Phytochemical analyses and thermodynamic studies of ethanol extract of <i>Dracaena trifasciata</i> (Laurentii) as corrosion inhibitor for mild steel in 1.0 m HCL solution

The increasing awareness of green chemistry and the research of green corrosion inhibitors have become a popular direction for many corrosion researchers thereby replacing harmful synthetic chemicals. Although numerous plants and their phytochemicals have been reported as anti-corrosive agents, vast majority of plants have not yet been studied for their anti-corrosive activity. Based on this, the investigation of the inhibitory effect of ethanol extract of Dracaena trifasciata (Laurentii) on mild steel in 1.0 M HCl was studied using weight loss analysis at concentrations 0.2, 0.5, 1.0, 1.5 and 2.0 g/L from 303 K-333 K. From the study, weight loss increased with increase in temperature and time, and decreased with increase in concentration of the inhibitor. At 2.0 g/L, the extract exhibited higher inhibition efficiency of 60% at 303 K. Thermodynamic parameters revealed adsorption process as spontaneous. Enthalpy (∆Ho ads) values were positive indicating the adsorption process as endothermic and entropy (∆So ads) values were negative showing a decrease in the disorderliness of the system. The adsorption of Dracaena trifasciata (Laurentii) obeyed Freundlich adsorption isotherm. GC-MS analysis showed a total of 24 bioactive compounds with Isopropyl linoleate and Propyleneglycol monooleate, being the most abundant compounds (14.475%). Functional groups obtained from FT-IR analysis of the extract were ester, acid anhydride, alcohol, alkane, alkene and carboxylic acids.