Inhibition of Acid Descaling and Pickling Effects on API 5CT Carbon Steel Using Schiff Base Ligand (C24H21N5O2) in 1 M H2SO4 Solution

Abstract

The objective of this paper was to investigate the inhibition of acid descaling and pickling effects on API 5CT carbon steel using Schiff base ligand (C₂₄H₂₁N₅O₂) in 1 M H2SO4 solution using  Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) and Weight Loss (WL) techniques. FTIR spectroscopy shows that there was a strong adsorption of SFBL on the carbon steel surface due to formation of a complex surface film. Corrosion rate of carbon steel decreased exceedingly from 0.0155 to 0.0002 while inhibition efficiency of SFBL rose from 78.8 % to 98.9 % between 20 ppm and 100 ppm respectively. PDP measurements revealed a mixed type inhibitor. EIS measurement reveals that the increasing charge transfer resistance was directly proportional to the increase inhibitor concentration and the double layer capacitance dropped from 1.98 to 0.61 indicating a stronger inhibition.