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The purpose of this paper is to study the inhibitive and adsorptive characteristics of ethanol extract of Heinsia crinata for the corrosion of mild steel in H₂SO₄ solutions.

The inhibition efficiencies were evaluated using weight loss, thermometric and hydrogen evolution techniques while adsorption properties were studied using IR spectroscopy.

The inhibition efficiency of ethanol extract of Heinsia crinata varies with concentration of the extract, period of immersion and with temperature. The extract acts as an adsorption inhibitor because of its phytochemical composition. The extract is adsorbed spontaneously on the surface of mild steel according to Temkin and Frumkin adsorption isotherms. The mechanism of physical adsorption is proposed from the trend of the inhibition efficiency with temperature and the values of some kinetic and thermodynamic parameters obtained.

The paper provides information on the use of ethanol extract of Heinsia crinata as a corrosion inhibitor. Electrochemical studies such as polarisation and AC impedance spectra will throw more light on the mechanistic aspects of the corrosion inhibition.

Ethanol extract of Heinsia crinata can be used as an environmentally friendly inhibitor for the corrosion of mild steel in H₂SO₄. This environmentally friendly inhibitor could find possible applications in metal surface anodising and surface coatings.

The paper provides information on an environmentally‐friendly corrosion inhibitor.

The purpose of this paper is to study the effect of concentration of H₂SO₄ on the corrosion of mild steel and to investigate the inhibitive properties of Aloe vera for mild steel corrosion. The study also seeks to investigate the possibility of using Aloe vera as a green corrosion inhibitor for mild steel.

Gasometric (Hydrogen evolution) and thermometric methods of corrosion monitoring have been adopted for the study. The study was conducted at 303 and 333 K and the concentrations of inhibitor used were 0.1, 0.2, 0.3 and 0.4 g/L. The inhibitor was prepared by using alcohol extract of moisture free samples of Aloe vera. The functional groups present in the extract have been determined using infra red spectrophotometer. Thermodynamic and adsorption theories have been used to interpret the data.

Ethanol extract of Aloe vera is a good inhibitor for mild steel corrosion at 303 and 333 K. The inhibitor acts by chemical adsorption isotherm. Functional groups identified in the extract are found to played dominant role in the adsorptive and inhibitive potentials of this extract. Values of inhibition efficiency obtained from gasometric and thermometric analysis were comparable.

Further study on synergism with the view of enhancing the inhibition efficiency of Aloe vera extract and the used of other analytical methods may reveals a wealth of information on the possibilities of transforming this research for field application.

The paper provides information on the use of Aloe vera as a green corrosion inhibitor. It has not been published elsewhere.

The aim of this paper is to appraise the inhibiting potential of hydroxypropyl methylcellulose (HPMC) on the corrosion of mild steel and aluminium in sulphuric and hydrochloric acid solutions.

The effects of two different corrodents on the dissolution of mild steel and aluminium were examined. Corrosion rates were determined using the weight loss technique. Inhibition efficiency was estimated by comparing the corrosion rates in absence and presence of the additive. The kinetics and mechanism of HPMC adsorption were investigated by impedance study while the anodic and cathodic partial reactions were studied by polarization measurements.

The results reveal that corrosion rate of mild steel and aluminium decreased with addition of HPMC. The corrosion rate and inhibition efficiency were found to depend on the concentration of the inhibitor. The polarization data indicated that the inhibitor was of mixed-type, with predominant effect on the cathodic partial reaction. electrochemical impedance spectroscopy confirms that corrosion inhibition was by adsorption on the metal surface following Freundlich adsorption isotherm via physisorption mechanism.

Hydroxypropyl methylcellulose has been studied for the first time as an inhibitor of mild steel and aluminium corrosion and the results suggest that the inhibitor could find practical applications in corrosion control in HCl and H₂SO₄ acid media. The findings are particularly useful, considering the fact that HPMC is a good film former and viscosity enhancer which could also be used in paint formulation.

The purpose of this paper is to study the inhibitive and adsorption characteristics of ethanol extract of Garcinia kola and Cola nitida for the corrosion of mild steel in H₂SO₄ solutions.

The inhibition efficiencies were evaluated using weight loss and thermometric methods while the adsorption properties were studied using IR spectroscopy.

The inhibition efficiencies of ethanol extracts of Garcinia kola and Cola nitida were comparable and vary with concentration of the extract, period of immersion and with temperature. The extracts act as adsorption inhibitors because of its phytochemical composition. The extracts are adsorbed spontaneously on the surface of mild steel according to Langmuir adsorption isotherms. The mechanism of physical adsorption is proposed from the trend of the inhibition efficiency with temperature and the values of activation energy and some thermodynamic parameters obtained.

The study provides information on the use of ethanol extract of Garcinia kola and Cola nitida as corrosion inhibitors for mild steel. Electrochemical studies such as polarisation and AC impedance spectra will illuminate the mechanistic aspects of the extract.

Ethanol extract of Garcinia kola and Cola nitida are environmentally friendly inhibitors for the corrosion of mild steel in H₂SO₄.

These environmentally friendly inhibitors may find possible applications in metal surface anodising and surface coatings.

The purpose of this paper is to develop an eco-friendly corrosion inhibitor for mild steel in 1 M HCl.

A pharmaceutical drug acetyl G was investigated for its corrosion inhibition efficiency using weight loss method, potentiodynamic polarisation and electrochemical impedance spectroscopy.

The inhibition efficiency increased with increase in inhibitor concentration. Results from polarisation studies revealed mixed type of inhibition. Impedance studies, scanning electron microscopy and Fourier transform spectroscopy confirm the adsorption of inhibitor on the mild steel surface.

The drug acetyl G has sulphur and nitrogen atoms which effectively block the corrosion of mild steel and is non-toxic and has good inhibition efficiency.

This method provides an excellent, non-toxic and cost-effective material as a corrosion inhibitor for mild steel in acid medium.

Application of this drug as a corrosion inhibitor has not been reported yet in the literature. Replacing the organic inhibitors, this green inhibitor shows excellent inhibition efficiency. This is adsorbed excellently on the mild steel surface due to the presence of long chain and hetero atoms. Thus, the drug retards the corrosion reaction.

The paper aims to investigate the effectiveness of hydroxypropyl methylcellulose (HPMC) as corrosion inhibitor for aluminium in 0.5 M H₂SO₄ solution.

This study was carried out using weight loss and electrochemical techniques. Inhibition efficiency was determined by comparing the corrosion rates in the absence and presence of inhibitor system. Quantum chemical computations were performed using density functional theory to assess the parameters responsible for the inhibition process and also to analyse the local reactivity of the molecule.

HPMC inhibited aluminium corrosion in the acidic environment. The inhibition efficiency was found to depend on concentration of the inhibitor. Impedance results reveal that HPMC is adsorbed on the corroding metal surface. Polarization results show that the dissolution reaction is due to destabilization of the passive oxide film on the Al surface. Adsorption of the inhibitor is approximated by Freundlich adsorption isotherm and the calculated standard free energy of adsorption indicates weak physical interaction between the inhibitor molecules and aluminium surface. This can be attributed to preferential interaction of the active sites with the passive oxide layer. The calculated quantum chemical parameters show good correlation with the inhibition efficiency.

HPMC could find possible application as a polymeric thickener and additive to improve corrosion resistance and barrier properties of anticorrosion paints.

This paper provides novel information on the inhibitive characteristics of HPMC under the stated conditions. The inhibitor systems provide an effective means for suppressing aluminium corrosion even in highly aggressive acidic environments.

The purpose of this investigation is to study the corrosion inhibition of carbon steel (CS) using a “green” inhibitor, Opuntia ficus-indica, in an aerated, 0.5 M H₂SO₄ solution at different concentrations and temperatures.

Weight loss determinations, surface studies, electrochemical impedance spectroscopy and potentiodynamic polarization were applied during the investigation.

It was observed that Opuntia ficus-indica extract can decrease the corrosion rate of CS, and its efficiency increases with increasing concentration up to 1,000 ppm and with time, but decreases with increasing the temperature from 25 to 600C. The inhibitory activity is due to the presence of phenolic compounds in its chemical structure.

The work was done under static conditions, whereas in acid cleaning conditions, there is a dynamic system. However, the findings may apply to both the systems.

CS is used in acidic environments in the acid cleaning industry.

Results of this work show that it is possible to reduce the cost of repair of equipment and the environmental impact of corrosion.

There are very few investigations on the study of Opuntia ficus-indica leaf extract as a green inhibitor in an acidic environment.

Plant development and use as green corrosion inhibitors are already recognized as one of the most environmentally friendly and effective protocols. In recent years, efforts have been made to find green corrosion inhibitors as an alternative to synthetic inhibitors for metals in acid medium. This paper aims to report the investigation of use of aqueous extracts of Tamarindus Indica as green inhibitors for corrosion of metals within different circumstances.

The use of Tamarindus Indica extracts (leaves, stem, fruit pulp and fruit husk) as corrosion inhibitors for mild steel and aluminum in different mediums (HCl, H2SO4, formic acid and citric acid) at different temperatures was investigated.

The inhibitory efficiency of Tamarindus Indica extracts increases with increasing concentration and decreases with increasing temperature. Langmuir is the adsorption isotherm, and the extract (inhibitor) is a mixed-type inhibitor (physisorption and chemisorption).

Tamarindus extracts (leaves, stem, fruit pulp and fruit husk) are effective inhibitors and can be used to protect metals from corrosion at different circumstances.

To the best of the authors’ knowledge, this is the first review that discusses the use of Tamarindus Indica extracts as corrosion inhibitors for metals.

The purpose of this study is to understand the inhibitor behavior of specific drug against mild steel corrosion and their adsorption mechanism on the surface.

Corrosion rates are influenced by the formation of inhibitor aggregates at the mild steel surface. Detail surface characterizations of mild steel have been studied before and after adsorption of drugs in 1N HCl solution. Scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy were used to examine the effect of drug adsorption on steel surface.

Scanning electron microscopy analysis suggested that the metal had been protected from aggressive corrosion because of the addition of the inhibitors. Atomic force microscopy visualization confirmed the formation of protective layer on steel surface, resulting in the decrease in surface roughness with corrosion rates. The nature of metal surface has been analyzed by Fourier transform infrared spectroscopy.

The findings of this study will help us to understand the interaction of specific drugs with mild steel surface and their potential inhibition mechanism.

The purpose of this paper is to study the inhibitive and adsorptive characteristics of ethanol extract of Gongronema latifolium (GL) as a corrosion inhibitor for mild steel in H₂SO₄.

The inhibition efficiencies were evaluated using thermometric and hydrogen evolution techniques.

The inhibition efficiency of ethanol extract of GL vary with concentration of the extract, period of immersion and with temperature. The extract acts as an inhibitor because of its phytochemical and amino acid composition. The extract is adsorbed spontaneously on the surface of mild steel according to Langmuir adsorption isotherm. The mechanism of physical adsorption is proposed from the trend of the inhibition efficiency with temperature and the values of some kinetic and thermodynamic parameters obtained.

The study provides information on the use of ethanol extract of GL as a corrosion inhibitor. Electrochemical studies such as polarisation and alternating current impedance spectra will throw more light on the mechanistic aspects of the corrosion inhibition.

Ethanol extract of GL can be used as an environmentally friendly inhibitor for the corrosion of mild steel in H₂SO₄.

This environmentally friendly inhibitor could find possible applications in metal surface anodising and surface coatings.