A Green Approach to the Corrosion Inhibition Effect of Waste Extract on Copper in an Alkaline Environment

Waste extract was examined to inhibit copper corrosion in 0.5 M KOH (alkaline) solutions. The inhibitory action of the waste extract was investigated using potentiodynamic polarization and gravimetric methods. The result indicated that the extract prevented the copper corrosion in the tested environment, achieving 90.68% effectiveness. The polarization test indicates that the extract is a mixed-type corrosion inhibitor, capable of inhibiting both cathodic and anodic processes in the Cu/KOH system. The inhibitory effect was due to the waste extract sticking to the copper surface, which formed a barrier that prevented harmful ions from reaching the metal. The molecules extracted adsorb on the surface of the metal following Langmuir adsorption model, denoting the extract forms a monolayer protective film on the copper surface. Consequently, the waste extract can effectively prevent copper from corroding in an alkaline environment.