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The purpose of this paper is to test bagasse extract as an effective corrosion inhibitor.

The bagasse was extracted without any toxic substance and was found to be effective for corrosion of J55 steel.

The inhibition efficiency of bagasse was more than 90 per cent in 3.5 per cent NaCl solution saturated with CO₂ for corrosion inhibition of J55 steel.

The inhibition effect of Saccharum sinense bagasse extract on the corrosion of J55 steel in 3.5 weight per cent NaCl saturated with CO₂ solution was investigated by means of Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, polarization curve and scanning electron microscope.

It can be used as low-cost corrosion inhibitor.

It is an environment-friendly corrosion inhibitor.

This work is original and carried out in Southwest Petroleum University, China. This is not communicated anywhere else.

To determine the inhibition efficiency and adsorption characteristics of two water soluble polymers namely polyvinyl alcohol (PVA) and polyethyleneglycol (PGE) as corrosion inhibitors of mild steel in H₂SO₄.

The inhibition efficiencies of PVA and PEG were evaluated using the weight loss and hydrogen evolution techniques at 30‐60°C.

The inhibition efficiency (I per cent) of the inhibitors increased with increase in concentration and temperature. The inhibitors (PVA and PEG) were found to obey Temkin, Freundlich and Langmuir adsorption isotherms from the fit of the experimental data at all concentrations and temperatures studied. The phenomenon of chemical adsorption is proposed from the activation parameters obtained. PEG was found to be a better inhibitor than PVA.

The mechanistic aspect of the corrosion inhibition can be better understood using electrochemical studies such as polarization and AC impedance spectra.

The findings may be useful in cooling water systems in industries under simulated conditions.

This paper provides additional new information on the inhibiting characteristics of PVA and PEG as promising corrosion inhibitors.

This paper aims to investigate the inhibitive effect of ethanol extracts of Garcinia kola (EXG) for the corrosion of mild steel in H₂SO₄ solutions. The study is another trial to find a cheap and environmentally safe inhibitor for mild steel corrosion.

The inhibition efficiency has been evaluated using the hydrogen evolution technique at 30‐60°C. The mechanism of adsorption inhibition and type of adsorption isotherm were proposed based on the trend of inhibition efficiency and kinetic data.

The results obtained indicate that EXG inhibits the corrosion of mild steel in acidic medium and that the inhibition efficiency increases with an increase in the concentration of ethanol extracts and decreasing temperature. The inhibition efficiency increased on addition of potassium iodide to EXG, indicating synergism. The experimental data obeyed the Langmuir adsorption isotherm as well as the El‐Awady et al. thermodynamic‐kinetic model. The activation energy of inhibition of 6.8508 KJ/mol calculated for the corrosion process suggests that the EXG molecules are physically adsorbed on the metal surface.

Further investigations involving electrochemical studies such as polarization method will provide further enlightenment on the mechanistic aspect of the corrosion inhibition.

This paper provides new information on the possible application of EXG as an environmentally friendly corrosion inhibitor under the specified conditions. This environmentally friendly inhibitor could find possible applications in metal surface anodizing and surface coatings.

To investigate the inhibitive effect of gum arabic (GA) for the corrosion of aluminium in alkaline (NaOH) medium and determine its adsorption characteristics. The present work is another trial to find a cheap and environmentally safe inhibitor for aluminium corrosion.

The inhibition efficiency (%I) has been evaluated using the hydrogen evolution (via the gasometric assembly) and the thermometric methods at 30 and 40°C. The concentrations of GA (inhibitor) used were 0.1‐0.5 g/l and the concentrations of NaOH (the corrodent) were 0.1‐2.5 M. The mechanism of adsorption inhibition and type of adsorption isotherms were proposed from the trend of inhibition efficiency with temperature, E_a, ΔG_ads and Q_ads values.

GA inhibited the corrosion of aluminium in NaOH solutions. The inhibition efficiency increased with increase in GA concentration and with increase in temperature. Phenomenon of chemical adsorption is proposed for the inhibition and the process followed the Langmuir and Freundlich adsorption isotherms. The results obtained in this study for the %I were comparable for the two methods used and were corroborated by kinetic and thermodynamic parameters evaluated from the experimental data.

Further investigations involving electrochemical studies such as polarization method will enlighten more on the mechanistic aspect of the corrosion inhibition.

This paper provides new information on the possible application of GA as an environmentally friendly corrosion inhibitor even in highly aggressive alkaline environments. It has not been published elsewhere.

To investigate the effect of halide ions on the corrosion inhibition of mild steel using polyvinyl alcohol (PVA) in H₂SO₄ at 30‐60°C and to study the mechanism of action.

The corrosion rates were determined using the gravimetric (weight loss) and gasometric (hydrogen evolution) techniques. The results obtained in the absence and presence of PVA, halides, PVA – halides combination were used to calculate the inhibition efficiency (%I), degree of surface coverage and to propose the mechanism of inhibition and type of adsorption.

Results obtained showed that inhibition efficiency (%I) increased with the increase in concentration of PVA, on the addition of halides and with the increase in temperature. Phenomenon of chemical adsorption was proposed and PVA was found to obey Langmuir, Flory‐Huggins and Freundlich adsorption isotherms. The synergism parameter, S₁, evaluated was found to be greater than unity and the values of E_a, ΔH°, ΔS° and ΔG° obtained revealed that the adsorption process was spontaneous.

Electrochemical studies such as polarization and AC impedance spectra will enlighten more on the mechanistic aspects of the corrosion inhibition and more polymers need to be evaluated as corrosion inhibitors.

PVA can be used as corrosion inhibitor and the addition of halides to PVA improves the inhibition efficiency considerably.

This paper provides new information on the effects of halides on the corrosion inhibition using PVA as an inhibitor for mild steel in acidic medium. Such a study had not been reported elsewhere.

To investigate the inhibitive effect of Delonix regia extracts to reduce the corrosion rate of aluminium in acidic media. The study was a trial to find a low cost and environmentally safe inhibitor to reduce the corrosion rate of aluminium.

The inhibition efficiency was evaluated using the hydrogen evolution technique at 30°C. The mechanism of adsorption inhibition and type of adsorption isotherm was characterised from trends of inhibition efficiency and kinetic data.

Delonix regia extracts inhibited the corrosion of aluminium in hydrochloric acid solutions. The inhibition efficiency increased with increasing concentration of the inhibitor but decreased with increase in exposure time. The acid extracts (hydrochloric acid seeds extract (HSE) and hydrochloric acid leaf extract (HLE)) were found to be more effective than the ethanolic extracts (ethanol seeds extract (ASE) and ethanol leaves extract (ALE)) and the inhibition followed the order: HSE (93.6 per cent) > HLE (83.5 per cent) > ASE (63.9 per cent) > ALE (60.4 per cent). The low negative values of ΔG_ad: −20.14 kJ mol⁻¹ for HSE, −18.08 kJ mol⁻¹ for HLE, −15.96 kJ mol⁻¹ for ASE and −15.12 kJ mol⁻¹ for ALE, as calculated from the Langmuir isotherm, indicated that the inhibitor molecules adsorbed onto aluminium by a physiosorption‐based mechanism. A first‐order type of reaction mechanism was obtained from the kinetic treatment of the H₂ gas evolution data.

Further investigations involving electrochemical studies such as polarization method should shed further light on the mechanistic aspects of the corrosion inhibition.

This paper provides new information on the possible application of Delonix regia as an environmentally friendly corrosion inhibitor under the specified conditions. This environmentally friendly inhibitor could find possible applications in metal surface anodizing and surface coatings.

Corrosion is a major concern for many industries that use metals as structural or functional materials, and the use of corrosion inhibitors is a widely accepted strategy to protect metals from deterioration in corrosive environments. Moreover, the toxic nature, non-biodegradability and price of most conventional corrosion inhibitors have encouraged the application of greener and more sustainable options, with natural and synthetic drugs being major actors. Hence, this paper aims to stress the capability of natural and synthetic drugs as manageable and sustainable, environmentally friendly solutions to the problem of metal corrosion.

In this review, the recent developments in the use of natural and synthetic drugs as corrosion inhibitors are explored in detail to highlight the key advancements and drawbacks towards the advantageous utilization of drugs as corrosion inhibitors.

Corrosion is a critical issue in numerous modern applications, and conventional strategies of corrosion inhibition include the use of toxic and environmentally harmful chemicals. As greener alternatives, natural compounds like plant extracts, essential oils and biopolymers, as well as synthetic drugs, are highlighted in this review. In addition, the advantages and disadvantages of these compounds, as well as their effectiveness in preventing corrosion, are discussed in the review.

This survey stresses on the most recent abilities of natural and synthetic drugs as viable and sustainable, environmentally friendly solutions to the problem of metal corrosion, thus expanding the general knowledge of green corrosion inhibitors.

This study aims to synthesize two organic heterocyclic compounds, (2E,3E)-6-chloro-2,3-dihydrazinylidene-1-methyl-1,2,3,4-tetrahydroquinoxaline (MR1) and (2E,3E)-2,3-dihydrazinylidene-1-methyl-1,2,3,4-tetrahydroquinoxaline (MR2), characterize them using nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR) and evaluate their effectiveness as corrosion inhibitors in an acidic environment (15% HCl).

The synthesized compounds, MR1 and MR2, were tested for their corrosion inhibition properties using potentiodynamic polarization and electrochemical impedance spectroscopy. Post-corrosion, the steel surface was analyzed with scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) to confirm the adsorption of the compounds. The experimental findings were further supported by density functional theory calculations and molecular dynamics simulations.

The results indicated that both MR1 and MR2 exhibit significant anticorrosive activity in a 15% HCl environment. The analyses performed with SEM, EDX and AFM confirmed the effective adsorption of the inhibitors on the steel surface, forming a protective layer. Theoretical studies provided additional insights into the adsorption mechanisms and stability of the inhibitors.

This work introduces novel organic heterocyclic compounds based on quinoxalinone as effective corrosion inhibitors in acidic environments. The combined experimental and theoretical approach provides a comprehensive understanding of their anticorrosive behavior.

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.

In line with current research efforts to develop eco-friendly strategies for corrosion mitigation, the purpose of this study is to appraise the anti-corrosion potential of selected amino acids on magnesium corrosion in sodium chloride solutions.

The corrosion inhibition of magnesium in aqueous solutions in the presence of benign, eco-friendly and readily available amino acids (alanine, arginine, histidine, lysine, proline) were evaluated using electrochemical methods.

Amino acids suppressed magnesium corrosion rate in aqueous sodium chloride solutions. The order of inhibition efficiency (%IE) was as follows: alanine < arginine < histidine < lysine < proline. The open circuit potential shift with respect to the blank was less than 0.085 V_SCE, indicating that the amino acids are mixed-type corrosion inhibitors. In addition, the %IE of the amino acids was inversely proportional to the molecular weight. The results obtained indicate that the amino acids can serve as sustainable eco-friendly corrosion inhibitors for magnesium with the best inhibition efficiency attributed to proline with an efficiency of 85.1%.

New information on the application of amino acids as green sustainable corrosion inhibitors is provided herein.