterize the surface of uninhibited and inhibited copper specimens. The results showed that the inhibition increases with PJ extract concentration reaching a maximum of 93% at a concentration of 1 g L−1. The obtained results indicate that PJ extract can act as a good green corrosion inhibitor for copper in 1 M HCl. The effect of temperature was also investigated and thermodynamic parameters were determined and discussed. Graphical abstract Unlabelled Image Highlights • The PJ extract is highly efficient corrosion inhibitor. • The inhibitory efficiency reaches a value of 93% at 1 g L−1. • Polarization studies revealed that PJ acts as a cathodic type. • The temperature effect revealed that the mode of adsorption is a physical nature. • The inhibition mechanism is studied using SEM/EDS, AFM and FT-IR surface analysis. [ABSTRACT FROM AUTHOR]

The anti-corrosion behavior of sodium alginate (SA) on copper in the 1 M hydrochloric medium was carried out using weight loss and electrochemical measurements. The obtained results show that the inhibition increases with SA concentration and then reaches a maximum of 83% at a concentration of 0.1 mg L − 1 . The effect of temperature on the reactions of copper corrosion inhibition and analyzing the thermodynamic parameters revealed that the mode of adsorption has a physical nature and obeys the Langmuir isotherm. The surface morphology was performed by scanning electron microscopy coupled with energy dispersive X-ray spectrometry and atomic force microscopy. To better understand the adsorption mechanism, describing the relationship between inhibitory ability and the molecular structure of SA, quantum calculations using density functional theory were performed. Monte Carlo simulation approache was performed to know well of the relationship between the inhibition ability and molecular structure of alginate. [ABSTRACT FROM AUTHOR]

An effective and eco-friendly Jujube shell (JS) extract was studied as a corrosion inhibitor for copper in 1 M hydrochloric acid. This work was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss coupled with atomic absorption spectroscopy techniques. Atomic force microscopy (AFM), Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) revealed the surface morphology in the presence and absence of inhibitor on the metal surface. The experimental results reveal that the JS extract act as a cathodic-type with an inhibition efficiency (IE%) up to 91% for 2 g L−1 at 298 K. In addition, this extract shows good inhibitory activity at a wide range of temperatures. The thermodynamic parameters were determined and discussed. Meanwhile, Monte Carlo simulation and Quantum chemical calculations by application of density functional theory (DFT) were carried out to help better understand the inhibition mechanism of this extract on the copper surface. The results indicated the feasibility of using the Jujube shell (JS) extract as a corrosion inhibitor in acid environment. Unlabelled Image • The inhibitory efficiency reaches a value of 91% at 1 g/L. • Polarization studies revealed that JS acts as a cathodic type. • The JS extract is highly efficient corrosion inhibitor. • The inhibition mechanism is studied using SEM/EDS and AFM surface analysis. [ABSTRACT FROM AUTHOR]