Kappaphycus alvarezii – A marine red alga as a green inhibitor for acid corrosion of mild steel

The anticorrosion potential of Kappaphycus alvarezii on mild steel in both 1 M HCl and H 2 SO 4 media has been studied using weight loss method at three different temperatures, electrochemical measurements, and surface analyses. The results revealed the inhibitive effect of K. alvarezii . The inhibition efficiency was found to increase with increasing concentration of the algal extract but decreased with increase in temperature which is attributed to the physisorption. The adsorption of the extract on the mild steel surface obeys the Temkin adsorption isotherm. Further, scanning electron microscope (SEM) and atomic force microscope (AFM) analyses supported the inhibitive action of this red alga by the formation of protective layer over the mild steel surface.