Colorimetric evaluation of the corrosion rate of steel in acidic media in the presence of pentoxifylline drug and KI

• A. AL-abbasi¹ and H. Sida^1,2

¹ Chemistry Department, Faculty of Science/Sebha University, PO Box 18758, Libya
² Scientific Research Consultation Centre, Sebha University, Sebha, PO Box 18758, Libya

Abstract: This work employed a simple colorimetric method (UV-Vis spectroscopy) to measure the concentration of ferrous ions resulting from steel corrosion by using the ortho-phenanthroline method. ortho-Phenanthroline is a chelating agent that forms a stable ferrous complex with ferrous ions. Thus, this colorimetric method was used to measure the characteristics of corrosion and inhibition processes. Consequently, the properties of the expired pentoxifylline medication were assessed as an anti-corrosion agent for steel in a 0.2 M HCl solution. The concentration of dissolved iron was used to calculate the inhibition efficiency and corrosion rate. Additionally, studies on the synergistic impacts of pentoxifylline and potassium iodide (KI) have been conducted. After adding potassium iodide, the maximal pentoxifylline inhibitory efficiency of 88% rose to 94%. The free energy of adsorption was computed by fitting several adsorption isotherms. The limitations of this method include the use of the Beer–Lambert equation, which limits the measurement of ferrous ions in corrosive environments to a maximum of 21 parts per million.

Keywords: pentoxifylline, colorimetry, ortho-phenanthroline, adsorption

Int. J. Corros. Scale Inhib., 2024, 13, no. 2, 995-1011
doi: 10.17675/2305-6894-2024-13-2-19

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