Experimental assessment and molecular-level exploration of the mechanism of action of Nettle (Urtica dioica L.) plant extract as an eco-friendly corrosion inhibitor for X38 mild steel in sulfuric acidic medium

Abstract

The development of green corrosion inhibitors has gained considerable importance in recent years due to their minimal environmental impact and sustainable nature. As industries increasingly seek eco-friendly alternatives to conventional corrosion inhibitors, research focused on identifying effective and renewable corrosion protection solutions becomes imperative. The main purpose of this study is to evaluate the inhibition action of Nettle extract (NE) (Urtica dioica L.) as a promising green corrosion inhibitor for mild steel in a 0.5 mol/L H2SO4 medium. In this work, the corrosion protection performance of NE was assessed using weight loss, electrochemical, surface characterization, and computational chemistry methods. The results indicated that NE acted as an effective corrosion inhibitor, with inhibition efficiency reaching a maximum of 90% at a concentration of 4 g L-1. Polarization studies revealed that NE functions as a mixed-type inhibitor, while electrochemical impedance spectroscopy (EIS) results showed an increase in charge transfer resistance and a decrease in double layer capacitance values in the presence of NE. Surface characterization analysis confirmed the formation of a protective NE layer on the steel surface. Furthermore, Density-functional tight-binding (DFTB) simulations identified Quercetin, Kaempferol, and Serotonin as having stronger chemical bonding with the Fe(110) surface, while Histamine molecules exhibited physical interactions with iron atoms. This comprehensive evaluation of NE's inhibition action not only supports its potential as an eco-friendly inhibitor for mild steel corrosion protection but also contributes to the development of sustainable corrosion control strategies.