Seed Extract of Dypsis lutescens as Ecofriendly Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Medium G. Rexin Thusnavis* 1 , T. V. Archana 1 , K. P. Vinod Kumar 2 , M. Sankara Narayanan Pillai 3 1 Department of Chemistry, Pioneer kumaraswamy college, Nagercoil-629003, Tamil Nadu, India 2 Department of Chemistry, University College of Engineering, Nagercoil, Anna University Tirunelveli, Nagercoil-629004, Tamil Nadu, India. 3 Department of Chemistry, Noorul Islam University, Kumaracoil, Nagercoil, Tamilnadu, India. Abstract : The seed extract of Dypsis lutescens, had been analyzed for mild steel corrosion inhibition in acid medium with weight loss, thermodynamic, adsorption and electrochemical parameters. The results reflected that the extract is a potential corrosion inhibitor. IR spectra and SEM photographs recorded for functional group and surface modification analysis of mild steel, were agreeing with other parameters. Entire study revealed that the inhibitor works through adsorption of its molecules over the mild steel. From this study it is inferred that the seed extract of D. lutescens is an efficient, eco-friendly and alternate corrosion inhibitor for mild steel in acid medium. Key words : D. Lutescens, mildsteel, corrosion, polarization, impedance, eco-friendly. Introduction Mild steel is widely used as a constructional material for various industrial applications due to its high mechanical properties and low cost. Several corrosion problems aggravate by the excessive use of hydrochloric acid in pickling, rescaling and cleaning functions on mild steel surface 1 . Corrosion is an electrochemical process that leads to the flow of electric current in acidic media which results in metal loss. Mild steel corrosion in acidic media is significant because of the increased industrial applications of acid solutions. Use of inhibitors is one of the most practical methods for protection of metal against corrosion especially in acid solutions to prevent unexpected metal dissolution and acid consumption 2-5 . The effectiveness of inhibitor depends upon the interaction, adsorption of molecules and ions on metal surface 6 . Not long, the researches on plant extracts are in progress for corrosion inhibition and the most of them are proved to be successful. Phyllanthus amarus 7 , vegetal tannins 8 , Parthenium Hystophrous 9 , Ficus Exasperata 10 , Citrus aurantiifolia 11 , Eclipta Alba 12 , G. Rexin Thusnavis et al /International Journal of ChemTech Research, 2020,13(1): 149-158. DOI= http://dx.doi.org/10.20902/IJCTR.2019.130118 International Journal of ChemTech Research CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.13 No.01, pp 149-158, 2020