Thermodynamic and adsorption studies for corrosion inhibition of mild steel in aqueous media by Sargasam swartzii (Brown algae)

The phaeophyceae or brown algae is a large group of marine multicelluar algae and play an important role in marine environments both as food,medicines and industrial purposes. in present study,the inhibition effect of methanolic extract of sargassum swartzii (brown algae) and zn 2+ ions (100 ppm) on the corrosion of mild steel in aqueous medium containing 60ppm cl- ion was studied by weight loss method at 303 k - 343 k. the energy of activation,adsorption and thermodynamic parameters were evaluated from the results of temperature study. the inhibition efficiency increased with increase in the inhibitor concentration and decreased with rise in temperature. sargassum swartzii (ss) extract is brought about by the increasing its activation energy(ea) as a result of adsorption is physical adsorption. the adsorption of sargassum swartzii on mild steel surface was found to obey langmuir,temkin and freundlich adsorption isotherms. δg°ads value indicated a strong and spontaneous adsorption of the ss extract components on the metal surface. thus,it can be concluded that sargassum swartzii - zn2+ inhibitor system acted as a good inhibitor in aqueous medium.