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Date palm leaves (DPL) was extracted using acetone (ACE), ethanol (ETH), aqueous (AE), butanol (BUT), methanol (METH), isopropanol (ISO), and ethyl acetate (EHY ACT). The extracts were characterized using Fourier-transform infrared spectroscopy (FTIR) and ultraviolet-visible (UV-vis) spectroscopy. The various solvent DPL extracts were screened for anticorrosion property against low carbon steel in 15 wt.% HCl solution at 25 °C. ACE, AE, and ETH DPL extracts are found to promote the corrosion of the low carbon steel while BUT, ISO, METH, and EHY ACT DPL extracts exhibit anticorrosion property. However, BUT DPL extract shows the best anticorrosion property with 400 ppm protecting the low carbon steel by 82%. Based on the results from the screening experiments, BUT extract was selected for a comprehensive corrosion inhibition study. Inhibition effectiveness of BUT DPL extract is found to increase with increasing concentration with 1000 ppm affording 97% protection at 25 °C. The inhibition performance increases up to 40 °C but slightly decreases as the temperature was raised to 50 °C and 60 °C. However, BUT DPL extract could afford 86% protection at 60 °C. Scanning electron microscope and atomic force spectroscopy results confirm that BUT DPL extract is indeed an effective inhibitor for X60 carbon steel in 15 wt.% HCl solution.

N1,N1-diallyl-N6,N6,N6-tripropylhexane-1,6-diaminium chloride (NDTHDC) and its polymer poly(N1,N1-diallyl-N6,N6,N6-tripropylhexane-1,6-diaminium chloride) (poly-NDTHDC) were synthesized and tested against API X60 carbon steel corrosion in 15 wt % HCl solution. Weight loss, electrochemical, and surface analysis techniques were used. Results show that poly-NDTHDC is better than NDTHDC. Moreover, 1000 mg/L NDTHDC protected the studied surface by 79.1% at 25 °C, while 100 mg/L poly-NDTHDC afforded 86.1% protection. Inhibition efficiency increases with temperature (up to 60 °C) but depreciates thereafter. NDTHDC and poly-NDTHDC perform better under the hydrodynamic condition than the static condition. TGA and FTIR results reveal that poly-NDTHDC is chemically and thermally stable.

Due to strict environmental regulations, the use of toxic chemicals as corrosion inhibitors for the oil-well acidizing is restricted. Environmentally benign Vanillin-modified chitosan (Van-Cht) is synthesized using a microwave-induced green synthetic protocol and thoroughly characterized by FTIR and NMR spectroscopy. The inhibitor has been evaluated for the first time for carbon steel in 15% HCl. The corrosion inhibition performance was assayed using weight loss and electrochemical methods complemented with the surface analysis of the corroded carbon steel samples without and with the inhibitor immersed in the corrosive medium. Results obtained showed that the Van-Cht acted by adsorption on the surface of carbon steel to inhibit corrosion and exhibited a mixed-type behavior with cathodic predominance. The adsorption of Van-Cht on the carbon steel surface obeyed the Langmuir isotherm. The excellent corrosion inhibition efficiency of > 98% observed at a concentration of 500 mg L−1. Surface analysis using SEM and FTIR-ATR measurements supported the adsorption of Van-Cht inhibitor on the carbon steel surface. The pKa analysis proved that the inhibitor Van-Cht exists mainly in the protonated form at the experimental pH. The density functional theory (DFT) analysis proved that the protonated form of the Van-Cht inhibitor behaves better compared to that of the Van and neutral Van-Cht.

Rumex vesicarius (RVE) mediated chitosan–AgNPs composite was produced in situ by using an aqueous extract of Rumex vesicarius leaves as the reducing agent to reduce Ag+ to Ag0. The synthesized composite was evaluated as a sweet (CO2) corrosion inhibitor (CI) for C1018 carbon steel (CS) in 3.5 wt% NaCl solution under static and hydrodynamic conditions. The corrosion inhibitive performance was evaluated using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), and potentiodynamic polarization (PDP) techniques, as well as scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDAX), and atomic force microscopy (AFM) on corroded C1018 CS without and with additives. The effect of concentration, immersion time, temperature, and rotation speed on the CI performance of the composite was also investigated. The corrosion inhibitive effect increased with increasing composite dosage, with the highest inhibition efficiency (IE) acquired at the maximum composite dosage of 0.3%. Beyond this concentration, the IE decline with increasing concentration. Furthermore, IE was found to increase with immersion time and decline with a temperature rise from 25 to 40 °C, with the optimum temperature of 60 °C found to accelerate corrosion without and with RVE-mediated Chi–AgNPs composite. Under high shear stress, the Chi–AgNPs composite exhibits moderate corrosion inhibition under hydrodynamic conditions. The surface analysis results validate the formation of a protective covering due to composite adsorption on the CS surface. The RVE-mediated chitosan–AgNPs composite could be recommended as a CI for C1018 CS in sweet (CO2) corrosion environments at ambient temperature.

Metallic pipelines and gathering tanks play a vital role during oil and gas exploration, production, transmission, and processing. These facilities are usually attacked by corrosion. The use of corrosion inhibitors is one of the most economical and reliable approaches to control the corrosion of oil and gas metallic facilities. This paper looks at the progress made in the development of sour corrosion inhibitors from early 1900 to date. Scientific literatures were reviewed. The review identified four classes of organic corrosion inhibitors for sour environments, namely, amine-based, imidazoline-based, polymer-based, and Gemini-surfactant-based inhibitors. The strengths and weaknesses of these inhibitors were highlighted. The review revealed that the patronage of amine-based chemistries has declined, and the current technology is based on imidazoline and quaternary salt chemistries. The existing knowledge gap and the future research direction in the area of sour corrosion inhibitors development have been highlighted.

The potential of an environmentally friendly novel synthesized and characterized isoxazolidine derivative namely 5-(4-dodecyloxy-3-methoxybenzyl)-2-methylisoxazolidine (DMBMI) as anticorrosion agent for carbon steel in 1 mol/L HCl solution was investigated using gravimetric and electrochemical techniques. Kinetics parameters of the corrosion process and the thermodynamic data of adsorption of the organic molecule on the carbon steel surface was also assessed in order to characterize the performance of the studied compound as a corrosion inhibitor. The solubility, toxicity and the state of the molecule at the acidic pH (1 mol/L HCl) was predicted. It was found that the synthesized compound is green (environmentally friendly) with an optimum solubility of 23.8 mg/L. Also the molecule exists 100 percent in protonated form in 1 mol/L HCl (pH = 0). The molecule possesses anticorrosion property against steel corrosion in acid environment. Corrosion retardation efficacy is dependent on concentration and temperature. DMBMI exhibited concentration dependent corrosion inhibition ability influencing mainly anodic metal dissolution based on potentiodynamic polarization data. Addition of KI through the mechanism of competitive adsorption enhanced the inhibition efficiency considerably. The active sites for the interaction of DMBMI with steel surface was calculated using quantum chemical method while the adsorption energy between the inhibitor and steel surface was derived via Monte Carlo simulations. Results from theoretical studies and surface analysis are in conformity and reveal that the O and N heteroatoms in the synthesized molecule are the interaction centers. Keywords: Isoxazolidine compounds, Theoretical studies, Corrosion inhibitor, Acid corrosion, Steel

Plant biomaterials as inexpensive, nontoxic, biodegradable materials are found abundantly in nature. They contain heteroatoms and/or pi electrons that make them candidate for metals corrosion inhibitor. In recent years, numerous research works have been undertaken on plant biomaterials as metals corrosion inhibitor in different corrosive media. This review critically looks at the researches done in the years 2013–2018. Corrosive environments covered include acidic, basic, neutral, aqueous, geothermal fluid and artificial saliva. The major findings and the mechanism of inhibition has been elucidated. The missing gap in this area of research has been pointed out and future direction proposed.

A novel random copolymer 4, containing diallylmethylamine and N1,N1-diallyl-N1-methyl-N6,N6,N6-tripropylhexane-1,6-diammonium dibromide units in a 1:1 ratio (polymer 4) was synthesized via Butler's cyclopolymerization technique. Characterization was accomplished by 1H NMR, elemental analysis, and Fourier-transform infrared spectroscopy (FTIR). Polymer 4 was tested as corrosion inhibitor for low carbon steel in 15% HCl solution via gravimetric and electrochemical approaches. The analysis of the metal specimen surfaces was done using scanning electron microscope (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDAX), and X-ray photoelectron spectroscopy (XPS) methods. Polymer 4 is inhibitor for the substrate particularly at elevated temperatures. Corrosion mitigation is by chemisorption mechanism and can be best described with the Langmuir and El-Awady et al. kinetic-thermodynamic adsorption isotherms. Polymer 4 corrosion mitigation capacity can be improved by the addition of a minute amount of I− ions. Inhibition efficiency of 92.99% has been achieved with 500 ppm polymer 4 + 1 mM KI mixture at 25 °C. Surface analysis results support the claim of adsorption of additive molecules on steel surface. From XPS results, corrosion products on steel surface exposed to the free acid solution are mixtures of chlorides, carbonates, oxides, and hydroxides. In polymer 4 + KI system, polymer 4 molecules are adsorbed on triiodide and pentaiodide ions layer. The improved corrosion inhibition of polymer 4 by I− ions is synergistic in nature according to calculated synergism parameter. Polymer 4 is a promising corrosion inhibitor for oil well acidizing purpose.

Corrosion defined as the deterioration of a material when it interacts with its environment is a global problem. Among the different strategies employed to combat corrosion, the use of coatings and corrosion inhibitors are the most popular. Coatings or corrosion inhibitors form a layer over the metallic substrate and protect it against corrosion. Polymers, both naturally occurring and synthetic have been tested for metal corrosion protection as replacement for the toxic inorganic and organic corrosion inhibitors. Interest in them stems from their availability, cost effectiveness, and eco-friendliness (especially for natural polymers) in addition to the inherent stability and multiple adsorption centers. However, it is found that most polymeric materials studied are moderate corrosion inhibitors. Several attempts such as copolymerization, addition of substances that exert synergistic effect, cross linking, blending, and most recently incorporation of inorganic substances in nano size into the polymer matrix have been made to improve the inhibition ability of polymers. In this review, the application of conducting polymers, polymer composites and nanocomposites for corrosion protection of different industrial metal substrates are explored based on reported experimental data and their mechanism of inhibition explained. Some identified drawbacks and future direction in this area have also been highlighted.

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...

A novel tetrapolymer (TP) consisting of carboxylate, sulphonate, phosphonate and sulfur dioxide based co-monomers was synthesized using Butler cyclopoymerization technique. The synthesized tetrapolymer was characterized using FTIR, 1H-NMR, 13C NMR and elemental analysis. The performance of the tetrapolymer as a corrosion inhibitor for St37 carbon steel in 15% HCl and 15% H2SO4 acid media was assessed using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), potentiodynamic polarization (PDP) and electrochemical frequency modulation (EFM) techniques. The influence of addition of a small amount of KI on the corrosion inhibition efficiency of TP was also assessed. Results obtained showed that the tetrapolymer moderately inhibited the corrosion of St37 steel in the acid media with protection efficiency of 79.5% and 61.1% at the optimum concentration of 1000 mg·L− 1 studied in HCl and H2SO4 media respectively. On addition of 5 mmol·L−1 KI to the optimum tetrapolymer concentration, the protection efficiency was upgraded to 90.6% and 93.5% in HCl and H2SO4 environment, respectively. The enhanced performance of the polymer in the presence of KI is due to synergistic action deduced from synergism parameter (S1) which was found to be greater than unity. The tetrapolymer afforded the corrosion inhibition of St37 steel in the acid media by virtue of adsorption of the polymer molecules on the steel surface which was confirmed by ATR-FTIR analysis of the adsorbed film extracted from the steel surface. TP + KI formed complex with St37 steel surface in H2SO4 solution but not in HCl solution.

s Investigation into amitriptyline (AMI) as a corrosion inhibitor for different grades of pipeline steels (X80, J55 and mild steel) was undertaken under static conditions in 3.7% and 15% HCl solution and temperature ranging from 30 to 90 °C using electrochemical, gravimetric, and surface screening approaches. AMI is adjudged an effective steel corrosion inhibitor in 3.7% HCl at 30 °C but poor inhibitor at high temperatures and in 15% HCl. The values of enthalpy of adsorption and variation of protection efficacy with temperature point to physical interaction between AMI molecules and the steel surface. Evidence of formation of adsorbed film on the specimen surface has been found via Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDAX) screening. Various formulations consisting of AMI as the base component and other additives (potassium iodide, glutathione and N-acetyl cysteine) have been developed. The formulations were tested at different experimental conditions and inhibition performance compared with that of a commercial corrosion inhibitor. Results obtained show that AMI based formulations can compete favorably with commercial inhibitor even at severe conditions. In 15% HCl solution and temperature of 90 °C, inhibition efficiency of 94% is recorded for commercial inhibitor and 92% for AMI based formulation. AMI based formulation can be utilized as effective corrosion inhibitor in oil and gas production.

The inhibitive efficacy of environmental friendly pyrazine derivatives, 2,3-pyrazine dicarboxylic acid (Pyrazine C), pyrazine carboxamide (Pyrazine E) and 2-methoxy-3-(1-methylpropyl) pyrazine (Pyrazine H), on X60 steel were investigated in 15% hydrochloric acid (HCl), which simulate oil well acidizing conditions. The inhibitors were examined for their inhibition performance utilizing weight loss measurement at 60 °C and 90 °C for 6 h and electrochemical methods namely potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) at 25 °C. Results showed that efficiencies of pyrazines C and E were not affected by increase in their concentrations at 60 °C, however inhibition performance of pyrazine E increased with concentration at 90 °C while pyrazine C remained unchanged. The inhibition performance of pyrazine H increased with concentration at both temperatures. It was observed that addition of sodium Iodide (NaI) and Glutathione (Glu) enhanced the inhibition performance of pyrazine C and E but has no significant effect on pyrazine H. Potentiodynamic test showed that the three pyrazine derivatives investigated are mixed typed inhibitors. Pyrazine C and H are predominantly cathodic whereas pyrazine E was shown to be predominantly anodic. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy were utilized to further confirm the inhibition of steel corrosion by the three pyrazine derivatives.

The quest to replace toxic chemicals in the nearest future is revolutionizing the corrosion inhibitor research world by turning its attention to plant biomaterials. Herein, we report the corrosion inhibiting potential of butanolic extract of date palm leaves (BUT) on the corrosion of API 5L X60 carbon steel in 15 wt.% HCl solution. The mass loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), linear polarization (LPR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), and atomic force microscopy (AFM) techniques were employed in the investigation. We also report the effect of intensifier additives, namely formic acid (FA), potassium iodide (KI), and zinc nitrate (Zn(NO3)2) as well as temperature on the corrosion inhibiting performance of BUT. BUT exhibits inhibiting ability but the extent of inhibition is dependent on concentration, temperature, and intensifiers’ concentration. At 25 °C, 200 mg/L BUT and 700 mg/L BUT protected the carbon steel surface by 50% and 88%, respectively. The addition of 3 mM FA and 5 mM KI to 200 mg/L upgraded the extract performance to 97% and 95%, respectively. Zn(NO3)2 performs poorly as an intensifier for BUT under acidizing conditions. The adsorption of BUT + FA and BUT + KI is synergistic in nature whereas that of BUT + Zn(NO3)2 drifts towards antagonistic behavior according to the calculated synergism parameter. Increase in the system temperature resulted in a slight decline in the inhibition efficiency of BUT + FA and BUT + KI but with efficiency of above 85% achieved at 60 °C. The SEM and AFM results corroborate results from the electrochemical techniques.

Corrosion is a critical problem that can be found in all industries worldwide. Corrosion is particularly serious in the petroleum industry, due to the large amounts of metallic based assets located throughout the entire supply chain. Annual costs of corrosion and its consequences are estimated to be 3 – 5 % of GDP for developed countries of the world. Corrosion mitigation strategies adopted by some industries include materials selection, coatings and linings, cathodic protection and the use of corrosion inhibitors amongst others. The use of biopolymers for corrosion protection of industrial metal substrates particularly as corrosion inhibitors has generated interest globally because they are considered as environmentally friendly in addition to the possession of multiple adsorption centres. However, it is found that most biopolymers studied function as moderate corrosion inhibitors. Some of the steps taken to offset this drawback include copolymerization, addition of substances to exert synergistic action as well as the incorporation of inorganic substances in nano-size into the biopolymer matrix in order to improve the corrosion inhibition performances of the biopolymers. The application of biopolymer composites and nanocomposites as anticorrosion materials has shown promising results and is believed to form metal chelate which could block metal surfaces from aggressive ions present in corrosive media. In this chapter, the application of composites and nanocomposites of biopolymers such as chitosan, carboxyl methylcellulose, gum Arabic, Xanthan gum for corrosion protection of industrial metal substrates in different corrosive media is discussed.

Chitosan–copper oxide (CHT–CuO) nanocomposite was made by an in-situ method utilizing olive leaf extract (OLE) as reductant. The OLE mediated CHT–CuO nanocomposite containing varying amount of chitosan (0.5, 1.0 and 2.0 g) was evaluated as corrosion inhibitor for X60 carbon steel in 5 wt% hydrochloric acid solution. The corrosion inhibitive performance was assessed utilizing weight loss and electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization techniques complemented with surface assessment of the corroded X60 carbon steel without and with the additives using scanning electron microscopy/energy dispersive X-ray spectroscopy and 3D optical profilometer. The effect of KI addition on the corrosion protection capacity of the nanocomposites was also examined. Corrosion inhibitive effect was observed to increase with increase in the nanocomposites dosage with the highest inhibition efficiency (IE) achieved at the optimum dosage of 0.5%. The order of corrosion inhibition performance followed the trend CHT1.0–CuO (90.35%) > CHT0.5–CuO (90.16%) > CHT2.0–CuO (89.52%) nanocomposite from impedance measurements. Also, IE was found to increase as the temperature was raised from 25 to 40 °C and afterwards a decline in IE was observed with further increase in temperature to 50 and 60 °C. The potentiodynamic polarization results suggest that the nanocomposites alone and in combination with KI inhibited the corrosion of X60 carbon steel by an active site blocking mechanism. Addition of KI upgrades the IE of the nanocomposites but is not attributable to synergistic influence. The lack of synergistic influence was confirmed from the computed synergism parameter (S1) which was found to be less than unity with values of 0.89, 0.74 and 0.75 for CHT0.5–CuO, CHT1.0–CuO and CHT2.0–CuO nanocomposites, respectively, at 60 °C. Furthermore, KI addition improved the IE with rise in temperature from 25 to 60 °C. Surface analysis results confirm the formation of a protective film which could be attributed to the adsorption of the nanocomposites on the carbon steel surface.

Oil well acidizing, although a stimulation process, induces the corrosion of metallic equipment and well tubing. There is, at present, a high demand for effective and less toxic high-temperature corrosion inhibitors for the acidizing process due to the failing of the existing inhibitors at high temperatures occasioned by increases in the well depths. In this study, aspartame (ASP), a commercially available natural compound, is examined as a corrosion inhibitor for T95 carbon steel in 15 wt.% HCl solution at 60, 70, 80, and 90 °C using the weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), and optical profilometry (OP) techniques. It was found that ASP possesses a corrosion inhibiting effect at the studied conditions. Inhibition efficiency increased with increases in temperature. With 2000 ppm ASP, inhibition efficiency of 86% was achieved from the weight loss method at 90 °C after 4 h of immersion. Results from the electrochemical techniques are in good agreement with the weight loss results. PDP results reveal that ASP acted as a mixed-type corrosion inhibitor under the investigated conditions. The inhibition ability of ASP is due to adsorption on the steel surface and has been confirmed by the SEM, OP, and EDX results. ASP is a promising active compound for the formulation of acidizing corrosion inhibitors.