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The ability to analyze different electrochemical corrosion phenomena, in–situ, without requiring any form of electrode perturbation has strongly attracted the attention of corrosion researchers tow...

The work reports on the study carried out to comparatively assess the corrosion inhibition efficacy of crude ethanolic extracts of date palm leaves and seeds on X60 carbon steel corrosion in 15% HCl solution at 25–60 °C. The corrosion inhibition studies was carried out using weight loss and electrochemical (potentiodynamic polarization and linear polarization resistance) techniques. Preliminary phytochemical screening was performed in order to determine the phytoconstituents present in the crude extracts. The influence of extractive solvents on the corrosion inhibition performance of the extracts was also investigated. It is found that the crude extracts of both date palm leaves and seeds contain saponins, flavonoids, cardiac glycosides and reducing sugars. Tannins is only present in the leaves and absent in the seeds while anthraquinones is absent in both extracts. The crude ethanolic extracts inhibited the corrosion of X60 steel in the aggressive 15% HCl solution with the leaves extract showing ...

Ethanolic extracts of olive leaves (OLE) in the presence of TiCl4 solution was used to form OLE – Ti nanoparticles composite (OLE-Nano). The particle size of Ti nanoparticles in the composi...

YILDIZ, MESUT/0000-0001-6964-6705; KAYA, ERTUGRUL/0000-0003-1579-6411; Gerengi, Husnu/0000-0002-9663-4264; Solomon, Moses/0000-0002-3251-8846; Umoren, Saviour/0000-0002-8564-4897 WOS: 000425767400010 The efficacy of 1-butyl-1-methylpiperidinium tetrafluoroborate (BMPTFB) in retarding St37 steel corrosion in HCl environment has been examined using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), dynamic-EIS (DEIS), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) techniques. Results from all applied methods reveal that BMPTFB is effective in suppressing St37 dissolution in the studied corrosive medium. Inhibition efficiency of 88% has been achieved by 4mM BMPTFB. From DEIS results, BMPTFB is found to perform better as corrosion inhibitor at longer immersion time. The charge transfer resistance of the metal is raised in the presence of 4mM BMPTFB from 378 to 744 cm(2) at 1h and further increased to 867 cm(2) at 4h. BMPTFB, according to PDP result behaves as mixed-type corrosion inhibitor. Corrosion inhibition by BMPTFB is via adsorption which can best be explained using El-Awady kinetic/thermodynamic adsorption isotherm. K-ads and values indicate that physisorption is the mechanism of adsorption of BMPTFB molecules onto St37 surface. The presence of BMPTFB molecules on St37 surface has been verified by SEM and FTIR. Duzce University Research Council for Science and Technology (BAP) [2016.06.05.492] The authors acknowledge the following: (i) Dr Kazimierz Darowicki and Pawel Slepski for providing the DEIS software and (ii) Duzce University Research Council for Science and Technology (BAP) for the financial support (Project No. 2016.06.05.492).

The toxic nature of most organic and inorganic corrosion inhibitors has necessitated the search for corrosion inhibitors with an excellent environmental profile. The present work is focused on the widening utilization of plant extracts for metallic corrosion control and reports on the corrosion inhibition effect of mustard seed extract (MSE) for typical X60 pipeline steel in 2 M HCl and 1 M H2SO4 solutions. Gravimetric and electrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization) methods were employed. The effect of immersion time and temperature on the corrosion inhibition effect of the plant extract was also studied. Results obtained show that MSE inhibited the corrosion of steel in both media which was more pronounced in H2SO4 than in HCl environment. Inhibition efficiency increased with increase in the concentration of the extract but decreased with increase in temperature. The potentiodynamic polarization studies revealed that MS...

The performance of 1-[(2-hydroxyethyl) amino]-2-(salicylideneamino)ethane (HAS) as a corrosion inhibitor for carbon steel in CO2-saturated 3.0% NaCl solution under aerated and deaerated conditions was studied using weight loss and potentiodynamic polarization methods at different temperatures. The results obtained show that in aerated environment, HAS acts as an effective corrosion inhibitor for carbon steel in CO2-saturated brine solution and accelerate corrosion under deaerated condition. Inhibition efficiency (IE%) increased with increase in HAS concentration but decreased with increase in temperature. Corrosion inhibition action was via the adsorption of HAS on the metal’s surface which follows the Langmuir adsorption isotherm model. Polarization curves indicate that HAS functions as a mixed-type inhibitor.

Interaction of organic molecules with the surface of metals plays important role in many applications. In particular, surface protective applications need much explanation from both experimental and theoretical point of view. Herein, we have investigated the surface adsorption characteristics and corrosion inhibition behavior of two new benzimidazole derivatives namely 2-(2-Bromophenyl)-1H-benzimidazole (BPBA) and 2-(2-Bromophenyl)-1-methyl-1H-benzimidazole (BPMA) on mild steel in 0.5 M HCl solution using experimental and theoretical approach. Electrochemical and weight loss experiments were used to elucidate the corrosion inhibition potentials of BPBA and BPMA. Attenuated total reflectance-Fourier transform infrared spectroscopy, contact angle, scanning electron microscopy, and X-ray photoelectron spectroscopy measurements were performed to confirm the adsorption of BPBA and BPMA on mild steel surface. Computer simulations were further employed to provide additional insights into the mechanism of interac...

The inhibition performance of poly (methacrylic acid) (PMAA) and the effect of addition of iodide ions on the inhibition efficiency for mild steel corrosion in 0.5 M H2SO4 solution were investigated in the temperature range of 303–333 K using electrochemical, weight loss, scanning electron microscopy (SEM), and water contact angles measurements. The results show that PMAA is a moderate inhibitor for mild steel in 0.5 M H2SO4 solution. Addition of small amount of KI to PMAA significantly upgraded the inhibition efficiency up to 96.7%. The adsorption properties of PMAA and PMAA + KI are estimated by considering thermodynamic and kinetic parameters. The results reveal that PMAA alone was physically adsorbed onto the mild steel surface, while comprehensive adsorption mode characterized the adsorption of PMAA + KI. Adsorption of PMAA and PMAA + KI followed Temkin adsorption isotherm. The SEM and water contact angle images confirmed the enhanced PMAA film formation on mild steel surface by iodide ions.

Activated carbon has been prepared from plantain peels unripe, a biowaste from confectioneries for investigation of its adsorption efficiency in binary system of lead (II) and 3,7-Bis(dimethylamino)-phenothiazin-5-ium chloride as common water pollutants. The prepared carbons were characterized using nitrogen adsorption, FTIR spectroscopy, and XRD. Batch adsorption experiments were conducted to determine most probable conditions of adsorption maximum via varying adsorbent concentration, initial pollutants concentration, and pH of adsorption. Adsorption was found to be dependent on the factors studied. Favorable adsorption was recorded at initial concentration of 300 mg/dm3 after 30 min. Equilibrium and kinetic data were modeled using well-known isotherm and kinetic models. Results deviated largely from Langmuir monolayer, Freundlich multilayer and extended Langmuir isotherm models suggesting a mutual interaction of the adsorbates in solution which is shown with data obtained from competitive adsorp...

The corrosion inhibition effect of red apple (Malus domestica) fruit extract for mild steel in hydrochloric acid was investigated by gravimetric and electrochemical methods at 30–60°C. Inhibition efficiency increased with the increase in concentration and temperature. Polarization curves indicate that the extract functions as mixed-type inhibitor. The adsorption of the extract onto mild steel surface followed Langmuir adsorption isotherm model. Chemisorption mechanism is proposed based on the trend of inhibition efficiency with temperature. Quantum chemical calculations and molecular dynamics simulations have been used to provide insights into the mechanism of interaction of the major extract components with mild steel.

Two grades of polyvinyl alcohol (PVA) namely partially hydrolyzed (designated as PVA-I) and fully hydrolyzed (designated as PVA-II) were studied with the aim of determining the influence of PVA degree of hydrolysis on the corrosion inhibition effect of mild steel in HCl medium. The investigation was carried out using weight loss, electrochemical impedance spectroscopy, potentiodynamic polarization (PDP), and linear polarization resistance techniques. Results obtained indicate that the two grades of PVA inhibited the acid-induced corrosion of mild steel. Inhibition efficiency increased with increase in the PVAs concentration but decreased with increase in temperature. Results from all the techniques employed were in close agreement and revealed that corrosion inhibition effect followed the order PVA-I > PVA-II. PDP data show that both grades of PVA act as a mixed-type inhibitor. Impedance spectra show a high frequency capacitive loop related to the charge-transfer process of the metal corrosion and the dou...

Humic acids (HAs) extracted from cow, goat, and poultry dung were studied. Extraction was performed by treating the source materials with acid hydrolysis using hydrochloric acid (HCl) before alkaline extraction with sodium hydroxide (NaOH). Yields of 3.33, 2.67, and 1.28% dry weight were obtained from cow, goat, and poultry dung respectively. The extracted humic acids were characterized using Fourier transform-infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopy techniques. The results obtained were in good agreement with commercial HA (Sigma-Aldrich). The humic acid extracted from cow dung was used to evaluate its corrosion inhibition potential for alkaline-induced corrosion of 3SR aluminum alloy using weight loss and electrochemical (potentiodynamic polarization) techniques at 30°–60°C. Results obtained show that the humic acid functions as an excellent corrosion inhibitor for aluminum alloy in 0.1 M NaOH solution. Corrosion inhibition efficiency increased with increase in humic acid concentra...

The corrosion protection of carbon steel in 1 M HCl by 1-octadecanethiol (ODT) alone and in combination with iodide ions was investigated at ambient temperature using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. Results obtained showed that ODT alone offered low corrosion protection ability at very low concentrations. However, on addition of iodide ions, the corrosion protection potential was enhanced due to synergistic effect. Potentiodynamic polarization data revealed that ODT acts as mixed-type inhibitor influencing both the cathodic hydrogen evolution and anodic metal dissolution reactions. Adsorption of ODT onto the carbon steel surface followed Langmuir adsorption isotherm model. The existence of synergism phenomenon between ODT and iodide ions was confirmed from synergism parameter, which was found to be greater than unity. Quantum chemical calculations provide greater insight into the mechanism of electron transfer and mechanistic aspects of ODT on steel surface.

The corrosion inhibition of mild steel in hydrochloric acid solution in the presence of three different molecular weights of polyvinyl alcohol (PVA) designated as PVA-I, PVA-II, and PVA-III corresponding to 14,000, 72,000, and 125,000 g mol−1, respectively, was investigated using electrochemical impedance spectroscopy, linear polarization resistance (LPR), and potentiodynamic polarization techniques at 25°C. It was found that PVA of different molecular weights inhibited the corrosion of mild steel in the acid environment. Inhibition efficiency (η%) increases with increase in concentration of the polymers. LPR measurements clearly show that inhibition efficiency increases with increasing molecular weight in the order PVA-III > PVA-II > PVA-I. Polarization curves indicate that PVA functions as a mixed inhibitor affecting both the anodic metal dissolution and cathodic hydrogen evolution partial reactions of the corrosion process. The experimental data obtained fitted well into Langmuir adsorption isotherm mo...

Corrosion inhibition mechanism of aluminium in H2SO4 by polyacrylic acid (PAA) in the absence and presence of iodide ions was investigated using in-situ atomic force microscopy (AFM). Results indicate that PAA inhibited the corrosion of aluminium by adsorption onto the aluminium surface. Inhibition efficiency of PAA was found to enhance on addition of iodide ion which could be ascribed to synergistic effect. In-situ AFM morphology of the surface film suggests that PAA in the presence of iodide ion was adsorbed on aluminium surface after taking a more ordered arrangement, thus providing a more uniform coverage at potentials below and above potential of zero charge.

The inhibition of a substituted naphthol compound, 4-(4-nitrophenylazo)-1-naphthol (44NIN), on the corrosion of aluminium (Al) in a basic medium was studied by classical chemical (gravimetric) and spectrophotometric (UV–Vis and FTIR) methods at 303–333 K. 44NIN demonstrated an excellent inhibiting property to Al corrosion in the aerated binary alkaline solution as shown from the results. The inhibition efficiency was found to increase with the azo dye concentration but not with temperature. Thermodynamic and adsorption evaluation for this inhibition process were accessed and thoroughly discussed. The UV–visible absorption spectra of the solution containing this dye after the immersion of Al specimen indicate the possible formation of a 44NIN–Fe type complex. The FTIR was carried out of the dye and protective film formed on the surface of the metal in the electrolyte containing the dye after a 72 h immersion period. These results show a correlation between the inhibitive effect and molecular structural inf...

Corrosion inhibition of aluminium in 1 M HCl by coconut coir dust extract (CCDE) was studied using weight loss and hydrogen evolution techniques at 30 and 60°C. It was found that the studied extract exhibits a very good performance as inhibitor for aluminium corrosion in 1 M HCl. Results show that the inhibition efficiency increases with increasing temperature and concentration of the extract. Inhibitive effect was afforded by adsorption of the extracts' components which was found to accord with Langmuir adsorption isotherm. Inhibition mechanism is deduced from the temperature dependence of the inhibition efficiency and was further corroborated by the values of activation parameters obtained from the experimental data.

The adsorption of fluconazole (FLU) on aluminum surface from 0.1 M HCl solution was studied using chemical technique at 30°–50°C. The values for free energy of adsorption, , were calculated at each surface coverage, θ, of the studied compound by applying the mathematical model of the Bockris-Swinkels adsorption isotherm. The phenomenon of physical adsorption is proposed from the value of Gibbs free energy, , obtained from the Bockris-Swinkels adsorption equation and the mean adsorption energy, E, using the adsorption isotherm model of Dubinin-Radushkevich (D-R). A zero-order kinetics relationship with respect to aluminum was obtained with and without FLU from the kinetic treatment of the data.

The corrosion inhibitive effects of Pachylobus edulis exudate gum for mild steel in 2 M H2SO4 and influence of potassium halide additives on the inhibition efficiency were investigated using hydrogen evolution and thermometric methods at 30°–60°C. Inhibition efficiency was determined by comparing the corrosion rates in the absence and presence of additives. The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition. It was found that the exudate gum acts as an inhibitor for acid-induced corrosion of mild steel. Inhibition efficiency (%I) of the exudate gum increased with an increase in concentration of the exudate gum and synergistically increased on addition of potassium halides but decreased with increase in temperature. Inhibitor adsorption characteristics were approximated by Temkin adsorption isotherm at all the concentrations and temperatures studied. The phenomenon of physical adsorption is proposed from the activation parameters obtained.

A biodegradable polymer mud was prepared using Millet starch pre-gelatinized in the absence of a solvent. The filtration and rheological properties of the mud were studied at 25°–200°C temperature range and at 0.01–0.05 g/mL concentration of starch using filter loss and viscometric methods respectively. Experimental results showed that the new mud has better filtration control behavior and thermal stability at all the temperatures than widely used mud prepared with hydroxy propyl–modified starch. The mud displayed thermal degradation at 200°C. The values of flow index were found to be less than 1.0, showing non-Newtonian and pseudoplastic flow behavior of the mud. Shear stress and yield stress increase with increase in concentration. Viscosity decreases with increasing shear rate, showing shear thinning behavior of the mud. The polymer mud obeyed Henri Darcy and API models for static filtration as well as power law and Herschel-Bulkley models for fluid rheology. The new mud is purer and more suitable for ...

The 12th International Dendritic Cell (DC) symposium (DC2012, www.DC2012.kr), organized by Ho-Youn Kim (President), Hyunah Lee (Secretary General), and Yong-Soo Bae (Scientific Organizer), was held...