Two α-aminophosphonics acids as corrosion inhibitors for carbon steel in 0.5M HCl: Electrochemical and DFT/MD simulation.

Abstract

Weight loss, potentiodynamic polarization spectroscopy (Tafel), and electrochemical impedance spectroscopy (EIS) were used to examine the effects of two α-aminophosphonic acids, namely (phenyl-phosphonomethyl-amino)-methyl) phosphonic acid (PHAP) and (propyl-phosphonomethyl-amino)-methyl) phosphonic acid (PRAP), on the surface of carbon steel. At 10−3 M, PHAP and PRAP had maximum efficiencies of 81.58 and 70.21 %, respectively. The topographies of the uninhibited and inhibited surfaces were measured using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The Langmuir adsorption isotherm was followed by the inhibitors' adsorption on the carbon steel surface, and the kinetic parameters (Kads, ΔG°ads, ΔH°ads, and ΔS°ads) were determined for temperatures between 25 and 55 °C. Density functional theory (DFT) was used to compute the quantum chemical parameters using the (B3LYP) method and the 6–31 G (p, d) basis set. Utilizing molecular dynamics simulations (MDS), the interfacial arrangement of the produced chemicals and Fe(110)/H2O was identified. These theoretical discoveries strongly support the results of experiments.