Investigation of the Inhibition Effect of Nontoxic Purine Derivatives on the Carbon Steel Corrosion in 0.5 M H2SO4 Solution

The behavior of carbon steel in 0.5 M H2SO4 in the presence of novel purine inhibitors namely 1H-pyrazolo[3,4-d]pyrimidin-4(2H)-one (P1) and 6-[(1-methyl-4-nitro-5-imidazolyl)sulfanyl]purine (P2) in the concentration range (1×10−4 − 5×10−3 M) was studied using weight loss, open circuit potential, potentiodynamic polarization electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) techniques. Potentiodynamic polarization shows that P1 and P2 act as mixed-type inhibitors. The adsorption of inhibitors on metal followed Langmuir’s adsorption isotherm. SEM images showed that the inhibitor molecules form a good protective film on the carbon steel surface.