Experimental and theoretical studies on the corrosion inhibition on the surface of C-steel in hydrochloric acid solutions using N1, N1'-(ethane-1,2-diyl)bis(N2-(4-(di-methylamino)benzylidene)ethane-1,2-diamine)

Abstract

The inhibition effect of N1,N1'-(ethane-1,2-diyl)bis(N2-(4-dimethyl-amino)benzylidene)-ethane-1,2-diamine), (EDDB) on the corrosion of C-steel in 1.0 M HCl solution was investigated using gasometry, gravimetry, potentiodynamic polarization, and electrochemical impedance spectroscopy. The impact of temperature and inhibitor concentration were explored to illustrate the mechanism of inhibition. The data showed that EDDB is a good inhibitor for the corrosion of C-steel in 1.0 M HCl solution. The inhibition is based on adsorption phenomena, which correlates to the Langmuir adsorption model. The inhibition efficiency increase with the EDDB concentration to reach a maximum value of 95.2% at 0.005 M and 25 °C. Potentiodynamic polarization data confirmed that the EDDB behaves as a mixed-type inhibitor. The negative values of ΔGoads confirm the stability of the formed film on the C-steel with a spontaneous process and take values between – 35.34 and - 39 kJ/mol depending on the temperature which confirms the physical- and chemisorption mechanism. The SEM/EDS data disclosed that the carbon steel was protected by the EDDB inhibitor. DFT computations and MC simulation were achieved on the EDDB Schiff-base inhibitor to correlate with experimental data. The results obtained from the different methods are in good agreement.