The Effect Of Hydroxyl Substituents' Position On Quinoline In The Inhibition Of Aluminium Corrosion In Hydrochloric Acid

The ability of several hydroxyquinolines to inhibit aluminum corrosion and the effect of hydroxyls at 6, 7, and 8 positions on quinolines in hydrochloric acid were experimentally studied by weight loss, EIS, and PDP. To promote weight loss, 6-hydroxyquinoline (6-OHQ), 7-hydroxyquinoline (7-OHQ), and 8-hydroxyquinoline (8-OHQ) were used under different mass and temperature conditions at different HCl concentrations. The adsorption properties of these inhibitors proved to be reliable. Both chemical and physical mechanisms were significant in the Longmuir isotherm. In comparison, 7-hydroxyquinoline performed better than 6-hydroxyquinoline in terms of corrosion inhibition percentage, mass loss, inhibition efficiency, and surface coverage measured by weight loss. Under identical conditions, 8-hydroxyquinoline performed the worst in terms of corrosion inhibition. The inhibition process proceeded more rapidly in each system via first order kinetics. The surface morphology and functional groups were examined by SEM and FTIR before and after the corrosion study. The weight loss and Nyquist plots from the impedance data and parameters both showed the same behavior. The Tafel plot parameters and polarization data both show the same trend. The EIS, PDP, and weight reduction results are relatively consistent. Although each molecule exhibited excellent corrosion inhibition performance, the 7-OHQ molecule is superior to the other two molecules in inhibiting aluminum corrosion.