ALKALOID EXTRACT OF ACACIA CATECHU BARK AS GREEN INHIBITOR FOR MILD STEEL CORROSION IN 1 M H2SO4 SOLUTION
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Amrit Campus
Abstract
In situ corrosion inhibition in acid cleaning processes by using green inhibitors is at
the forefront in corrosion chemistry. Plant extracts, especially alkaloids, are known to
be good corrosion inhibitors against mild steel corrosion. In this research, alkaloids
extracted from Acacia catechu has been used as green corrosion inhibitor for mild
steel corrosion in 1 M H2SO4 solution. Qualitative chemical tests and FTIR
measurements have been performed to confirm alkaloids in the extract. The weight
loss measurement has been adopted for the study of inhibitor concentration effect as
well as variation of inhibition efficiency for time and temperature. Weight loss
measurement reveals the maximum efficiency of 93.96 % at 3 hrs at 28 C. The 1000
ppm inhibitor can work up to a temperature of 48 C with 84.39 % efficiency. The
inhibition efficiency of extract has been studied by using weight loss and
potentiodynamic polarization methods. Electrochemical measurement results revealed
that the alkaloids act as a mixed type of inhibitor. The inhibition efficiency of 98.91
% and 98.54 % in the 1000 ppm of inhibitor concentration for as-immersed and
immersed conditions, respectively has been achieved. The adsorption isotherm
indicated the physical adsorption of alkaloids. Also, the spontaneous and endothermic
adsorption processes have been indicated by thermodynamic parameters.