Abstract

ANTICORROSION ACTIVITY OF CACTUS EXTRACT ON IRON METAL SHEETS

Tessema Derbe* and Worku Batu

ABSTRACT

The anticorrosion activity of CE on iron metal sheets was investigated using weight loss method. The result revealed that the rate of corrosion activity is decreased from 7.887x10-3 to 1.7x10-3 mmpy with increasing dose of inhibitors from 0mL to 9mL. But the inhibition efficiency and surface coverage area are increased from 49% to 77% and 0.49 to 0.77, respectively with increasing inhibitor dose from 1mL to 9mL. This is due the fact that as the concentration of inhibitors increased, a larger number of inhibitors molecule is get adsorbed on the metal surface which results more coverage of the corroded metal surface. This makes the metal too difficult from further corrosion by the corrosion agents. In the other hand, the inhibition efficiency and surface coverage area of CE are lower at higher temperature. This is due to the fact that at an elevated temperature desorption of preadsorbed inhibitor molecules occur from metal surface; decomposition and rearrangement of some inhibitors may take place which increases corrosion rate at uninhibited metal surface. Adsorption of CE on iron metal sheets are obeyed the Langmuir, Temkin and Frumkin adsorption isotherms. The positive value of activation energy (Ea) and the negative value of free energy of adsorption (ΔGoad) support the physical adsorption of CE iron metal sheets. The large values of the thermodynamic parameters at high dose of CE indicate the stable interaction between CE and iron metal sheets.

Keywords: Corrosion, anticorrosion activities, metal sheet, corrosion agent, adsorption and cactus extract (CE).