ALKALOID EXTRACT OF ACACIA CATECHU BARK AS GREEN INHIBITOR FOR MILD STEEL CORROSION IN 1 M H2SO4 SOLUTION

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.