ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Insights into the high and prolonged inhibition mechanism of pyridoxine hydrochloride as vitamin B6: a new green inhibitor slowing the acidic corrosion of mild steel

Demet Özkır

Department of Chemistry, Faculty of Arts and Sciences, Niğde Ömer Halisdemir University, Niğde, Türkiye

E-mail: dozkir@ohu.edu.tr

Received: 10 January 2024  Accepted: 15 May 2024

Abstract:

This study aimed to assess the green corrosion inhibitor effect of the compound known as vitamin B6 and called pyridoxine hydrochloride (PYB6) on mild steel in 1.0 M HCl solution by some electrochemical techniques such as linear polarization resistance (LPR), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) for various concentrations and durations. In order to examine the interplay between PYB6 and mild steel surface, various adsorption isotherms were tried and the best correlation constant among them was acquired by Langmuir adsorption isotherm. Experimental data calculated by the EIS method showed that the lowest inhibition efficiency value was 70.7% for 1.0 × 10⁻⁵ M PYB6 solution concentration after one hour of immersion, while the highest inhibition efficiency value was 96.8% for 1.0 × 10⁻³ M PYB6 solution concentration after 48 h of immersion. The finding of zero charge potential (PZC) of mild steel was found to be − 0.010 V in the solution containing the highest concentration of PYB6, which supports that the inhibition mechanism creates a protective film layer on the surface of mild steel with protonated PYB6 molecules. The surface analysis of PYB6 onto mild steel in a hydrochloric acid solution was also examined utilizing techniques such as atomic force microscope (AFM) and field emission scanning electron microscope (FE-SEM). It was concluded that PYB6 green inhibitor formed a presentative adsorption film on the surface of mild steel, effectively reducing its corrosion.

Graphical abstract

Keywords: Pyridoxine; Vitamin B6; EIS; PZC; FE-SEM; AFM

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-024-03524-0

Chemical Papers 78 (10) 6035–6052 (2024)