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Performance of cactus mucilage and brown seaweed extract as a steel corrosion inhibitor in chloride contaminated alkaline media

Eddisson Francisco Hernández (Research Center – CIIDIR-Unidad Oaxaca, Instituto Politécnico Nacional, Oaxaca, Mexico and Universidad Nacional de Ingeniería, UNI, Managua, Nicaragua)
Prisciliano Felipe de Jesus Cano-Barrita (Department of Construction Materials, Instituto Politecnico Nacional CIDIIR, Oaxaca, Mexico)
Frank Manuel León-Martínez (Research Center – CIIDIR-Unidad Oaxaca, Instituto Politécnico Nacional, Oaxaca, Mexico)
Andres Antonio Torres-Acosta (Construction Materials Laboratory, Civil Engineering College, Marist University of Queretaro, Mexico (Permanent Affiliation Mexican Transport Institute, Queretaro))

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 4 September 2017

312

Abstract

Purpose

This paper aims to present experimental results related to the performance of cactus mucilage (CM) and brown seaweed extracts (SEs) to inhibit reinforcing steel bar (rebar) corrosion in saturated calcium hydroxide alkaline solutions (pH = 12.5).

Design/methodology/approach

Electrochemical cells were prepared using CM solutions at 0.5, 1 and 1.38 per cent concentration (w/v), SE solutions at 0.5, 1, 1.38, 2 and 3 per cent concentration (w/v), sodium alginate at 1 per cent concentration (w/v) and calcium nitrite at 11.3 per cent (v/v). Each cell contained six deformed reinforcing steel bars of 9.5 mm nominal diameter. The experiments were performed at 23 ± 2°C in two stages. The first stage was aimed at stabilizing the rebar until passivation was reached. The second stage included adding NaCl in six steps from 0.5 to 16 g/L. Half-cell potential, linear polarization resistance and electrochemical impedance spectroscopy measurements were monitored during both stages.

Findings

The electrochemical test results indicated that both additions reduce the corrosion rate of rebars and pitting in an alkaline media with chloride ions (16 g/L NaCl). Electrochemical impedance spectroscopy results for rebars in natural-added solutions showed higher charge transfer resistance and double layer capacitance values, indicative of the formation of a second interface between the rebar and the electrolyte.

Research limitations/implications

The information obtained was for alkaline solutions only. Further investigation is performed using concrete as the alkaline electrolyte.

Practical implications

CM and SE may be suitable low-cost corrosion inhibitors for steel in concrete.

Social implications

The use of botanical or algae products for this application will encourage people to consider its production for this particular application. Also, the possible harvest in an environmental friendly way will diminish in the future the use of biohazards and toxic inhibitors.

Originality/value

This investigation is a continuation of a one presented in 2007, which uses only nopal mucilage. This new investigation corroborates what was concluded in the early investigation and incorporates a new natural by product, algae, as a possible corrosion inhibitor product.

Keywords

Acknowledgements

Eddisson Francisco Hernández acknowledges CONACYT, Mexico, for his Graduate scholarship to pursue his PhD studies, Universidad Marista de Querétaro for its support during his research visit in Querétaro and the PIFI program from Instituto Politécnico Nacional. Prisciliano Felipe de Jesus Cano-Barrita acknowledges Conacyt from Mexico for funding the project CB 2014, ID code 239727.

Citation

Hernández, E.F., Cano-Barrita, P.F.d.J., León-Martínez, F.M. and Torres-Acosta, A.A. (2017), "Performance of cactus mucilage and brown seaweed extract as a steel corrosion inhibitor in chloride contaminated alkaline media", Anti-Corrosion Methods and Materials, Vol. 64 No. 5, pp. 529-539. https://doi.org/10.1108/ACMM-02-2016-1646

Publisher

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Emerald Publishing Limited

Copyright © 2017, Emerald Publishing Limited

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