Ionic salt (4-ethoxybenzyl)-triphenylphosphonium bromide as a green corrosion inhibitor on mild steel in acidic medium: experimental and theoretical evaluation

Abstract

A new phosphonium salt (4-ethoxybenzyl)-triphenylphosphonium bromide (EBTPPB), having different substituents attached to phosphorous and having different anions, is investigated as an inhibitor for mild steel (MS) corrosion in 0.5 M H 2 SO 4 solutions via electrochemical polarization and electrochemical impedance (EI) spectroscopy. Electrochemical results show that EBTPPB compound has practically good inhibiting features for MS corrosion in the corrosive medium with efficiencies of approximately 98% at an optimum 10 À2 M concentration. The inhibition is of a mixed cathodic-anodic type. Passive potential (E pp ) of the modified steel specimen is in the inactive region and thus inhibits the corrosion process.Langmuir Adsorption (LA) isotherm was performed to provide precise information on the adsorption behavior of the ionic salt. It exhibits both physisorption and predominantly chemisorption mechanism on MS surface. Scanning Electron Microscopy (SEM) associated with Energy Dispersion X-ray (EDX) and Atomic Force Microscopy (AFM) assessment of the electrode surface is consistent with the existence of adsorbing screen of EBTPPB molecules. An apparent connection was ascertained between the experimental corrosion inhibition efficiency (IE%) and the theoretical parameters using quantum chemical calculations.

Molecular Assembly between Weak Crosslinking Cyclodextrin Polymer and trans-Cinnamaldehyde for Corrosion Inhibition towards Mild Steel in 3.5% NaCl Solution: Experimental and Theoretical Studies

“…The steric effect of narrow rim assembling is more pronounced than that of wide rim assembly, which is conducive to forming intensive non-covalent interactions (e.g., van der Waals’ force, hydrogen bond and hydrophobic effect) between host and guest moieties. The enhanced non-covalent interactions result in elevated E n and E p , and thus increase the value of E t [36].…”

Structural Effect in Ionic Liquids Is the Vital Role to Enhance the Corrosion Protection of Metals in Acid Cleaning Process

“…The above facts are the same as above in the phosphonium bromide molecule. The energy difference is much higher when substituting the 4-ethoxybenzyl group in the phosphonium [35] cationic part compared to butyl substitution [36]. Likewise, increasing the carbon chain length on the heterocyclic group also decreases the ∆E considerably [37].…”

Effect of Plating Materials on the Corrosion Properties of Steel Alloy 4130

“…The mechanical properties of this alloy can be improved by heat treatment [12]. The capacity and strength ductility of these alloys can be achieved by adding some elements such as chromium, nickel, and molybdenum [13][14][15][16]. To assure about the infrastructures in industrial manufactures to spend long time without any detrioration or degradation of steel alloy, the protection of metallic strucures from corrosion is necessity.…”