Application of Essential Oils as green corrosion inhibitors for metals and alloys in different aggressive mediums

The use of inhibitors for the protection metals and alloys against corrosion in different aggressive environment is one of the best choices. In recent years, essential oils have been explored as green corrosion inhibitors because to their bio-degrability, eco-friendliness, low cost and easy availability. The inhibition performance of these natural products may be to the adsorption, by a synergistic effect, of their different phytochemical constituents including oxygenated monoterpens and sesquiterpens as well as hydrcarbons products. The inhibition effectiveness of these green corrosion inhibitors was evaluated by using numerous techniques like weight loss method, polarization study and AC impedance spectra. The protective layer (film) formed on the metal surface has been analyzed by IR spectroscopy, scanning electron microscopy coupled with EDX and X-ray photoelectron spectroscopy (XPS) techniques. This review presents most of the research work published in recent years on the use of essential oils as green corrosion inhibitors for various metals and alloys in different mediums

Gas Chromatography-Mass Spectrometry Analysis and Comparison of Volatile Components Obtained by Hydrodistillation and Headspace Solid Phase Microextraction (HS-SPME) from Teucrium luteum subsp. flavovirens

The main purpose of this work is to investigate the comparative chemical analysis of essential oil (EO) isolated by hydrodistillation (HD) and volatile fraction (VF) detected by headspace solid-phase micro-extraction (HS–SPME) obtained from Teucrium luteum subsp. flavovirens using Gas Chromatography–Retention Indices (GC-RI) and GC–Mass Spectrometry (GC-MS). 63 volatile compounds identified in hydrodistilled essential oil (HD), representing 89.9% of the total oil, while HS-SPME revealed 50 components constituting 99.3% of the volatile material. The chemical composition of EO comprised mainly of of oxygenated sesquiterpenes (48.6%) while, hydrocarbon monoterpenes were detected in higher concentrations in VF (54.1%). The comparative analysis of two chemoprofiles obtained by two methods shows quantitative and semi-qualitative differences. The current study is the first report involving rapid analysis of volatile components of T. luteum subsp. flavovirens by HS-SPME

Characterization of Lavandula multifida volatile composition from Morocco by headspace solid-phase Microextraction (HS-SPME) and Hydrodistillation coupled to GC–MS

The essential oil and volatiles compounds of Lavandula multifida L., aerial parts collected in South-East Morocco, obtained by hydrodistillation (HD) and headspace solid phase Microextraction (HS-SPME), were analyzed using Gas Chromatography-Flame Ionization Detector (GC-FID) and GC-Mass Spectrometry (GC-MS). 31 components, accounting 94.3% in the total essential oil, were identified by HD and 21 compounds, representing 90.2% of the headspace, were characterized by HS-SPME. The major components identified are carvacrol (57.9% ; 65.6%), carvacrol methyl ether (7.6% ; 4.6%), p-cymen-8-ol (3.9% ; 4.8%) and spathulenol (3.8% ; 8.6%) of essential oil and volatile compounds detected in HS-SPME, respectively. By comparison of HD and HS-SPME extraction, only quantitative differences of some components can be observed in both aromatic profiles, while qualitatively are rather similar. This study demonstrates that HD and HS-SPME modes could be complimentary extraction techniques in order to obtain the complete characterization of plant volatiles

Comparative chemical analysis of volatile compounds of Warionia saharea leaves using hydrodistillation and headspace solid-phase microextraction (HS-SPME)

The objective of this study is to report the comparative chemical analysis of essential oil (EO) obtained by hydrodistillation (HD) and volatile fraction (VF) detected by headspace solid-phase micro-extraction (HS–SPME) isolated from Warionia saharea leaves using Gas Chromatography–Retention Indices (GC-RI) and GC–Mass Spectrometry (GC-MS). 39 volatile compounds identified in hydrodistilled essential oil (HD), representing 92.7% of the total oil, while HS-SPME revealed 25 components constituting 94.1% of the volatile material. The chemical composition of the HS-SPME and HD extract comprised mainly of phenylpropanoids (36.9%) and oxygenated sesquiterpenes (52.8%), respectively. The comparative analysis of two chemoprofiles obtained by two methods shows both qualitative as well as quantitative differences. The current study is the first report involving rapid analysis of volatile components of W. saharea by HS-SPME

Synthesis, Characterization and Corrosion Inhibition Potential of Olefin Derivatives for Carbon Steel in 1M HCl: Electrochemical and DFT Investigations

This research aims to evaluate the anticorrosive properties of three olefins derivatives synthesized by the microwave oven technique in a dry environment. These olefins have been identified using different analytical methods, including NMR, IR and XRD. The corrosion inhibition of these compounds for carbon steel in 1 M HCl solution was studied using potentiodynamic polarization (PDP) curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). The experimental results show that the tested compounds are good corrosion inhibitors for steel in an acidic media. Furthermore, the inhibition efficiency increased with increasing inhibitor concentration and decreased with increasing temperature. The PDP study showed the mixed type nature of these inhibitors, whereas thermodynamic parameters suggested that their adsorption obeys the Langmuir isotherm model. The EIS measurements revealed that the corrosion of the steel is produced by a single mechanism, which is charge transfer. SEM with EDX analysis confirmed the protection of the steel surface by the adsorption of the inhibitors. The relationship between the electronic properties of the inhibitors and the protective ability was further discussed using DFT calculations. Both experimental and theoretical results are well compatible and complement each other well

Assessment of the Corrosion Inhibition Ability of Eucalyptus globulus Leaf Extract Essential Oil on C24 Steel in a 1M HCl Environment

This study examined the properties of the essential oil of Eucalyptus globulus, an aromatic plant present in Senegal. The essential oil was extracted by hydrodistillation and analyzed by usual gas chromatography (GC/Ir and GC/MS). The main chemical compounds identified were eucalyptol (40.42%), α-phellandrene (8.92%), limonene (7.17%), and α-pinene (6.49%). The inhibitory effect of this essential oil on C24 steel in 1M HCl medium was also evaluated using electrochemical methods. The results indicated a maximum effectiveness of 80.6% at an essential oil concentration of 1.5 g/L and a temperature of 290 K. Beyond this concentration, the effectiveness decreased. We also examined the influence of temperature on the inhibitory action of the essential oil, in a range from 290 to 328 K. We found a decrease in effectiveness with increasing temperature, reaching 48.67% at 328 K. In addition, the thermodynamic quantities were calculated. The isotherm results demonstrated that the adsorption of the essential oil follows the Langmuir isotherm, suggesting a physical adsorption character of this essential oil on the C24 steel