Effect of Sodium Molybdate on Corrosion Inhibition of 1H-Benzotriale for Copper in Simulated Sea Water

The cooling systems are widely used in power plants, manufacturing industries and refineries for the sake of reducing system heats and an increase in operational efficiency. Copper is widely used in cooling systems due to its high thermal conductivity. Corrosion of copper is one of main problems in these industries. The use of corrosion inhibitors is a common method to control the corrosion in cooling systems. Various inhibitors are usually used to protect the different metals in cooling systems. The synergistic or antagonistic effect of inhibitors on each other may be influenced on inhibition efficiency. The inhibition effect of 1H-benzotriazole (BTA) on corrosion of copper has been investigated in simulated sea water in the presence and absence of sodium molybdate (SM) using weight loss, Tafel polarization and electrochemical impedance spectrometry (EIS) methods. The results indicated that adsorption of BTA and SM on copper surface obeyed from Langmuir adsorption isotherm. The adsorption energy values for BTA and SM on copper surface was obtained -33.88 and -21.22 kJ/mol, respectively. The absorption of sodium molybdate promoted the stability of surface oxides on copper surface which in turn has a synergistic effect on the inhibition effectiveness of BTA. The inhibition of SM and BTA has been attributed to stabilize the effect of surface oxides and the formation of a protective complex layer, respectively.