Synthesis,Surface Properties,and Inhibiting Action of Novel Nonionic Surfactants on Carbon Steel Corrosion in 1 M Hydrochloric Acid Solution

In the present study novel nonionic surfactants were synthesized, characterized, and tested as corrosion inhibitors for carbon steel in 1 M HCl solution. The inhibiting performances of these surfactants were studied by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The adsorption of these inhibitors was well described by Langmuir adsorption isotherm, and the kinetic parameters were calculated and discussed. The inhibition efficiency (IE) was found to rise with increasing the concentration of these inhibitors. Polarization measurements revealed that the inhibitors acted as mixed-type inhibitors. The efficiencies obtained from the impedance measurements were in good agreement with those obtained from the weight loss and potentiodynamic polarization techniques which prove the validity of these tools in the measurements of the tested inhibitors. The surface parameters of the synthesized nonionic surfactants were investigated and the results showed that these surfactants have lower values of surface tension and are effective as wetting and emulsifying agents.     

The Effect of Non Ionic Surfactants Containing Triazole, Thiadiazole and Oxadiazole as Inhibitors of the Corrosion of Carbon Steel in 1M Hydrochloric Acid

In the present investigation novel nonionic surfactants were synthesized, characterized and tested as inhibitors of the corrosion of carbon steel in 1M HCl solution. The inhibition action of these surfactants was studied by weight loss, galvanostatic polarization and electrochemical impedance spectroscopy. The adsorption of the inhibitors was well described by the Langmuir adsorption isotherm and the adsorption isotherm parameters were determined at different temperatures. The inhibition efficiency was found to rise when increasing the concentration of these compounds and decreasing the temperature. The effect of temperature on the inhibition efficiency of the corrosion process was studied and the values of some activated thermodynamic parameters were calculated to elaborate the mechanism of inhibition. The synthesized nonionic surfactants exhibit good surface and antimicrobial properties.     

Corrosion Inhibition Efficiency,Electrochemical and Quantum Chemical Studies of Some New Nonionic Surfactants for Carbon Steel in Acidic Media

In this work, three types of nonionic surfactant as corrosion inhibitors were synthesized. The chemical structure of the prepared inhibitors was confirmed using FT‐IR and ¹H‐NMR spectroscopy. The surface tension and thermodynamic properties of these inhibitors were investigated. The corrosion inhibition efficiency of these surfactants was investigated on a carbon steel surface in 1 M HCl solution by weight loss and electrochemical measurements. Untreated and treated steel surfaces were characterized by scanning electron microscopy. Results show that the inhibition efficiency of the prepared inhibitors increases with increasing the ethylene oxide units. Also, the potentiodynamic polarization curves indicated that the investigated inhibitors behave as a mixed type inhibitor. Adsorption of these surfactants on the carbon steel surface was found to obey Langmuir's adsorption isotherm. The computed quantum chemical properties viz., electron affinity (EA), highest occupied molecular orbital (E_HOMO), the lowest unoccupied molecular orbital (E_LUMO), energy gap ΔE = E_HOMO ? E_LUMO, dipole moment (μ), polarizability and total energy (E_T) show good correlation with experimental inhibition efficiency.     

CORROSION INHIBITION OF STEEL PIPELINES IN OIL WELL FORMATION WATER BY A NEW FAMILY OF NONIONIC SURFACTANTS

A new family of nonionic surfactants was synthesized and evaluated as corrosion inhibitors for steel pipelines in oil well formation water. Polarization data show that the selected surfactants act as mixed-type inhibitors. EIS results show that the change in impedance parameters (R_t and C_dl) with the concentration of the surfactants studied is indicative of the adsorption of surfactant molecules on carbon steel surface, leading to formation of a good protective film. The properties of this film were studied by various surface analysis tools. Finally, the relation between the surface properties of the inhibitor molecules and corrosion inhibition efficiency is discussed.     

New Biodegradable Nonionic-Anionic Surfactants Based on Different Fatty Alcohols as Corrosion Inhibitors for Aluminum in Acidic Medium

Two series of eco-friendly nonionic anionic surfactants based on itaconic acid and 1, 6 hexane diol were synthesized. The chemical structures of the prepared surfactant were confirmed by FTIR and ¹H NMR spectroscopy. The prepared surfactants were evaluated to prevent the corrosion of aluminum in 1.0 M HCl solution by electrochemical and chemical methods. The data obtained showed that the prepared compounds have good inhibition efficiency (IE%) even at 10⁻⁵ M concentrations and act as mixed-type inhibitors, they do not affect the mechanism of the electrode processes, as well as the IE% increase by increasing the concentrations of the inhibitors, immersion time, and hydrophilic chain length. The high inhibition efficiency is due to the adsorption of the inhibitors molecules on the metal surface and the formation of a protective film. The surface activities of these compounds were also investigated and were correlated to their inhibition efficiencies and chemical structure. Through studying biodegradability of the synthesized surfactants we find that they are readily biodegradable in the environment and thus they are considered as eco-friendly corrosion inhibitors. Finally, the effect of the addition of these compounds on the aluminum surface was identified by atomic force microscopy (AFM) technique.     

Novel Biobased Nonionic Surfactants: Synthesis,Surface Activity and Corrosion Inhibition Efficiency Against Aluminum Alloy Dissolution in Acidic Media

Four nonionic surfactants were prepared from the reaction of propylene oxide with oleic acid, linoleic acid, and the free fatty acid mixture from hydrolysis of jatropha oil. The chemical structures of the prepared surfactants were confirmed using IR and NMR spectroscopy. The surface activities of the prepared surfactants were dependent on the polypropylene oxide chain length and also on the nature of the alkyl chains. The nonionic surfactants were evaluated at different concentrations as corrosion inhibitors against the corrosion of Al 6061 aluminum in 2 M HCl solution. The corrosion inhibition tendencies of the surfactants were completely dependent on the fatty acid ratio in the jatropha oil and also on the polypropylene oxide chain length. The corrosion inhibition efficiencies of the surfactants were correlated to their chemical structure and their surface activities.     

A Corrosion Inhibition Study of a Novel Synthesized Gemini Nonionic Surfactant for Carbon Steel in 1 M HCl Solution

In this study, a gemini nonionic surfactant was synthesized as a corrosion inhibitor for carbon steel in 1 M HCl. Surface properties of the synthesized gemini nonionic surfactant were determined by using surface tension. The results showed that the gemini nonionic surfactant has good surface active properties. The corrosion inhibition effect of the synthesized inhibitor on carbon steel was evaluated by using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and weight loss methods. The characterization of the film formed on the steel surface was carried out by scanning electron microscope (SEM) methods. The inhibitor molecules were adsorbed physically onto a carbon steel surface according to the Langmuir adsorption isotherm. The results revealed that the inhibitor acted as a mixed-type inhibitor. It was found that the inhibition efficiency increases with an increase in inhibitor concentration and decreases with increasing temperature. Thermodynamic parameters were calculated to elucidate the inhibitive mechanism.     

Synthesis and Evaluation of 4-Diethyl Amino Benzaldehyde Schiff Base Cationic Amphiphiles as Corrosion Inhibitors for Carbon Steel in Different Acidic Media

A novel series of cationic surfactants containing Schiff base groups were synthesized by condensation of fatty amines namely: dodecyl, tetradecyl, hexadecyl and octadecyl amine and 4-diethyl aminobenzaldehyde. The chemical structures of these surfactants were confirmed using elemental analysis, FTIR spectra, ¹H-NMR and atomic absorption spectroscopy. Surface properties of the synthesized compounds were determined using surface tension techniques. The results of the surface tension measurements showed good surface behaviors of these compounds in their aqueous solutions. The surface activities were found to be greatly influenced by the chemical structures of the synthesized compounds. The synthesized cationic Schiff bases were evaluated as corrosion inhibitors for carbon steel in different acidic media (HCl and H₂SO₄) at different doses (400, 200, 100, 50, 25 ppm). The corrosion inhibition efficiencies of these inhibitors were calculated using the corrosion rates of the carbon steel in the studied media and found in the acceptable range of the commercially used inhibitors. Also the chemical structure of these inhibitors was found of great influence on their inhibiting efficiency.     

Synthesis of Quaternary,Long-Chain N-Alkyl Amides and Their Corrosion Inhibition in Acidic Media

New cationic surfactants were synthesized by the quaternization of a number of straight-chain amide derivatives with triethylamine or pyridine. The corrosion inhibition tests of the surface-active compounds were performed at room temperature for 24 h on carbon steel coupons in acidic media using the gravimetric method. The acidic media used were 1.5 M HCl and 1.5 M H₂SO₄. Almost all of the synthesized cationic surfactants showed efficient inhibition of corrosion in the test. To establish the inhibition efficiencies of the inhibitors, surface characterization studies (contact angle measurements, SEM analysis and optical profilometer images) of the metal coupons used were performed.     

Surface protection of copper in acid medium by azoles and surfactants

The influence of derivatives of 1,2,4 triazole, 3-amino 1,2,4-traizole (ATA), 3-amino 5-mercapto 1,2,4 triazole (AMT) and 3-amino 5-methylthio 1,2,4 triazole (AMTT) and ionic surfactants cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) on the corrosion control of copper in acidic solution was investigated by gravimetric and electrochemical methods. The combined effect of triazoles and surfactants was also evaluated. Electrochemical parameters like corrosion potentials corrosion current density, corrosion rates and inhibition efficiencies were determined. The results reveal the fact that of all triazoles AMTT shows best inhibition and anionic surfactant SDS protects the surface better than the cationic surfactant CTAB. The polarisation data reveal that all inhibitors behave as a mixed type inhibitor. Adsorption of these inhibitors on the surface of copper is found to obey the Langmuir adsorption isotherm. A marked inhibition synergism effect is shown by all the combinations of triazole and surfactant.     

Enhancing of Corrosion Inhibition and the Biocidal Effect of Phosphonium Surfactant Compounds for Oil Field Equipment

It is well known that tetra hydroxymethyl phosphonium sulfate (THPS) is commonly used in oil fields as a biocide for sulfate-reducing bacteria (SRB), but it has low corrosion inhibition. In this study, four phosphonium surfactant compounds were synthesized via a coupling reaction between THPS and different fatty acids namely: decanoic, dodecanoic, palmitic and stearic acids to produce the corresponding surfactants. The chemical structure of the synthesized surfactants was confirmed using FTIR and ¹H-NMR spectroscopy. The surface activity of the prepared compounds was determined by surface tension measurements. The critical micelle concentration (CMC) of each surfactant compound was determined. The corrosion inhibition of the synthesized compounds on carbon steel in 0.5 M HCl was studied by weight loss measurements, potentiodynamic and electrochemical impedance spectroscopy. The effect of the inhibitor concentration and hydrophobic chain length on the their efficiency was also studied. It was found that the CMC of each compound depends on its chemical structure. It was also found that the corrosion inhibition efficiency depends on both of concentration and molecular structure of the inhibitors. Polarization curves revealed that the inhibitors used represent mixed-type inhibitors, which hinder the cathodic and anodic parts of the corrosion reaction in acidic media. Adsorption of used inhibitors leads to a reduction in the double layer capacitance and an increase in the charge transfer resistance. Also the biocidal effect of these compounds was enhanced.     

Electrochemical study on the effect of bipyridine dicarboxylic acid and its cobalt complex on the corrosion behaviour of carbon steel in acidic medium

The 2,2′-bipyridine-3,3′-dicarboxylic acid (bida) and its cobalt complex (Co-bida) were tested as corrosion inhibitors for N80 carbon steel in sulphuric acid solution by electrochemical polarization and electrochemical impedance spectroscopy method. The results indicate that the complex and ligand inhibit the corrosion of mild steel in H₂SO₄ solutions and the extent of inhibition increases with inhibitor concentration and decreases with temperature. The inhibition efficiency of the inhibitors follows the trend Co-bida > bida. A mixed-inhibition mechanism is proposed for the inhibitive effects of the compounds. The adsorption characteristics of the inhibitors were approximated by Temkin isotherm. Morphological study of the carbon steel electrode surface was undertaken by scanning electron microscope and the interfacial species formed on the surface in the presence of inhibitors analyzed by infrared spectroscopy.     

Novel Imidazolium-Based Gemini Surfactants: Synthesis, Surface Properties, Corrosion Inhibition and Biocidal Activity Against Sulfate-Reducing Bacteria

Three novel imidazolium-based gemini surfactants had been synthesized and characterized using different spectroscopic techniques. The surface properties of the synthesized surfactants were determined using surface tension measurements at 20 °C. The surface parameters including critical micelle concentration (CMC), π _CMC, Pc₂₀, Γ_max and A _min were determined. The synthesized compounds were evaluated as corrosion inhibitors for carbon steel in 0.5 M HCl solution using the weight loss and polarization techniques. The biological activity of these surfactants was evaluated against sulfate reducing bacteria using most probable number method. The results indicate that the synthesized compounds have good surface properties and are proper corrosion inhibitors for low carbon steel, with a high inhibition efficiency observed around their CMC. These compounds exhibit a significant biocidal activity against sulfate reducing bacteria.     

Corrosion inhibition of carbon steel in hydrochloric acid by furan derivatives

The efficiency of three furan derivatives (2-methylfuran, furfuryl alcohol and furfurylamine), as corrosion inhibitors for carbon steel in 1 M HCl, has been determined by gravimetric and electrochemical measurements. These compounds inhibit corrosion even at very low concentrations, and furfuryl alcohol is the best inhibitor. Polarization curves indicate that all compounds are mixed inhibitors, affecting both cathodic and anodic corrosion currents. Adsorption of furan derivatives on the carbon steel surface is in agreement with the Langmuir adsorption isotherm model, and the calculated Gibbs free energy values confirm the chemical nature of the adsorption. The structural and electronic properties of these inhibitors, obtained using AM1, PM3, MNDO and MINDO/3 semi-empirical self-consistence field methods, are correlated with their experimental efficiencies.     

ac impedance, X-ray photoelectron spectroscopy and density functional theory studies of 3,5-bis(n-pyridyl)-1,2,4-oxadiazoles as efficient corrosion inhibitors for carbon steel surface in hydrochloric acid solution

The corrosion inhibition properties of a new class of oxadiazole derivatives, namely 3,5-bis(n-pyridyl)-1,2,4-oxadiazoles (n-DPOX) for C38 carbon steel corrosion in 1 M HCl medium were analysed by electrochemical impedance spectroscopy (EIS). An adequate structural model of the interface was used and the values of the corresponding parameters were calculated and discussed. The experimental results showed that these compounds are excellent inhibitors for the C38 steel corrosion in acid solution and that the protection efficiency increased with increasing the inhibitors concentration. Electrochemical impedance data demonstrate that the addition of the n-DPOX derivatives in the corrosive solution decreases the charge capacitance and simultaneously increases the function of the charge/discharge of the interface, facilitating the formation of an adsorbed layer over the steel surface. Adsorption of these inhibitors on the steel surface obeys to the Langmuir adsorption isotherm. X-ray photoelectron spectroscopy (XPS) and the thermodynamic data of adsorption showed that inhibition of steel corrosion in normal hydrochloric solution by n-DPOX is due to the formation of a chemisorbed film on the steel surface. Quantum chemical calculations using the Density Functional Theory (DFT) and the Quantitative Structure Activity Relationship (QSAR) approach were performed on n-DPOX derivatives to determine the relationship between molecular structure and their inhibition efficiencies. The results of the quantum chemical calculations and experimental inhibition efficiency were subjected to correlation analysis and indicate that their inhibition effect is closely related to E_HOMO, E_LUMO, and dipole moment (μ).     

Spectroscopic Investigations of Physicochemical Interactions on Mild Steel in an Acidic Medium by Environmentally Friendly Green Inhibitors

The influences of Polycarpaea corymbosa (PC) and Desmodium triflorum (DT) leaf extracts on the corrosion behavior of mild steel (MS) in 1.0 M HCl was investigated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The effect of temperature on the corrosion behavior of MS in 1.0 M HCl with the addition of plant extracts was studied in the temperature range of 300 K–320 ± 1 K. The results revealed that PC and DT were excellent green inhibitors and the inhibition efficiencies obtained from weight loss and electrochemical experiments were in good agreement. Inhibition efficiencies up to 91.78 % for PC and 92.99 % for DT were obtained. Potentiodynamic polarization studies revealed that both the inhibitors behaved as mixed‐type inhibitors. Adsorption behavior of these green inhibitors on the MS surface was found to obey the Langmuir adsorption isotherm. The thermodynamic parameter values of free energy of adsorption (?G_ads) and enthalpy of adsorption (?H_ads) revealed that each inhibitor was adsorbed on the MS surface via both chemisorption and physisorption mechanisms. The adsorption mechanism of inhibition was supported by FT–IR, UV–Visible, WAXD and SEM–EDS.     

Synthesis of undecanoic acid phenylamides as corrosion inhibitors

Non‐substituted or mono‐substituted 11‐cyano or 11‐thiocyanato undecanoic acid phenylamide derivatives were synthesized and characterized with their FT‐IR and ¹H‐NMR spectra. Thereafter, their corrosion prevention efficiencies were investigated. All compounds were tested with steel coupons in acidic medium by a gravimetric method. Acidic tests were done with a medium concentration of 2 M HCl for 5 h at variable temperatures and inhibitor concentrations. The corrosion prevention efficiencies of the inhibitors were compared according to their chemical structures and the corrosion inhibition mechanism was also discussed. The synthesized compounds showed promising corrosion inhibition efficiencies under the outlined test conditions. Best inhibitions were obtained at 27°C and 100 ppm concentration of corrosion inhibitors.     

Corrosion inhibition and Biocidal effect of some cationic surfactants based on Schiff base

The three cationic surfactants based on Schiff base were laboratory prepared, (E)-decyl-4-[(2-hydroxyethylamino) methyl]-N,N-dimethyl benzenaminium bromide (I), (E)-dodecyl-4-[(2-hydroxyethylamino)methyl]-N,N-dimethyl benzenaminium bromide (II) and (E)-hexadecyl-4-[(2-hydroxyethylamino)methyl]-N,N-dimethyl benzenaminium bromide (III) were evaluated as corrosion inhibitors for carbon steel in acid medium and antimicrobial agents against sulfate reducing bacteria, SRB. Three techniques were used for the corrosion inhibition evaluation, namely; weight loss, polarization and electrochemical impedance. The serial dilution method was used to evaluate the inhibiting effect of these compounds on the sulfate reducing bacteria growth. The results showed that the prepared compounds have good antimicrobial activities against the SRB as well as they have high efficiency as corrosion inhibitors for carbon steel in 1 M HCl.     

Corrosion inhibition of carbon steel in acid chloride solution using ethoxylated fatty alkyl amine surfactants

Four novel non-ionic ethoxylated fatty alkyl amine surfactants (I–IV) were synthesised and investigated as corrosion inhibitors of carbon steel in 1 M hydrochloric acid solution using gravimetric, open circuit potential and potentiostatic polarisation techniques. The percentage inhibition efficiency (η%) for each inhibitor increased with increasing concentration until the critical micelle concentration (cmc) was reached. The maximum inhibition efficiency approached 95.1% in the presence of 400 ppm of the inhibitor (IV). It was found that the adsorption of the surfactants on carbon steel followed the Langmuir adsorption isotherm. Potentiostatic polarisation data indicated that these surfactants act as mixed type inhibitors. The values of activation energy (E _a*) of carbon steel dissolution in 1 M HCl were calculated in the absence and presence of 400 ppm of each inhibitor. Finally, scanning electron microscopy (SEM) was used to examine the surface morphology of polished carbon steel surfaces and those immersed in 1 M HCl in the absence and presence of 400 ppm of inhibitor (IV).     

Effectiveness of some non ionic surfactants as corrosion inhibitors for carbon steel pipelines in oil fields

The ability of new synthesized non ionic surfactants (I and II) to protect carbon steel in acid chloride solution was investigated using potentiostatic polarization, open circuit potential, weight loss and surface tension measurements. The experimental results showed that these inhibitors revealed a very good corrosion inhibition even at low concentrations. The percentage inhibition efficiency (η%) increases by increasing the inhibitor concentration until the critical micelle concentration (cmc) is reached. It was found that, the adsorption ability of the surfactant molecules on carbon steel surface increased with the increase of the molecular size of the surfactant. Potentiostatic polarization curves indicate that the inhibitors under investigation act as mixed type. Finally, the mechanism of carbon steel dissolution in acidic medium was discussed both in absence and presence of the inhibitor molecules.