Phytochemical Analysis, Antioxidant and Anticorrosive Activities of Thymus Algeriensis Extracts

The present work is devoted to study the Thymus Algeriensis (TA) extracts as antioxidants and green corrosion inhibitors of mild steel (MS) in 1 M HCl medium at 303 K. The extract from aerial parts of Thymus Algeriensis were obtained by distillation and analyzed. Antioxidant activity of methanolic extract of TA was examined by using both DPPH radical scavenging and β-carotene-linoleic acid bleaching and likened with ascorbic acid and BHA (butylated hydroxyanisole) used as reference compounds. Corrosion inhibition of of mild steel (MS) in HCl by ethyl acetate (EATA) and methanol (EMTA) extracts of TA was studied using weight loss and electrochemical techniques. TA extract was found to be a better inhibitor. Indeed, the inhibition efficiency increased with increase EATA and EMTA concentration but decreased with rise in temperature. The variation of inhibitory efficacy with temperature point towards physical adsorption which is supported by the kinetic and thermodynamic parameters derived from the experimental data. Polarization studies show that the EATA and EMTA act as mixed typed inhibitor. Inhibitive effect was afforded by adsorption of the EATA and EMTA components which was found to accord with Langmuir adsorption isotherm.