Insight into the corrosion inhibition performance of Capsicum annuum L. leaf extract as corrosion inhibitor for copper in sulfuric acid medium

Abstract

Background

Metal corrosion and protection have always been popular areas of research. Corrosion inhibitors are of great significance in metal corrosion protection. In this study, pure water extraction technical was utilized to acquire Capsicum annuum L. leaf extract (CALLE). The corrosion protection property of CALLE was revealed through a combination of theoretical and experimental using electrochemical methods, theoretical calculation and morphology analysis of surface.

Methods

In this study, we used polarization curve method and electrochemical impedance spectroscopy test to evaluate the corrosion inhibition performance of CALLE. Electrochemical test reveals that CALLE has exhibit high protection ability about corrosion. The corrosion inhibition efficiency can grow about 94 % as the contain rises 500 mg/L. As the temperature rises, its resistance efficiency can still be stabilized above 90 %. The test analyses of SEM and AFM convincing demonstration that CALLE can efficiently inhibit occurring about the corrosion in H₂SO₄ for copper.

Significant findings

It results reveal that the four effective components for CALLE can emerge excellent inhibition ability through theoretical analysis of theoretical calculation. The adsorption isotherm model shows that the active ingredient about CALLE was adsorbed correspond with the Langmuir adsorption isotherm model, and exist simultaneously physical and chemical adsorption. CALLE prepared by pure water extraction method can effectively reduce the cost of corrosion inhibitor.