Inhibitive effect of methyl green dye on the corrosion of low carbon steel in acidic media

Abstract

Purpose

The purpose of this paper is to study methyl green dye (MG) as a corrosion inhibitor for low carbon steel (LCS) in hydrochloric acid (1 M) and sulphuric acid (0.5 M) and to assess the effect of temperature variation and halide additives on the inhibition efficiency.

Design/methodology/approach

Corrosion rates are monitored using the gravimetric technique. Inhibition efficiency is determined by comparing the corrosion rates in the absence and presence of additives. Attempts are also made to elucidate the inhibition mechanism from the trend of inhibition efficiency with change in temperature and type of acid anion.

Findings

MG reduces the corrosion rate of the LCS specimens in both acid media within the investigated temperature range by adsorption at the metal/solution interface. Inhibition efficiency increases with MG concentration but decreases with rise in temperature. Maximum values of 67 and 73 per cent are obtained in 1 M HCl and 0.5 M H₂SO₄, respectively, at [MG]=0.001 mol dm⁻³. Halide additives increase the inhibition efficiency mainly in the sulphuric acid medium.

Research limitations/implications

The inhibiting effect of MG is studied within a fixed concentration range, which can be expanded for further studies. The same applies to the effect of halide additives. Also, the dye structure can be modified by introducing different functional groups, and the effect on inhibition efficiency is investigated.

Practical implications

The research findings can find practical application for corrosion control in aqueous acidic environments.

Originality/value

This paper provides new information on the application of MG for corrosion inhibiting purposes. The experimental results form part of an extensive database on the corrosion inhibiting characteristics of organic dyes.

Citation

Oguzie, E., Akalezi, C. and Enenebeaku, C. (2009), "Inhibitive effect of methyl green dye on the corrosion of low carbon steel in acidic media", Pigment & Resin Technology, Vol. 38 No. 6, pp. 359-365. https://doi.org/10.1108/03699420911000600