Ghars date extract/iodide ions system as an eco‐friendly corrosion inhibitor for API 5L X70 steel in sulfuric acid

Abstract

BackgroundGhars date fruit is very rich in polysaccharides, which qualifies it to be exploited as a green corrosion inhibitor. Ghars date is produced in large commercial quantities in Africa and Asia, which gives them the opportunity to be used as a cheap raw material for the industry of eco‐friendly inhibitors.ObjectivesThe synergy between the Ghars date extract (GDE) and iodide ions is investigated for the first time to improve the inhibition efficiency for API 5 L X70 pipeline steel in 0.5 mol L−1 sulfuric acid.MethodsThe synergistic effect of the GDE and iodide ions is studied by potentiodynamic polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy and energy‐dispersive X‐ray spectroscopy.ResultsThe inhibition efficiency is 45.5% at 2 g L−1 GDE at 20°C, while it increases to 97.9% when 5 × 10−4 mol L−1 of potassium iodide is added at 25°C. The GDE/iodide ion system follows the Langmuir adsorption isotherm, involves both physical adsorption and chemical adsorption and acts as a mixed‐type inhibitor.ConclusionsIt is found that significant corrosion inhibition can be obtained in a synergistic manner between Ghars date extract and iodide ions for the API 5 L X70 pipeline steel in sulfuric acid.

Corrosion Inhibition in CO2-Saturated Brine by Nd3+ Ions

“…The inductive loop observed in all cases has been attributed to relaxation processes associated with the adsorption of some intermediate species formed during the anodic dissolution process [ 28 , 29 , 30 , 31 , 32 ] or the redissolution of the passive surface [ 31 , 32 ]. In the absence of an inhibitor, it has been associated with the adsorption of species such as FeOH ads [ 3 ] and, in the presence of the inhibitor, it may be due to the adsorption of carbonate compounds.…”