Effect of variation of the structure of amino acids on inhibition of the corrosion of low-alloy steel in ammoniated citric acid solutions

Effect of Alcaligenes sp. on corrosion behavior of X65 steel in simulated offshore oilfield-produced water

“…The -COOH is a functional group for complexing metal ions in EPS, which contains C = O and C -O can complex with iron ions or other metal ions favoring the formation of a dense protective layer (Ghafari et al, 2013). Methionine and cysteine belong to sulfurcontaining Amino acids, and -SH is the most polar group among Amino acids that can easily bind metal ions, the hydrogen ion on -SH can be free in water, while its negative ion combines with metal ions to form a very strong complex protective film, and this very tight protective layer prevents further metal erosion (Abdel-Fatah et al, 2014). The electron clouds on the aromatic rings of aromatic Amino acids (phe, tyr, and try) and the lone pairs of electrons on the heteroatoms interact with the empty orbitals of iron to form insoluble complexes that cover the metal surface, while the hydrophobic benzene rings form a directional upward arrangement that separates the corrosive medium from the surface of X65 steel, thus inhibiting the corrosion (Ashassi-Sorkhabi et al, 2005;Zhang et al, 2008).…”

A review of amino acids used as corrosion inhibitors on iron metal/alloys in aggressive environments

“…It is also pertinent to ascertain the optimal concentration for the effectiveness of an inhibitor. Some inhibitors perform excellently at very small concentrations [89] while others perform well at higher concentrations [90]. Hydrodynamic conditions (i.e., stagnant, or dynamic solution) can also affect the inhibition performance.…”