Corrosion inhibition of mild steel in HCL solution by pectin

• Pectin is an efficient inhibitor for mild steel corrosion in HCl.
• Inhibition results from surface geometric blocking by chemisorbed species.
• UV–visible data point to the formation of a complex between pectin and Fe2+ ions.

This work describes the successful performance of pectin as an eco-friendly corrosion inhibitor for mild steel in HCl solution. The inhibition mechanism is discussed considering thermodynamics of adsorption and kinetics of the electrochemical reactions. Inhibition efficiency increases with temperature while the activation energy for the corrosion rate decreases with the addition of pectin. Pectin is a mixed-type inhibitor and the mode of inhibition results from the geometric blocking effect of chemisorbed inhibitive species at the metal surface. Spectroscopic analysis points to the formation of a complex between pectin and Fe2+ ions released during the corrosion reaction.