Evaluation of Eulychnia acida and Echinopsis chiloensis (Cactaceae) extracts in inhibiting corrosion of carbon steel in HCl solution

Abstract

In the present study, the activity of extracts obtained from the stems of two endemic species of the central–northern region of Chile (Eulychnia acida [Copao] and Echinopsis chiloensis [Quisco]), was evaluated as potential corrosion inhibitors for carbon steel in 0.1 M HCl. The total content of phenols and flavonoids in the extracts was determined, and the main components were identified by high‐performance liquid chromatography–mass spectrometry, being similar in both species. The inhibition efficiency of extracts was evaluated by mass loss measures, Tafel polarization curves, and electrochemical impedance spectroscopy. The assay results showed similar values in inhibition percentages, around 88% at extract concentrations of 1,500 ppm. The adsorption on the steel surface followed the Langmuir model adsorption isotherm, whose thermodynamic parameters (ΔG°ads for Copao and Quisco, −17.81 and −17.70 kJ/mol, respectively) suggest a physisorption mechanism. The scanning electron microscopy analyses showed that in the presence of the extracts, the surface of the steel is covered by a thin film that allows the sanding marks to be visualized; while without the extracts the surface is rough due to the HCl corrosion effect.

Anticorrosive Performance of Wild Lycium ferocissimum Miers Fruit Extract on Carbon Steel in an Acidic Medium

“…The often well-known acid corrosion inhibitors are organic compounds in which plenty of heteroatoms such as C, N, O, and S were identified to be the main reason for their corrosion inhibition ability. [11][12][13][14] The fundamental principles are based on the selective adsorption of heteroatoms on the metal surface where interactions between nonbinding electrons and or π-electron clouds of the donor atoms to the metal surface form a metal-electrolyte thin film barrier and prevent or slow down corrosion. [2,13] However, most of these inhibitors were expensive, harmful to humankind with a carcinogenic and mutagenic effect, and non biodegradable.…”

“…[11][12][13][14] The fundamental principles are based on the selective adsorption of heteroatoms on the metal surface where interactions between nonbinding electrons and or π-electron clouds of the donor atoms to the metal surface form a metal-electrolyte thin film barrier and prevent or slow down corrosion. [2,13] However, most of these inhibitors were expensive, harmful to humankind with a carcinogenic and mutagenic effect, and non biodegradable. [2,15] To cope with this challenge and to meet the imposed environmental requirements, researchers have prompted the search for eco-friendly anti-corrosion agents as an alternative to organic inhibitors to promote sustainable greenness to the environment and align perfectly with the concept of "green chemistry".…”

“…In fact, from 1960 onward, a variety of anti‐corrosion techniques was employed to protect and halt metals, and alloys from destruction. The often well‐known acid corrosion inhibitors are organic compounds in which plenty of heteroatoms such as C, N, O, and S were identified to be the main reason for their corrosion inhibition ability [11–14] . The fundamental principles are based on the selective adsorption of heteroatoms on the metal surface where interactions between nonbinding electrons and or π‐electron clouds of the donor atoms to the metal surface form a metal‐electrolyte thin film barrier and prevent or slow down corrosion [2,13] .…”

Evaluation of endemic Chilean plant‐based Chañar extract (Geoffroea decorticans) as an inhibitor of corrosion for A36 steel under a saline environment

“…For example, Zhang et al [6] evaluated Idesia fruit extracts as a corrosion inhibitor for copper in a 0.5M sulfuric acid solution; Halambek et al [7] used pectins from tomato peel waste as a corrosion inhibitor for tin in a sodium chloride/ acetic acid solution; Wang et al [8] evaluated the extract of tobacco rob as a scale and corrosion inhibitor in artificial seawater; Vera et al [9] used apple peel waste as a steel corrosion inhibitor in a saline solution, among other authors. [6][7][8][9][10][11][12][13] For this reason, this study obtained an organic inhibitor from natural extracts from the fruit of Geoffroea decorticans, a desert plant endemic to northern Chile commonly known as Chañar, and evaluated its effects against corrosion of carbon steel under a saline environment.…”

“…For example, Zhang et al [6] evaluated Idesia fruit extracts as a corrosion inhibitor for copper in a 0.5M sulfuric acid solution; Halambek et al [7] used pectins from tomato peel waste as a corrosion inhibitor for tin in a sodium chloride/acetic acid solution; Wang et al [8] evaluated the extract of tobacco rob as a scale and corrosion inhibitor in artificial seawater; Vera et al [9] used apple peel waste as a steel corrosion inhibitor in a saline solution, among other authors. [ 6–13 ]…”