A Study of Factors Influencing on Dissolution Behavior of Copper in Orthophosphoric Acid Using Rotating Cylinder Electrode (RCE) and Rotating Disc Electrode (RDE)

The rotating cylinder electrode (RCE) and rotating disc electrode (RDE) are used for investigation of dissolution behavior of copper in presence of surfactant (Triton x-100, SDS and CPC). The dissolution of copper was studied in 8M H3PO4 as a function of surfactant concentration (5x10(-7) -1x 10(-2) M) at 25 degrees C. Measurements were conducted based on potentiodynamic polarization method. The inhibition behavior of low cost surfactants compounds was inspected. The inhibition efficiency of these surfactants was depending on their concentration and their chemical structure. The rotation speed of RCE and RDE effect was explored. The adsorption of surfactants on copper surface was found to be not obeying Langmuir and followed Kinetic-thermodynamic adsorption isotherm. Activation energy, the pre-exponential factor and adsorption free energy Delta G(ads)degrees, are calculated and discussed. Scanning electron microscope (SEM) was used to characterize the copper surface. Different reaction conditions and the physical properties of solutions are studied to obtain dimensionless correlation among all these parameters. Experimental result showed that the inhibition efficiency of SAS improved in presence of alcohols. The synergism parameters are found to be greater than unity indicating that co-operative adsorption of alcohols and SAS.