**4. Conclusion**

The inhibition efficiency (%IE) of TRE increases with the increase of extract concentration. EIS results showed that the double-layer capacitance (Cdl) decreases and charge transfer resistance (Rct) increases with the time of immersion in the extract. The inhibitor showed maximum inhibition efficiency (%IE), 88.9% at 8 g/ 100 mL concentration. The inhibition efficiency (%IE) of TRE decreased with temperature, which leads to a decrease in activation energy (Ea) of the corrosion process.

The activation energy value of Ea <sup>=</sup> 20 kJ mol<sup>1</sup> indicates that the adsorption process is spontaneous and the is physical adsorption. Langmuir adsorption isotherm and SEM studies showed that TRE inhibitions occur through adsorption mechanism. The results of SEM and EDX have been shown to form a protective film on the iron surface.
