Role of Organic and Eco-Friendly Inhibitors on the Corrosion Mitigation of Steel in Acidic Environments-A State-of-Art Review

Abstract

Steel has versatile application in chemical, structure and construction industries owing to its mechanical properties. However, it is susceptible to corrosion in acid environments. Thus, it requires to protect the steel from corrosion. Different types of corrosion resistance steel, coatings and inhibitors are developed to mitigate the corrosion, but, inhibitor is the best remedies to control the corrosion of steel in acid condition. Moreover, organic and green inhibitors used in acid condition for descaling, acid pickling, pipelines, boiler tubes and oil-wells. Organic inhibitors reduce the dissolution of steel in acid but, it is hazardous, expensive and needs expertise to synthesize the inhibitor. Therefore, there is utmost required to study and compile the latest research about the eco-friendly corrosion inhibitors, which showed more than 90% corrosion inhibition efficiency. In the present study, I have reviewed the state-of-arts, and compile the latest development in organic and eco-friendly corrosion inhibitor used in acid environment as well as suggested about the future scope and role of green inhibitor for sustainable society, which is economical, less hazardous and readily available from the natural sources.

Keywords: acid; boiler tube; corrosion; descaling; eco-friendly inhibitor; efficiency; pickling; steel.

Figure 1

Adsorption action of inhibitor on steel surface.

Figure 2

Schematic of a boiler [59].

Figure 3

Variation of inhibition efficiency with immersion time of UMOD for N-80 steel in 15% boiling HCl from weight loss measurements [70].

Figure 4

Micrographs of mild steel after immersion in 2 M HCl solution in the presence of 400 ppm of the inhibitor [72].

Figure 5

SEM of mild steel (a) after polishing, (b) after immersion in 1.0 mol·L⁻¹ HCl and (c) after immersion in 1.0 mol·L⁻¹ HCl + 0.04% Na-CMC [75].

Figure 6

Relationship between inhibition efficiency (IE) and BAP concentration in 1.0 M H₂SO₄ [76].

Figure 7

Dependence of the inhibition efficiency values (IE%) obtained from weight loss, polarization, impedance and EFM methods recorded for a LCS in 4.0 M H₂SO₄ solutions containing different concentrations of KI alone, AD alone and various concentrations of AD in presence of 0.0005 and 0.001 M KI [81].

Figure 8

Variation of the protection efficiency with (a) the logarithmic concentrations of the inhibitors in 1.0 M H₂SO₄ at 30 °C and (b) temperatures at concentration 5 × 10⁻⁴ M inhibitors [82].

Figure 9

Corrosion protection mechanism of Guar gum in 1 M H₂SO₄ solution [83].

Figure 10

Optical micrographs showing (a) pitting (without inhibitor) and (b) adsorbed layer by 4% EDA on carbon steel surface in 16% petroleum water [135].

Figure 11

Scanning electron micrographs for: (a) polished mild steel, (b) mild steel in 20% formic acid and (c) mild steel in 20% formic acid +100 ppm APT [139].