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1 – 10 of 78S. El Issami, L. Bazzi, M. Mihit, B. Hammouti, S. Kertit, E. Ait Addi and R. Salghi
To correlate the inhibitory effect of triazole compounds on the corrosion of copper in HCl at various temperatures by semi‐empirical molecular orbital theory.
Abstract
Purpose
To correlate the inhibitory effect of triazole compounds on the corrosion of copper in HCl at various temperatures by semi‐empirical molecular orbital theory.
Design/methodology/approach
Two triazoles were selected as the best inhibitors among the triazole compounds tested. Gravimetric and electrochemical measurements were conducted.
Findings
Correlation between inhibition efficiency and calculation of molecular orbital of triazole compounds was obtained. Cu(I)‐triazole complex formation was confirmed by UV spectroscopy.
Research limitations/implications
The calculation of energetic levels of molecular orbital may be a tool to explain the classification of inhibitor efficiency.
Practical implications
The theoretical calculation is a complementary mean to selecting an efficient inhibitor among a given series. Good agreement between the experimental methods explored and theoretical calculations was observed.
Originality/value
The originality of this work was the finding of the correlation between energetic levels of orbital molecular and inhibitor efficiency of triazole compounds. The confirmation of the formation of Cu(I)‐triazole by UV‐visible spectroscopy was also new.
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M. Mihit, R. Salghi, S. El Issami, L. Bazzi, B. Hammouti, El. Ait Addi and S. Kertit
To evaluate the effect of some tetrazole compounds as corrosion inhibitors of copper in HNO3 at various temperatures.
Abstract
Purpose
To evaluate the effect of some tetrazole compounds as corrosion inhibitors of copper in HNO3 at various temperatures.
Design/methodology/approach
1‐phenyl‐5‐mercapto‐1,2,3,4‐tetrazole (PMT) was selected as the best inhibitor among the tetrazole compounds tested. Gravimetric and electrochemical techniques were conducted.
Findings
PMT was an excellent inhibitor for copper in acid. Its efficiency attained 97.5 per cent and decreased slightly with temperature.
Research limitations/implications
The inhibition efficiency increased with the concentration of PMT to reach 97.5 per cent at 10−3 M. Good agreement between the various methods explored was observed. Polarisation measurements also showed that PMT acted as a mixed inhibitor.
Practical implications
The efficiency of PMT increased with the concentration but decreased with rise of temperature in the 298‐333 K range. As such, PMT could be used in chemical cleaning and pickling processes.
Originality/value
The originality of this work was the finding of an efficient inhibitor (PMT) having a nearly 100 per cent efficiency.
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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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Sihem Kherraf, Emna Zouaoui and Mohamed Salah Medjram
The purpose of this study was to investigate the inhibitive action of some green leaves on Monel 400 alloy in acidic media.
Abstract
Purpose
The purpose of this study was to investigate the inhibitive action of some green leaves on Monel 400 alloy in acidic media.
Design/methodology/approach
Green leaves of Mespilus japonica, Ricinus communis L and Vitis vinifera were immersed in methanol solutions, separately, and filtrated after 48 h of immersion; the obtained filtrates were examined as corrosion inhibitors of Monel 400 alloy in hydrochloric acid solution (1.0M HCl). The performance of these inhibitors was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization. The effect of temperature on corrosion behavior of Monel 400 was also studied.
Findings
The results obtained showed that all tested inhibitors performed as good corrosion inhibitors. The inhibition process is attributed to the adsorption of the inhibitors on Monel surface. The adsorption behavior was found to follow Langmiur isotherm. The inhibition efficiencies of extracts increased with increasing the concentration of each inhibitor and deceased with increasing the temperature.
Practical implication These inhibitors could have application in industries where hydrochloric solutions were used to remove the surface impurities of Monel 400.
Originality/value
This paper helps to find new corrosion inhibitors that are safe and eco-friendly.
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Ediomo-Ubong Nelson and Tasha Ramirez
Current responses to women's violence are rooted in stereotypical views that delink women's violence from the context of gendered inequality and social marginalisation that…
Abstract
Current responses to women's violence are rooted in stereotypical views that delink women's violence from the context of gendered inequality and social marginalisation that mediates it. In this chapter, we draw from feminist scholarship on women's violence, including violence by female sex workers (FSWs), and qualitative data to examine different forms of FSWs' violence against their male clients and the contexts that shape their use of violence. Twenty-seven in-depth interviews were conducted with FSWs recruited through snowball sampling in Uyo, Nigeria. Thematic analysis revealed three forms of violence: ‘situational violence’ – an individual-centred, self-defensive and spontaneous response to conflict situations; ‘collective violence’ – pre-meditated violence used by a group of FSWs to revenge the victimisation of its member, and ‘symbolic violence’ – the un-planned outcome of FSWs' violence that has the effect of deterring client violence and inducing cooperative behaviour. FSWs use violence to deter or counter threatened or enacted client violence and to exact revenge for past victimisation. They also use violence to enforce rules, extract payments and establish solidarity. FSWs' violence is contextualised within the everyday experience of client violence. This violence is not only reactionary; it is a pragmatic attempt to negotiate structural and gender dynamics that shape risks in sex work.
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A.N. Önal and A.A. Aksüt
The effect of tolyltriazole (TTA) on the corrosion of Al‐Cu, Al‐Si‐Cu and Al‐Cu‐Fe alloys in HCl (pH = 0.5) and NaCl (pH = 6 and 11) respectively at 15○C, 25○C and 35○C has been…
Abstract
The effect of tolyltriazole (TTA) on the corrosion of Al‐Cu, Al‐Si‐Cu and Al‐Cu‐Fe alloys in HCl (pH = 0.5) and NaCl (pH = 6 and 11) respectively at 15○C, 25○C and 35○C has been studied by electrochemical methods. Corrosion potentials, corrosion rates, polarization resistances, inhibition efficiencies and activation energies have been determined. The results have shown that the inhibition efficiencies of TTA changed with pH and temperature. TTA has been adsorbed on the alloys to form Cu(I)‐TTA film. TTA was more efficient at pH = 0.5 and 6 than at pH = 11. Increasing the temperature from 15○C to 35○C decreased the inhibition effect of TTA.
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Khaoula Nasr, Michele Fedel, Khaled Essalah, Flavio Deflorian and Nebil Souissi
This study aims to investigate the inhibition performance of an aqueous extract of Matricaria recutita chamomile on the corrosion of S235JR steel in 0.5 M NaCl by using…
Abstract
Purpose
This study aims to investigate the inhibition performance of an aqueous extract of Matricaria recutita chamomile on the corrosion of S235JR steel in 0.5 M NaCl by using electrochemical impedance spectroscopy (EIS) and polarization measurements.
Design/methodology/approach
The inhibition performance was investigated using EIS and polarization measurements. Surface analysis demonstrates the presence of a protective layer on the steel surface in the presence of the extract. Quantum chemical parameters calculated for the molecules contained in the aqueous extract are interpreted to predict the corrosion inhibition efficiency of the considered extract.
Findings
The inhibition efficiency of chamomile aqueous extract for S235JR steel increases with increasing amounts of plant concentration and with an increase in the immersion time. The optimal inhibition efficiency of chamomile extract, 98.90 per cent, was achieved for S235JR steel when immersed in 15 per cent v/v of extract concentration for 2 h. The surface analysis in the absence and presence of the chamomile extract confirmed the formation of a protective layer on steel surface. The quantum chemical calculations allowed to explain the great inhibition efficiency values by interpreting the calculated quantum parameters.
Originality/value
This is the first study carrying out an experimental and theoretical investigation on M. recutita chamomile as a green corrosion inhibitor, with interesting potential industrial applications.
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Walid Belmaghraoui, Aimad Mazkour, Hicham Harhar, Mourad Harir and Souad El Hajjaji
This study aims to investigate the corrosion inhibition effect of extracted oil from Ziziphus lotus fruit on corrosion of C38 carbon steel in 5.5 M H3PO4 solution using…
Abstract
Purpose
This study aims to investigate the corrosion inhibition effect of extracted oil from Ziziphus lotus fruit on corrosion of C38 carbon steel in 5.5 M H3PO4 solution using potentiodynamic polarization and impedance techniques.
Design/methodology/approach
Oil composition was determined using gas chromatography, and the results showed that oleic and palmitic acids present approximately 84.0 per cent of its total chemical content. Electrochemical impedance spectroscopy (EIS) data were analyzed by adapting it to a well-developed electric circuit model. The inhibition efficiency of Z. lotus oil was calculated and compared using Tafel polarization and EIS.
Findings
Accordingly, the oil extract was found to act as an anodic type inhibitor. Furthermore, inhibition efficiency of Z. lotus oil extract increase with oil concentrations and achieve approximately 70.5 per cent at 3 g/L solution of Z. lotus oil.
Originality/value
The results obtained from different tested methods were in line, and the oil was able to reduce significantly the kinetics of the corrosion process of C38 carbon steel.
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Abstract
The effects of the addition of poly(4‐vinylpyridine) (P4VP) and its derivative poly(4‐vinylpyridine poly‐3‐oxide ethylene) (P4VPPOE) on the corrosion of Cu60‐Zn40 in 0.5M HNO3 have been investigated by potentiodynamic and weight loss measurements. Both of the studied polymers decrease the corrosion rate. Their inhibition efficiency (E%) increases with the concentration. The maximum of inhibition was obtained for P4VPPOE (100 per cent at 10–5M). E% obtained from cathodic Tafel plots and weight loss methods were in good agreement. The inhibitors were adsorbed on the Cu60‐Zn40 surface according to the Frumkin adsorption isotherm model. P4VPPOE acts as a cathodic inhibitor and its efficiency is temperature independent.
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Lin Liu, Hongyu Su, Jinjuan Xing, Dan Peng, Qiang Zhang and Jianhua Qian
This paper aims to evaluate the inhibitive effect and adsorption behavior of 5-(ethylthio)-1H-tetrazole (EHT) and 5-(benzylthio)-1H-tetrazole (BHT) on copper in a sulfur-ethanol…
Abstract
Purpose
This paper aims to evaluate the inhibitive effect and adsorption behavior of 5-(ethylthio)-1H-tetrazole (EHT) and 5-(benzylthio)-1H-tetrazole (BHT) on copper in a sulfur-ethanol system.
Design Methodology Approach
Evaluation was carried out using electrochemical measurement and surface analysis techniques. Measurements of static friction coefficient by scanning electron microscopy and contact angle analysis were applied and finally confirmed the existence of the adsorbed film. The inhibitive mechanism of the two compounds was evaluated by means of quantitative calculation and molecular dynamics simulation. The friction coefficient of corrosion surface before and after adding corrosion inhibitor was determined through static friction coefficient measurements.
Findings
The electrochemical measurement indicated that the most effective concentration of two corrosion inhibitors was 70 mg L–1, while the inhibition efficiency of that was EHT > BHT. The friction coefficient data showed that the addition of corrosion inhibitor reduced the roughness of the corrosion surface. Adsorption behavior of two inhibitors followed the Langmuir’s adsorption isotherm and was attributed to mixed-type adsorption. The results of quantitative calculation and molecular dynamics simulation showed that tetrazole rings of the two inhibitors and its connected S atoms were adsorbed on Cu(111) surface in parallel.
Originality Value
The corrosion inhibition performance of two tetrazolium derivatives in a sulfur-ethanol system was studied by combining experiments with theory, which provided a theoretical basis for the future research.
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