Pipeline steel protection in oil well acidizing fluids using expired pharmaceutical agent
Nkem B. Iroha and Ngozi J. Maduelosi
The protection performance of expired Pregabalin for X60 pipeline steel corrosion in 15% HCl solution was investigated using weight loss technique, electrochemical measurements and scanning electron microscopy (SEM) analysis. The results show that Pregabalin inhibited the acid induced corrosion of X60 steel and its inhibition efficiency increases with inhibitor concentration. Polarization measurements indicate that the inhibitor act as mixed type inhibitor. Impedance measurements suggest that the corrosion reaction is controlled by charge transfer process. Weight loss measurements carried out at different temperature showed that adsorption of the expired drug involve physisorption mechanism. The adsorption followed the Langmuir isotherm with negative values of Gibbs free energy of adsorption, suggesting a stable and spontaneous inhibition process. SEM analysis confirmed the existence of a protective film of the inhibitor on X60 steel surface.