Potentiodynamic polarization, surface analyses and computational studies of a 1,3,4-thiadiazole compound as a corrosion inhibitor for Iraqi kerosene tanks

Abstract

Abstract The inhibition efficiency of thiadiazole derivative namely (4-(5-(p-tolyl)-1,3,4-thiadiazol-2-yl)phenol, TTP) has been analyzed by potentiodynamic polarization technique to reduce the rate of corrosion in low carbon steel (285Gr C) in corrosive medium (NACE ID 196/kerosene). The investigation results were indicated that the TTP compound has shown maximum inhibition efficiency (87.18%) in 400 ppm at 333 K and it acts as a mixed-type inhibitor according to Tafel curves. The influence of temperature and inhibitor concentration on the percentage of inhibition has been studied and discussed. The data showed that the inhibitor was adsorbed physically on the steel surface and it follows the Langmuir model. The microstructure of the tested samples was analyzed to show the chemical composition of the components in the uninhibited and inhibited surface by energy dispersive X-ray microanalysis (EDXMA). In addition, different morphological techniques, such as scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been applied to confirm the interaction between the inhibitor and metallic surface. The correlation of inhibitor molecules on steel surface was evaluated by the ATR-FTIR spectrophotometer. The biological effect of the inhibitor was also examined towards some types of bacteria that can degrade the hydrocarbon compounds. The theoretical results calculated by density functional theory (DFT) were related well with the experimental finding obtained from the performance of the TTP inhibitor.