Influence of purine on copper behavior in neutral and alkaline sulfate solutions

The effect of purine (concentration range of 1.00 × 10^?6?C1.00 × 10^?2 M) on the behavior of copper in a 0.5 M Na₂SO₄ solution (pH 7 and pH 9) was studied using the open circuit potential measurement, potentiodynamic polarization, and chronoamperometry. Potentiodynamic polarization shows that purine acts as a copper corrosion inhibitor in both alkaline and neutral sulfate solutions. The efficiency of inhibition increases as the purine concentration increases. Chronoamperometric results follow the same trend as the results of potentiodynamic polarization. The inhibition effect can also be observed visually by microscopic examination of the electrode surface. Purine is adsorbed on copper surface according to the Langmuir adsorption isotherm.