Effectiveness of corrosion inhibitors in saturated calcium hydroxide solutions acidified by acid rain components

Tommaselli, M. A. G.; Mariano, Neide Aparecida; Kuri, S.E.

doi:10.1016/j.conbuildmat.2007.12.002

Cited by 65 publications

(34 citation statements)

References 16 publications

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“…However, aggressive acidifying agents of the environment lower pH in concrete, thereby breaking the passive oxide layer, and render concrete steel-rebar susceptible to corrosion degradation. Acidifying agents of the environment include sulphuric acid from acid rain and wastewater in industrial environments [3,[7][8][9] and from sulphur reducing microbial activities in sewage environments [10][11][12]. Acidic sulphate from these sources attacks concrete, forms volume expansive products and an electrochemical cell of corroding steel-reinforcement that could eventually culminate, if unchecked, in the collapse of the steel-reinforced concrete structure [3,5,11].…”

Section: Introductionmentioning

confidence: 99%

“…Acidic sulphate from these sources attacks concrete, forms volume expansive products and an electrochemical cell of corroding steel-reinforcement that could eventually culminate, if unchecked, in the collapse of the steel-reinforced concrete structure [3,5,11]. In many studies, the use of corrosion inhibitors as admixtures in concrete has been identified as an easy and effective technique for mitigating corrosion degradation of steel reinforced concrete in acidic sulphate environment [4,[8][9]13]. However, the chromate and nitrite based compounds that had been found as effective inhibitors of steel-rebar corrosion in these studies suffer the setbacks of limitation and restriction on the usage of the substances due to their toxicity and environmental hazardousness [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical Performance of Phyllanthus Muellerianus on the Corrosion of Concrete Steel-reinforcement in Industrial/Microbial Simulating-environment

Okeniyi¹,

Loto²,

Popoola³

2014

Port. Electrochim. Acta

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Electrochemical monitoring techniques were employed in this study to assess anticorrosion performance of Phyllanthus muellerianus leaf-extract on concrete steelreinforcement in 0.5 M H 2 SO 4 , used for simulating industrial/microbial environment. For this, steel-reinforced concretes admixed with different concentrations of the natural plant leaf-extract were partially immersed in the acidic test-solution and subjected to electrochemical monitoring of corrosion potential, corrosion current and corrosion rate. Test responses analysed as per ASTM G16-95 R04, showed that the corrosion rate correlated, r = 84.93%, ANOVA p-value = 0.0403, with the leaf-extract concentration admixed in concrete and the ratio of the standard deviation of potential to the standard deviation of current. These identified the 0.3333% Phyllanthus muellerianus (per weight of cement) with optimum effectiveness at inhibiting steel-reinforcement corrosion both by the experimental model, η = 91.66±2.51%, and by the prediction from the correlation fitting model, η = 85.54±14.44%. Fittings of both the experimental and the predicted data followed the Flory-Huggins and the Frumkin adsorption isotherms which suggest prevalent mechanism of physical adsorption (physisorption) of the extract on steel-rebar surface. These support the use of Phyllanthus muellerianus as environmentally-friendly admixture for inhibiting concrete steel-reinforcement corrosion in the industrial/microbial service-environment.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrochemical Performance of Phyllanthus Muellerianus on the Corrosion of Concrete Steel-reinforcement in Industrial/Microbial Simulating-environment

Okeniyi¹,

Loto²,

Popoola³

2014

Port. Electrochim. Acta

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“…33 Tommaselli et al showed that sodium molybdate was more effective than sodium nitrite at low concentrations (0.013 wt%) in corrosion inhibition for carbon steel in pH 8 solution. 34 Deyab and El-Rehim showed that molybdate is better than nitrite but not as good as tungstate (which is more costly than molybdate) in inhibiting pitting corrosion in a pH 10 solution. 35 As the existing literature on corrosion inhibition by molybdate for carbon steel under alkaline conditions focuses mostly on the inhibition of localized corrosion, there is a gap regarding its effect on passivation.…”

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confidence: 99%

Effect of Molybdate on the Passivation of Carbon Steel in Alkaline Solutions under Open-Circuit Conditions

Tan¹,

Wijesinghe

Blackwood

2016

J. Electrochem. Soc.

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The effect of molybdate on the passivation of AISI 1020 carbon steel under open-circuit conditions in pH 12.5 calcium hydroxide solutions containing chloride was investigated via electrochemical tests and surface characterization techniques. In the early stage, molybdate increased the rate of passivation, with inhibition efficiency being positive. During the later stage, after the carbon steel has passivated, precipitation of calcium molybdate over parts of the sample surface resulted in slight negative inhibition efficiency and the passive film was found to have a higher proportion of ferrous cations and a smaller thickness. However, the precipitation of a thick calcium molybdate film over the entire surface can reverse this situation, increasing the polarization resistance through a cathodic inhibition mechanism. The electrochemical and XPS results showed that regardless of its effect on the final polarization resistance, the presence of calcium molybdate precipitates led to a decrease in the total extent of carbon steel oxidation, indicating an overall beneficial effect. Molybdate was also shown to be effective against localized corrosion, with 14.6 mM molybdate sufficient in preventing passivity breakdown in pH 12.5 solution containing 564 mM chloride. Carbon steel is not a corrosion resistant alloy. However, in highly alkaline environments such as concrete, the formation of a passive oxide film on the surface reduces the corrosion rate to a very low level. 1In such environments, corrosion of carbon steel occurs mostly through two mechanisms: chloride contamination and carbonation by atmospheric CO 2 resulting in a pH drop.2-10 To counter the corrosion of carbon steel in highly alkaline environments, corrosion inhibitors can be added. Currently, calcium nitrite is being used in the construction industry as an admixed inhibitor for its set-accelerating and corrosion inhibition properties. 11Considerable research has been conducted on the inhibition of carbon steel corrosion in alkaline solutions by nitrite anions. 8,[12][13][14][15][16][17][18][19] Nitrite, being an oxidizing anodic inhibitor, oxidizes ferrous cations to ferric cations rapidly at anodic sites, which then precipitate out as ferric oxyhydroxides to repair defects in the passive film.11 Calcium nitrite works well for concrete with water to cement ratio less than 0.5 and the critical [ Despite its commercial use, concerns have been raised regarding the toxicity of calcium nitrite. 20,21 The oxidizing nature of nitrite that is essential for its corrosion inhibition effect leads to methemoglobin in humans, which is a reduction in the ability of red blood cells to transport oxygen due to Fe 2+ in hemoglobin being oxidized to Fe 3+ . This negative aspect of calcium nitrite is reflected in its being banned from use in immersed reinforced concrete structures due to toxicity and solubility issues.22 Therefore, despite calcium nitrite's commercial success as a concrete rebar inhibitor, there is an ongoing search for an alternative inhibitor for carbon st...

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“…The high effectiveness of NaNO 2 at inhibiting reinforcing-steel corrosion in diverse environments has made it suitable for use in comparative study on other corrosion inhibiting prospects for carbon steel/steel in concrete, especially substances that could exhibit better environmental compatibility [27,[45][46][47]. Cymbopogon citratus (C. citratus) Poaceae, or lemongrass, is an essential-oil yielding, perennial plant used for beverage and medicinal purposes, in parts of the world, due to its antioxidant, antimicrobial, anti-inflammatory, anticarcinogenic, antihypertensive, and many other healthy/beneficial bioactive effects [48,49].…”

Section: Introductionmentioning

confidence: 99%

Cymbopogon citratusand NaNO₂Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete

Okeniyi

Popoola

Okeniyi

2018

International Journal of Corrosion

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This paper studies behaviours of Cymbopogon citratus leaf-extract and NaNO 2 , used as equal-mass admixture models, in 3.5% NaCl-immersed steel-reinforced concrete by nondestructive electrochemical methods and by compressive-strength improvement/reduction effects. Corrosion-rate, corrosion-current, and corrosion-potential constitute electrochemical test-techniques while compressive-strength effect investigations followed ASTM C29 and ASTM C33, in experiments using positive-controls for the electrochemical and compressive-strength studies. Analyses of the different electrochemical test-results mostly portrayed agreements on reinforcing-steel anticorrosion effects by the concentrations of natural plant and of chemical admixtures in the saline/marine simulating-environment and in the distilled H 2 O (electrochemical positive control) of steel-reinforced concrete immersions. These indicated that little amount (0.0833% cement for concrete-mixing) of Cymbopogon citratus leaf-extract was required for optimal inhibition efficiency, = 99.35%, on reinforcing-steel corrosion, in the study. Results of compressive-strength change factor also indicated that the 0.0833% Cymbopogon citratus concentration outperformed NaNO 2 admixture concentrations also in compressive-strength improvement effects on the NaCl-immersed steel-reinforced concrete. These established implications, from the study, on the suitability of the eco-friendly Cymbopogon citratus leaf-extract for replacing the also highly effective NaNO 2 inhibitor of steel-in-concrete corrosion in concrete designed for the saline/marine service-environment.

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Effectiveness of corrosion inhibitors in saturated calcium hydroxide solutions acidified by acid rain components

Cited by 65 publications

References 16 publications

Electrochemical Performance of Phyllanthus Muellerianus on the Corrosion of Concrete Steel-reinforcement in Industrial/Microbial Simulating-environment

Electrochemical Performance of Phyllanthus Muellerianus on the Corrosion of Concrete Steel-reinforcement in Industrial/Microbial Simulating-environment

Effect of Molybdate on the Passivation of Carbon Steel in Alkaline Solutions under Open-Circuit Conditions

Cymbopogon citratusand NaNO₂Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete

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Effectiveness of corrosion inhibitors in saturated calcium hydroxide solutions acidified by acid rain components

Cited by 65 publications

References 16 publications

Electrochemical Performance of Phyllanthus Muellerianus on the Corrosion of Concrete Steel-reinforcement in Industrial/Microbial Simulating-environment

Electrochemical Performance of Phyllanthus Muellerianus on the Corrosion of Concrete Steel-reinforcement in Industrial/Microbial Simulating-environment

Effect of Molybdate on the Passivation of Carbon Steel in Alkaline Solutions under Open-Circuit Conditions

Cymbopogon citratusand NaNO2Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete

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Cymbopogon citratusand NaNO₂Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete