Experimental and Theoretical Evaluation of Pentoxifylline as a Sustainable Corrosion Inhibitor for Medium Carbon Steel in HCl
DOI:
https://doi.org/10.31489/2959-0663/3-26-15Keywords:
green inhibitor, corrosion inhibitor, adsorption, pentoxifylline, medium carbon steel, HCl, adsorption isotherms, Tafel polarization, Langmuir isotherm, DFT calculationsAbstract
This study aims to evaluate pentoxifylline (PTF), a pharmaceutical drug, as a sustainable green corrosion inhibitor for medium carbon steel in a 0.2 M HCl environment, addressing the critical need for non-toxic industrial alternatives. Experimental investigations were conducted using gravimetric weight loss measurements, hydrogen evolution tests, and electrochemical Tafel polarization across a temperature range of 293.15 to 313.15 K. Theoretical analyses, including Density Functional Theory (DFT) and Monte Carlo simulations, were further employed to explore molecular reactivity and adsorption behavior on the Fe (110) surface. The results revealed that inhibition efficiency increases with PTF concentration, reaching a maximum of 90.0 % at 500 ppm and 293.15 K. Thermodynamic parameters indicated that the process follows the Langmuir isotherm through a spontaneous physical adsorption mechanism. Electrochemical data confirmed that PTF acts as a mixed-type inhibitor, effectively suppressing both anodic metal dissolution and cathodic hydrogen evolution. Furthermore, the addition of iodide ions demonstrated a significant synergistic effect, enhancing the protective capacity to 99.4 %. In conclusion, PTF serves as a highly effective eco-friendly alternative for steel protection. Future research is recommended to investigate the long-term stability of PTF under dynamic industrial flow conditions.
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