Tryptamine as a green iron corrosion inhibitor in 0.5M deaerated sulphuric acid

The inhibition effects of tryptamine (TA) on the corrosion behaviour of ARMCO iron in 0.5 M deaerated H2 SO4 (in the 25–55 ºC temperature range) was studied in both short and long time tests (1, 24 and 72 h) by means of potentiodynamic curves (PCM) and electro-chemical impedance spectroscopy (EIS). TA was found to be an effective ARMCO iron inhibitor, even at 55 ºC and 72 h, but only at 10 mM. At this concentration the inhibition percentages (IP%), calculated by PCM and EIS, ranged from 90% to 99% and did not diminish over time and as the temperature increased. TA adsorption followed Bockris–Swinkels' isotherm (x = 1). The thermodynamic data indicated that, in the more concentrated solutions, TA also chemisorbed on the iron surface.