4-aminobenzenesulfonic acid as effective corrosion inhibitor for carbon steel in hydrochloric acid

Abstract

The inhibitive activity of 4-aminobenzenesulfonic acid (SA) on the corrosion of carbon steel in 1 M HCl medium has been studied by weight loss, potentiodynamic, and impedance spectroscopy measurements. Experimental results reveal that sulphanilic acid goes about as an inhibitor in the corrosive condition. The inhibition efficiency increases with an increase in the SA concentration. The greatest inhibition efficiency is 92.14% at SA concentration 1000 ppm. Thermodynamic and kinetic parameters have been got from temperature studies. Electrochemical estimation reveals that sulphanilic acid acts as a mixed inhibitor and the adsorption isotherm follows Langmuir. The surface examination by SEM and surface composition was evaluated using EDX that shows the presence of a protective layer of SA molecules on the surface.