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The investigation of this study deals with the synthesis using green synthetic approach, characterization and application of benzoxanthones derivative namely 9,9-Dimethyl-12-p-tolyl-8, 9,10, 12-tetrahydrobenzo[a]xanthen-1-one (TBX) for the inhibition of Q235 steel corrosion in 15% HCl under dynamic condition. The results of EIS confirmed towards the increment in Rct values with rise in concentration. Additionally, results of PDP reveals that TBX is cathodic type inhibitor. The maximum inhibitive excellency of TBX was given at 200 mg/L with the value of 92.3%. The increasing temperature tends to increase in corrosion rate. Langmuir adsorption isotherm provides the excellent fitting. The surface morphology and adsorption of TBX molecules were confirmed using scanning electron microscopy (SEM) and X-photo electron microscopy (XPS). Density functional theory (DFT) and Molecular dynamic simulation (MD) confirmed that corrosion inhibition efficiency ranking obtained for studied molecules is TBXH+> TBX.

The sour corrosion of C1018 carbon steel in CO2-saturated 3.5% NaCl + 100 ppm H2S solution and its inhibition by a low-toxic molecule, 1–benzylimidazole (1–Benz), has been investigated. Electrochem...

The present paper was designed to investigate an original synthesized ionic liquid (ILs) named 1-phenethyl-3-(3-phenoxypropyl)-1H-imidazol-3-ium bromide [Imid-3PE] Br, and 1-phenethyl-3-(4-phenoxybutyl)-1H-imidazol-3-ium bromide [Imid-4PE] Br as corrosion inhibitors. These inhibitors were evaluated against mild steel corrosion in 1 M hydrochloric acid medium using electrochemical techniques. PDP experiments revealed that the [Imid-3PE] Br and [Imid-4PE] Br behaved as mixte type inhibitors. Electrochemical impedance spectroscopy (EIS) results indicated that the both compounds showed a good inhibition of the steel surface with an inhibition efficiency of 95.8% for [Imid-3PE] Br and 96.7% for [Imid-4PE] Br at the optimum concentration. According to Langmuir isotherm model and the activation parameters, these ILs can be adsorbed onto the mild steel surface through physical and chemical bonds. The theoretical approach confirms the adsorption behavior of the studied ILs based on DFT calculation and molecular dynamic simulation.

The corrosion inhibition behavior of sodium nitrite (NaNO2) towards pure copper (99.95%) in simulated cooling water (SCW) was investigated by means of electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). NaNO2 interferes with metal dissolution and reduce the corrosion rate through the formation or maintenance of inhibitive film on the metal surface. Surface morphologies illustrated that the surface homogeneity increased on adding sodium nitrite. Sodium nitrite’s adsorption on copper surface followed the modified form of Langmuir, Freundlich and Frumkin isotherms. Physiosorption mode was involved in the corrosion protection. Electrochemical results revealed an corrosion resistance of copper increases on increasing the inhibitor concentration. The DEIS results indicated that copper corrosion mechanism could be hindered by 50% even after interval of 24 h by optimum concentration of sodium nitrite. The maximum inhibition was achieved with 2000 ppm of NaNO2. With this concentration, inhibition efficiency of up to 61.8% was achievable.

β-Cyclodextrin-based compounds are used to develop and innovate materials that protect against corrosion due to their sustainability, low cost, environmental friendliness, excellent water solubility and high inhibition efficiency. However, corrosion potentials of β-CD-based compounds were not reviewed with the modern trends. The essence of the problem is that a deep understanding of the development and innovation of β-CD-based compounds as corrosion inhibitors is very important in creating next-generation materials for corrosion protection. In this review, the fundamental behaviour, importance, developments and innovations of β-CD modified with natural and synthetic polymers, β-CD grafted with the organic compounds, β-CD-based supramolecular (host-guest) systems with organic molecules, polymer β-CD-based supramolecular (host-guest) systems, β-CD-based graphene oxide materials, β-CD-based nanoparticle materials and β-CD-based nanocarriers as corrosion inhibitors for various metals were reviewed and discussed with recent research works as examples. In addition, the corrosion inhibition of β-CD-based compounds for biocorrosion, microbial corrosion and biofouling was reviewed. It was found that (i) these compounds are sustainable, inexpensive, environmentally friendly, and highly water-soluble and have high inhibition efficiency; (ii) the molecular structure of β-CD makes it an excellent molecular container for corrosion inhibitors compounds; (iii) the β-CD is excellent core to develop the next generation of corrosion inhibitors. It is recommended that (i) β-CD compounds would be synthesized by green methods, such as using biological sustainable catalysts and green solvents, green methods include irradiation or heating, energy-efficient microwave irradiation, mechanochemical mixing, solid-state reactions, hydrothermal reactions and multicomponent reactions; (ii) this review will be helpful in creating, enhancing and innovating the next green and efficient materials for future corrosion protection in high-impact industries.

The quantitative structure–property relationship (QSPR) models of the inhibition efficiency of seventeen α-amino acids for copper in acidic medium to their calculated reactivity indicators were developed. DFT calculations and Monte Carlo simulations were employed to find out these indicators. Both multi-linear regression (MLR) and artificial neural network (ANN) methods were employed. The most relevant global descriptors were selected using the simulated annealing algorithm. The QSPR studies showed that the inhibiting performance of the investigated compounds was influenced by their electronegativity, LUMO energy, fraction of electron transferred and total negative charge. The results show that the ANN based model exhibits a great predictive performance compared with MLR model according to correlation coefficient and the root-mean-squared error. In addition, this indicates that the corrosion inhibition of copper by these α-amino acids is mainly a complex phenomenon. Moreover, by analysis of local reactivity indicators and using the ANN constructed model, ten new designed derivative compounds with their predicted inhibition efficiency were proposed. Keywords: Corrosion, Modeling, DFT, Monte Carlo, Simulated annealing, QSPR

The action of solution's pH on the inhibition property of three linear α-amino acids, namely Glycine ( Gly ), Valine ( Val ) and Leucine ( Leu ), was examined against tin corrosion in 2 wt% NaCl solution using electrochemical techniques and SEM analysis. Density functional theory (DFT) calculations and Monte Carlo simulations have been used to shed more light into the inhibition process. The results showed that the pH variation had significantly influenced the rate and the mechanism of tin corrosion, as well as, the inhibition ability of all tested biomolecules. Higher inhibition efficiency was obtained for Val at near neutral (pH 5) solution compared with acidic one (pH 2). Furthermore, the inhibition efficiency of Val decreases with increase in temperature and physisorption mode is suggested as an inhibition mechanism of tin corrosion. The formation of protective film by Val on tin surface was revealed using SEM. Moreover, the relationship between the calculated molecular electronic structure parameters and observed inhibition property were discussed. Based on the obtained theoretical results, the formation of hydrogen bonds between amino acids and tin surface could be explained the higher inhibition efficiencies obtained at pH 5 in comparison with pH 2. Depending to the solution's pH, a mechanism of the corrosion inhibition process was proposed.

The electrochemical oxidation of the Rhodamine B dye (Rh-B) was carried out using dimensionally stable type anode (DSA, Ti/Ru0.3Ti0.7O2). The work was performed using the electrochemical flow cell system. The effect of several operating factors, such as supporting electrolytes, current density, electrolysis time, temperature, and initial concentration of Rh-B dye, were investigated. The UV-visible spectroscopy and chemical oxygen demand (COD) measurements were conducted to monitor the removal and degradation of Rh-B. The best color removal achieved was found to be 98.3% after 10 min applying 3.9 mA·cm−2 as a current density using 0.07 mol·L−1 of NaCl. Meanwhile, the highest COD removal rate (93.0%) was obtained for an applied current density of 3.9 mA·cm−2 as the optimal operating condition after 180 min reaction time, with 2.98 kW h·m−3 as energy consumption. This shows that the best conditions for color removal are not certainly the same as those for the COD removal. The rises in the concentration of NaCl, and applied current increased the Rh-B color removal rate. The decline in Rh-B dye concentration followed pseudo-first-order kinetics. The obtained values of apparent rate constant were increased by increasing chloride ion concentration. It is concluded that the electro-oxidation on DSA electrode using a flow cell is a suitable process for the removal of Rh-B dye in aqueous solutions.

The comparison of the degradation efficiency of two electrodes (Ti/RuO2–IrO2 and SnO2) has been evaluated using Methylene Bleu (MB) dye. The effect of several parameters on the degradation process ...

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.

Biopolymers-based compounds were used by different manners for metal protection toward corrosion phenomena, namely via inhibiting additive and coating strategies. In the last decade, the application of these compounds or their chemically modified forms as effective replacements for toxic inorganic and organic inhibitors attracts more attention. Additionally to their intrinsic chemical stability, biodegradability, eco-friendly, low cost and renewability, biopolymers set were shown the remarkable effect to control the dissolution of several metallic materials in various corrosive environments. Among a large variety of available biopolymers, chitosan and its functionalized form, as well as its nanoparticle composites, have been reported and widely used as good anti-corrosion compounds for different metal/medium systems. In this context, the current chapter aims to shed more light on this subject.