O.K. Abiola, N.C. Oforka, E.E. Ebenso and N.M. Nwinuka
To investigate the inhibitive effect of Delonix regia extracts to reduce the corrosion rate of aluminium in acidic media. The study was a trial to find a low cost and…
Abstract
Purpose
To investigate the inhibitive effect of Delonix regia extracts to reduce the corrosion rate of aluminium in acidic media. The study was a trial to find a low cost and environmentally safe inhibitor to reduce the corrosion rate of aluminium.
Design/methodology/approach
The inhibition efficiency was evaluated using the hydrogen evolution technique at 30°C. The mechanism of adsorption inhibition and type of adsorption isotherm was characterised from trends of inhibition efficiency and kinetic data.
Findings
Delonix regia extracts inhibited the corrosion of aluminium in hydrochloric acid solutions. The inhibition efficiency increased with increasing concentration of the inhibitor but decreased with increase in exposure time. The acid extracts (hydrochloric acid seeds extract (HSE) and hydrochloric acid leaf extract (HLE)) were found to be more effective than the ethanolic extracts (ethanol seeds extract (ASE) and ethanol leaves extract (ALE)) and the inhibition followed the order: HSE (93.6 per cent) > HLE (83.5 per cent) > ASE (63.9 per cent) > ALE (60.4 per cent). The low negative values of ΔGad: −20.14 kJ mol−1 for HSE, −18.08 kJ mol−1 for HLE, −15.96 kJ mol−1 for ASE and −15.12 kJ mol−1 for ALE, as calculated from the Langmuir isotherm, indicated that the inhibitor molecules adsorbed onto aluminium by a physiosorption‐based mechanism. A first‐order type of reaction mechanism was obtained from the kinetic treatment of the H2 gas evolution data.
Research limitations/implications
Further investigations involving electrochemical studies such as polarization method should shed further light on the mechanistic aspects of the corrosion inhibition.
Originality/value
This paper provides new information on the possible application of Delonix regia as an environmentally friendly corrosion inhibitor under the specified conditions. This environmentally friendly inhibitor could find possible applications in metal surface anodizing and surface coatings.
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Mohammed Elalaoui Belghiti, Ayssar Nahlé, Abdeslam Ansari, Yasser Karzazi, S. Tighadouini, Yassir El Ouadi, A. Dafali, Belkheir Hammouti and Smaail Radi
This paper aims to study the inhibition effect of 2-pyridinealdazine on the corrosion of mild steel in an acidic medium. The inhibition effect was studied using weight loss…
Abstract
Purpose
This paper aims to study the inhibition effect of 2-pyridinealdazine on the corrosion of mild steel in an acidic medium. The inhibition effect was studied using weight loss, electrochemical impedance spectroscopy, and Tafel polarization measurements.
Design/methodology/approach
Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy, X-ray diffraction and spectral and conformational isomers analysis of A (E-PAA) and B (Z-PAA) were performed were investigated.
Findings
2-pyridinealdazine (PAA) acts as a good inhibitor for the corrosion of steel in 2.0 M H3PO4. The inhibition efficiency increases with an increase in inhibitor concentration but decreases with an increase in temperature.
Originality/value
This paper is intended to be added to the family of azines which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.
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Kathirvel Kalaiselvi, Ill-Min Chung, Seung-Hyun Kim and Mayakrishnan Prabakaran
The purpose of this paper is to investigate the inhibitive performance of Coreopsis tinctoria (C. tinctoria) plant extract for the corrosion of mild steel in 0.5 M H2SO4.
Abstract
Purpose
The purpose of this paper is to investigate the inhibitive performance of Coreopsis tinctoria (C. tinctoria) plant extract for the corrosion of mild steel in 0.5 M H2SO4.
Design/methodology/approach
The inhibition efficiency was studied by weight loss, electrochemical measurements and the surface analysis was done by Raman, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS) and atomic absorption spectroscopy (AAS) analysis.
Findings
Maximum inhibition efficiency of C. tinctoria in 0.5 M H2SO4 on mild steel is 80.62 per cent (500 ppm) at 303 ± 1K. The adsorption of the C. tinctoria on the mild steel surface in 0.5 M H2SO4 was found to obey Langmuir adsorption isotherm. Temperature studies were carried out and the significant parameters, such as change in enthalpy (ΔH°), change in entropy (ΔS°) and change in free energy (ΔG°ads) and heat of adsorption (Qads), were calculated. The productive layer formed on the mild steel surface in 0.5 M H2SO4 were confirmed by the Raman spectral analysis.
Originality/value
This paper provides information on the inhibitive properties of C. tinctoria plant extract which is found to be a good corrosion inhibitor for mild steel in 0.5 M H2SO4.
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Asmae Bouoidina, Mehdi Chaouch, Abdelfattah Abdellaoui, Amal Lahkimi, Belkheir Hammouti, Fadoua El-Hajjaji, Mustapha Taleb and Ayssar Nahle
The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance…
Abstract
Purpose
The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance spectroscopy and Tafel polarization, as well as the surface morphology of the mild steel.
Design/methodology/approach
Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy studies and gas chromatography/mass spectrometry and scanning electron microscopy analysis of FVS extract were performed.
Findings
FVS extract acts as a good inhibitor for the corrosion of mild steel in 1.0 M HCl. The inhibition efficiency increases with the increase in inhibitor concentration but decreases with the increase of temperature.
Practical implications
FVS extract was observed to play an important role in the corrosion inhibition of mild steel in acidic solution.
Originality/value
This paper is intended to be added to the family of green inhibitors which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.
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N.O. Eddy and E.E. Ebenso
The purpose of this paper is to study the inhibitive and adsorptive characteristics of ethanol extract of Gongronema latifolium (GL) as a corrosion inhibitor for mild steel in H2SO…
Abstract
Purpose
The purpose of this paper is to study the inhibitive and adsorptive characteristics of ethanol extract of Gongronema latifolium (GL) as a corrosion inhibitor for mild steel in H2SO4.
Design/methodology/approach
The inhibition efficiencies were evaluated using thermometric and hydrogen evolution techniques.
Findings
The inhibition efficiency of ethanol extract of GL vary with concentration of the extract, period of immersion and with temperature. The extract acts as an inhibitor because of its phytochemical and amino acid composition. The extract is adsorbed spontaneously on the surface of mild steel according to Langmuir adsorption isotherm. The mechanism of physical adsorption is proposed from the trend of the inhibition efficiency with temperature and the values of some kinetic and thermodynamic parameters obtained.
Research limitations/implications
The study provides information on the use of ethanol extract of GL as a corrosion inhibitor. Electrochemical studies such as polarisation and alternating current impedance spectra will throw more light on the mechanistic aspects of the corrosion inhibition.
Practical implications
Ethanol extract of GL can be used as an environmentally friendly inhibitor for the corrosion of mild steel in H2SO4.
Originality/value
This environmentally friendly inhibitor could find possible applications in metal surface anodising and surface coatings.
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The aim of this paper is to appraise the inhibiting potential of hydroxypropyl methylcellulose (HPMC) on the corrosion of mild steel and aluminium in sulphuric and hydrochloric…
Abstract
Purpose
The aim of this paper is to appraise the inhibiting potential of hydroxypropyl methylcellulose (HPMC) on the corrosion of mild steel and aluminium in sulphuric and hydrochloric acid solutions.
Design/methodology/approach
The effects of two different corrodents on the dissolution of mild steel and aluminium were examined. Corrosion rates were determined using the weight loss technique. Inhibition efficiency was estimated by comparing the corrosion rates in absence and presence of the additive. The kinetics and mechanism of HPMC adsorption were investigated by impedance study while the anodic and cathodic partial reactions were studied by polarization measurements.
Findings
The results reveal that corrosion rate of mild steel and aluminium decreased with addition of HPMC. The corrosion rate and inhibition efficiency were found to depend on the concentration of the inhibitor. The polarization data indicated that the inhibitor was of mixed-type, with predominant effect on the cathodic partial reaction. electrochemical impedance spectroscopy confirms that corrosion inhibition was by adsorption on the metal surface following Freundlich adsorption isotherm via physisorption mechanism.
Originality/value
Hydroxypropyl methylcellulose has been studied for the first time as an inhibitor of mild steel and aluminium corrosion and the results suggest that the inhibitor could find practical applications in corrosion control in HCl and H2SO4 acid media. The findings are particularly useful, considering the fact that HPMC is a good film former and viscosity enhancer which could also be used in paint formulation.
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The purpose of this paper is to study the inhibitive and adsorptive characteristics of ethanol extract of Heinsia crinata for the corrosion of mild steel in H2SO4 solutions.
Abstract
Purpose
The purpose of this paper is to study the inhibitive and adsorptive characteristics of ethanol extract of Heinsia crinata for the corrosion of mild steel in H2SO4 solutions.
Design/methodology/approach
The inhibition efficiencies were evaluated using weight loss, thermometric and hydrogen evolution techniques while adsorption properties were studied using IR spectroscopy.
Findings
The inhibition efficiency of ethanol extract of Heinsia crinata varies with concentration of the extract, period of immersion and with temperature. The extract acts as an adsorption inhibitor because of its phytochemical composition. The extract is adsorbed spontaneously on the surface of mild steel according to Temkin and Frumkin adsorption isotherms. The mechanism of physical adsorption is proposed from the trend of the inhibition efficiency with temperature and the values of some kinetic and thermodynamic parameters obtained.
Research limitations/implications
The paper provides information on the use of ethanol extract of Heinsia crinata as a corrosion inhibitor. Electrochemical studies such as polarisation and AC impedance spectra will throw more light on the mechanistic aspects of the corrosion inhibition.
Practical implications
Ethanol extract of Heinsia crinata can be used as an environmentally friendly inhibitor for the corrosion of mild steel in H2SO4. This environmentally friendly inhibitor could find possible applications in metal surface anodising and surface coatings.
Originality/value
The paper provides information on an environmentally‐friendly corrosion inhibitor.
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Chinyere Elizabeth Agiriga, Emeka Oguzie, Arinzechukwu Chidiebere, Nnaemeka John Okorocha and Reginald Ndubuisi Chikwe
This paper aims to investigate the corrosion inhibition efficiency of Landolphia heudelotii (LH) on mild steel in 1 M HCl and 0.5 M H2SO4 using weight loss and potentiodynamic…
Abstract
Purpose
This paper aims to investigate the corrosion inhibition efficiency of Landolphia heudelotii (LH) on mild steel in 1 M HCl and 0.5 M H2SO4 using weight loss and potentiodynamic polarization techniques.
Design/methodology/approach
Water extract of LH was used as corrosion inhibitor on mild steel in acidic media at room temperature and elevated temperatures (30-60°C). Various concentrations of the plant extract were prepared from the stock solution obtained after solvent extraction. The inhibition efficiency of LH extract was evaluated and mechanism of adsorption was deduced.
Findings
LH extract showed significant corrosion inhibition on mild steel in both acidic media, with inhibition efficiency increasing with extract concentration. Potentiodynamic polarization measurements revealed mixed inhibition mechanism. Optimum inhibition efficiency was recorded at 2500 mg/L after 288 h. Mechanism of adsorption was mainly of physisorption. The inhibitor exhibited good inhibition efficiency even at elevated temperature.
Research limitations/implications
This study provides new data on the anticorrosion characteristics of LH extract under the specified conditions. Further studies could expand the experimental variables and use advanced surface probe techniques.
Practical implications
The developed inhibitor provides an alternative method of inhibiting corrosion on mild steel using eco-friendly materials from natural products which are less toxic, safer, cost-effective and readily available.
Originality/value
The method used was effective and the inhibitor developed can be incorporated in surface coatings where mild steel is used as construction materials, as tube sheets, rods and bars.
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Shabnam Ashhari and Ali Asghar Sarabi
– This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde and 2-methylindole on mild steel in 1 M HCl solution.
Abstract
Purpose
This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde and 2-methylindole on mild steel in 1 M HCl solution.
Design/methodology/approach
Indole-3-carbaldehyde and 2-methylindole as corrosion inhibitors of mild steel in 1 M HCl solution were investigated by polarisation and electrochemical impedance spectroscopy (EIS). Adsorption isotherm and mechanism were calculated. Quantum chemical calculations were used to find out a correlation between electronic structure of inhibitors and inhibition efficiency. Changes in the properties of metal surface in HCl solution in the presence of inhibitors were studied by contact angle measurements.
Findings
Polarisation results revealed inhibitors could reduce cathodic and anodic reactions rates on metal surface. EIS analysis showed that inhibition efficiency of indoles increases by increasing the inhibitors’ concentration; maximum inhibition efficiency was 95 and 94 per cent in solutions containing 1 mM indole-3-carbaldehyde and 2-methylindole, respectively. Inhibitors’ adsorptions on metal surface were confirmed by analysing the exposed metals’ surface through contact angles measurements. The adsorption of inhibitors was found to follow Langmuir isotherm. Quantum chemical calculations showed that a more positively charged benzene ring in the structure of two indole-based inhibitors would lead to higher adsorption to metal.
Originality/value
This research was carried out to understand the effects of two different functional groups (-C=O, -CH3) with different induction effects on the indole structure and on inhibition efficiency of corrosion inhibitors with the purpose of using these components in industrial application as acid wash solutions to etch and remove rusts from metal surfaces.
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Chigoziri N. Njoku, Temple Uzoma Maduoma, Wilfred Emori, Rita Emmanuel Odey, Beshel M. Unimke, Emmanuel Yakubu, Cyril C. Anorondu, Daniel I. Udunwa, Onyinyechi C. Njoku and Kechinyere B. Oyoh
Corrosion is a major concern for many industries that use metals as structural or functional materials, and the use of corrosion inhibitors is a widely accepted strategy to…
Abstract
Purpose
Corrosion is a major concern for many industries that use metals as structural or functional materials, and the use of corrosion inhibitors is a widely accepted strategy to protect metals from deterioration in corrosive environments. Moreover, the toxic nature, non-biodegradability and price of most conventional corrosion inhibitors have encouraged the application of greener and more sustainable options, with natural and synthetic drugs being major actors. Hence, this paper aims to stress the capability of natural and synthetic drugs as manageable and sustainable, environmentally friendly solutions to the problem of metal corrosion.
Design/methodology/approach
In this review, the recent developments in the use of natural and synthetic drugs as corrosion inhibitors are explored in detail to highlight the key advancements and drawbacks towards the advantageous utilization of drugs as corrosion inhibitors.
Findings
Corrosion is a critical issue in numerous modern applications, and conventional strategies of corrosion inhibition include the use of toxic and environmentally harmful chemicals. As greener alternatives, natural compounds like plant extracts, essential oils and biopolymers, as well as synthetic drugs, are highlighted in this review. In addition, the advantages and disadvantages of these compounds, as well as their effectiveness in preventing corrosion, are discussed in the review.
Originality/value
This survey stresses on the most recent abilities of natural and synthetic drugs as viable and sustainable, environmentally friendly solutions to the problem of metal corrosion, thus expanding the general knowledge of green corrosion inhibitors.