INHIBITIVE EFFECT OF WRIGHTIA TINCTORIA LEAVES AS GREEN INHIBITOR FOR MILD STEEL IN ACID MEDIUM

The inhibition efficacy of Wrightia tinctoria leaves (WTL) extract on mild steel in 1.0N hydrochloric acid with various exposure time (24 to 360hrs) and temperature (313 to 333K) are investigated by mass loss measurements. The value of inhibition efficiency is increased with increase of inhibitor concentration and gradually decreased with rise in temperature is suggestive of physisorption. The adsorption of WTL onto the mild steel surface is found to follow the Langmuir adsorption isotherm. Both kinetic (activation energy and change in heat of absorption) as well as thermodynamics parameters (adsorption of enthalpy, entropy and Gibbs free energy) are calculated and discussed in details. The characterization of alcoholic extract of inhibitor and corrosion products formed on the metal surface is analyzed by UV, FT-IR and SEM spectral studies.