A novel corrosion inhibitor for copper in sulfuric acid media: Complexation of iodide ions with Benincasa Hispida leaf extract

Abstract

In the context of green and low-carbon development, the rapid development of industry brings the problem of metal corrosion costs increase, metal corrosion protection methods are of great concern. Extracts from Benincasa hispida leaves (BHLE), which were obtained through pressurised liquid extraction, were employed as a inhibitor for copper corrosion in 0.5 M H₂SO₄. Their composition and anti-corrosion properties were subsequently analyzed and evaluated. The electrochemical analysis results indicated that BHLE functions as a cathodic-type corrosion inhibitor. The anti-corrosion performance intensifies with the increase in concentration but diminishes gradually as the temperature rises, when the concentration of BHLE is 400 mg/L, the corrosion inhibition efficiency can reach 91.82 %, when the concentration of added potassium iodide reaches 16 mg/L the slow-release efficiency of the compounded corrosion inhibitor reaches 96.92 %. The addition of I⁻ strengthens the inhibition efficiency through the adsorption form dominated by competitive adsorption. The adsorption of BHLE onto the surface of copper follows the Langmuir monolayer adsorption model.