Adsorption and corrosion inhibition of amphiphilic compounds on steel pipeline grade API 5L X52 in sulphuric acid 1 M

Abstract

The effect of seven amphiphilic compounds, on steel API 5L X52 corrosion in sulphuric acid 1 M solution was studied by potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS). Potentiodynamic polarization curves indicated that these compounds acted mainly as cathodic type inhibitors. The EIS spectrums showed that the mechanism of corrosion inhibition is mainly a faradic process, the spectra were fitted with one electrical equivalent circuit (EEC) using a constant phase element (CPE). Double layer capacitance associated with CPE was also obtained. Langmuir, Temkin, and Henry adsorption isotherm described the experimental findings. This information suggested that organic molecules were adsorbed on active sites on metal surface avoiding contact of corrosive media with steel surface, having adsorbate molecules low molecular interaction between them even with the presence of more amphiphilic molecules on the steel surface as concentration got higher values.

Environmentally Friendly Corrosion Inhibitors

“…Ionic liquids (ILs) deserve particular attention due to the rapid grown in the number of applications in the Oil Industry [134], and particularly within the topic of synthetic EFCIs, these have shown an effective performance as inhibitors of various metals and alloys [135][136][137][138][139][140][141][142][143][144][145][146][147][148][149][150][151].…”

Corrosion inhibition of mild steel by an imidazolium ionic liquid compound: the effect of pH and surface pre-corrosion

“…[2][3][4][5][6][7][8] Imidazolium ionic liquids with a carbon chain are typical examples of these compounds; the aromatic ring is generally believed to provide bonding between molecules and the metallic surfaces, while the carbon chain tail forms a hydrophobic lm that heightens the effect of surface coverage and protection. [8][9][10][11][12][13][14][15][16] Ionic liquids are traditionally well known as environmentally friendly solvents, and are representative component of green chemistry and clean industrial technology. They can be used for chemical synthesis, reaction catalytic processes, gas handling, electrochemistry, fuel cells, etc.…”

Porphyrins as Corrosion Inhibitors for N80 Steel in 3.5% NaCl Solution: Electrochemical, Quantum Chemical, QSAR and Monte Carlo Simulations Studies

“…The CPE is often used in an equivalent circuit in place of capacitance in order to ensure a more accurate curve fitting [20]. The capacitance associated with the CPE can be expressed as [21,22,23,24]: ZCPE=(YoRct1−n)true1n where, Y o is the CPE constant (in Ω −1 ·s n ·cm −2 ), j is the square root of −1, and n is the phase shift, which can be used as a gauge of the heterogeneity or roughness of the surface. The CPE can be expressed by the values of n , such that for resistance ( n = 0, Y = R ), capacitance ( n = 1, Y = C ), inductance ( n = −1, Y = L ) or Warburg impedance ( n = 0.5, Y = W ).…”