The effect of Artemisia annua L. extract on microbiologically influenced corrosion of A36 steel caused by Pseudomonas aeruginosa.

The protective effect of A. annua against microbiologically influenced corrosion (MIC) of A36 steel caused by P. aeruginosa (PA) in a simulated marine environment was investigated using electrochemical, spectroscopic, and surface techniques. PA was found to accelerate the local dissolution of A36 which led to the formation of a porous α-FeOOH and γ-FeOOH surface layer. 2D and 3D profiles of treated coupons, obtained by optical profilometer, revealed the formation of crevices in the presence of PA. On the contrary, adding A. annua to the biotic medium led to the formation of a thinner, more uniform surface without significant damage. Electrochemical data showed that the addition of A. annua prevented the MIC of A36 steel with an inhibition efficiency of 60%. The protective effect was attributed to the formation of a more compact FeO surface layer, as well as the adsorption of phenolics, such as caffeic acid and its derivatives on the A36 steel surfaces, as detected by FTIR and SEM-EDS analysis. ICP-OES confirmed that Fe and Cr species more readily diffuse from A36 steel surfaces incubated in biotic media (Fe; 1516.35 ± 7.94 μg L cm, Cr; 11.77 ± 0.40 μg L cm) compared to the inhibited media (Fe; 35.01 ± 0.28 μg L cm, Cr; 1.58 ± 0.01 μg L cm).