Corrosion inhibition of low carbon steel in soil solutions, using novel Schiff base inhibitors.

Abstract

The investigation of Corrosion inhibition behaviour of synthesized amino acid-based Schiff base inhibitors was carried out. Its adsorption in two types of (5%) soil solutions was studied at room temperature, using potentiodynamic polarization and gravimetric techniques. The inhibition efficiency obtained at the optimum inhibitor concentration (300ppm) was a maximum of 64% in acidic, ranging from 18.66% to 64.42%. Also, 70% maximum efficiency was recorded in the neutral electrolyte, whereas the range of 3.88% to 70.6%. Moreover, the carbon steel behaviour in 3.5% NaCl and 5, 10 and 15% soil solution were studied using the weight loss method for 1440 days and experimental data then combined with modelled data for obtaining failure predictions of structure based on an increment of concentration of soil in the electrolyte. Also, the effect of soil concentration was investigated using electrochemical studies and obtained Tafel plot, which has verified that increasing the concentration of soil in the electrolyte, makes electrolyte more corrosive. Electrochemical studies results illustrated that the inhibitors worked well in a less acidic environment in one of the soil solutions, which was relatively acidic than the other. Experimental data of potentiodynamic study also indicated that the inhibitors were more inclined to adsorb on the anodic sites of the carbon steel sample. Thus, the inhibitors can be categorized as anodic inhibitors due to suppressing more anodic reactions on the carbon steel sample. Keywords: Corrosion inhibition, Schiff base, anodic-type, electrochemical methods