INHIBITING EFFECTS OF L-TRYPTOPHAN ON THE CARBON STEEL CORROSION IN ALKALINE SALINE SOLUTION

• DOI: 10.7324/rjc.2017.1031751
• Publication Date: 2017-09-22T02:22:54Z
• Authors: Taghried A. Salman; Alaa Mohammed
• Keywords: Carbon steel; Alkaline protease; Carbon fibers

The inhibiting effect of L-tryptophan, that considered as an eco-friendly compound on the corrosion carbon steel in saline solution ( 3.5% NaCl) at pH 11 was investigated potentiostatically five temperatures range 293-313 K. Five concentrations inhibitor were tested ranging from 5×10 -4 to 1×10 -2 mole L -1 .The addition Ltryptophan alkaline sodium chloride lowered feasibility alloy.On other hand, increased with rise temperature.Carbon rate decreased increasing L-tryptophan concentration reflecting when it is present high solution.The efficiency inhibition (%IE) attaining a maximum value 71.72 % became , and decrease temperature.Adsorption surface obey Langmuir isotherm.Gibbs free energy adsorption -29.07 kJ mol indicates physisorption alloy.Quantum mechanical study using DFT method B3LYP/6-31G basis set applied achieve good relation between chemical structure L-tryptophan.