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To evaluate the effect of natural rosemary oil as non toxic inhibitor on the corrosion of steel in H₃PO₄ media at various temperatures.

The oil was hydro‐distilled. The oil was used as inhibitor in various corrosion tests. Gravimetric and electrochemical techniques were used to characterise the corrosion mechanism.

Chromatographic analysis by GC showed that the oil was rich in 1,8‐cineole. The oil was a good inhibitor. But, its efficiency decreased with temperature.

The inhibition efficiency increased with the concentration of the natural oil to attain 73 per cent at 10 g/l. Good agreement between the various methods explored was observed. Polarisation measurements showed that rosemary oil acted essentially as a cathodic inhibitor.

The efficiency of the oil increased with the concentration but decreased with the rise of temperature in the 298‐348 K range. The natural oil could thus be used in chemical cleaning and pickling processes.

The originality of this work is the finding of a safe and cheap inhibitor from natural plants.

To evaluate the effect of synthesised calixarenes as new inhibitors on the corrosion of steel in HCl media at various temperatures.

Calixarenes have been synthesised and tested as corrosion inhibitors. Gravimetric technique and potentiodynamic polarisation and impedance spectroscopy methods were used.

Calixarenes exhibited a good inhibition. Their efficiency decreases slightly with temperature.

It was found that the inhibition efficiency increases with the concentration of inhibitors to reach 92 per cent at 10⁻⁴M.

The efficiency of calixarene derivatives increases with the concentration and falls slowly with temperature to attain 84 per cent at 353 K range. Calixarenes can be used in chemical cleaning and pickling processes.

The originality of this work is to find an inhibitor to give protection close to 100 per cent.

The purpose of this paper is to evaluate the corrosion inhibition potential of mangrove (Rhizopora apiculata) tannin in hydrochloric acid medium on copper with the view of developing a natural corrosion inhibitor.

The mangrove tannin was extracted from the mangrove bark and its anticorrosion potential was studied by weight loss, electrochemical and scanning electron microscopy (SEM) analysis.

It has been found that the mangrove tannin effectively inhibits the corrosion on copper metal in hydrochloric acid solution. The results of the electrochemical and weight loss methods showed that the inhibition efficiency of mangrove tannin increases with increasing its concentration. Inhibition is achieved through the adsorption of tannin molecules onto the copper surface and the adsorption follows the Langmuir adsorption isotherm model. SEM study also supports the adsorption of the inhibitor molecules onto the copper surface.

In this paper, mangrove tannin has been studied for the first time as a potential copper corrosion inhibitor in hydrochloric acid medium. The anticorrosion effect of tannin has been proven by standard methods. This natural inhibitor could find use in industries where copper is used as a fabrication metal.

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 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.

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.

This paper aims to evaluate in vitro antibacterial activity of oregano essential oil against foodborne pathogens as a starting point for the use of spice as a natural preservative in food.

Disc and well‐diffusion assays were performed to investigate antibacterial activity of oregano essential oil against six bacteria strains: Bacillus cereus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella Typhimurium. Three concentrations of oregano essential oil were employed: 1.0 percent, 2.0 percent and 5.0 percent. Bacterial growth inhibition was determinate as the diameter of the inhibition zones.

Oregano essential oil showed antibacterial activity against spoilage microorganisms, at different concentrations, except for P. aeruginosa. There was a significant difference between methodologies only for the microorganism S. aureus. The results provided evidence of the existence of significant differences among the concentrations of oregano essential oil for each microorganism evaluated.

Although the research for this paper involved only oregano essential oil, it provided a starting‐point for further investigations concerning spices as natural preservatives for food systems.

Disc and well‐assays were found to be simple and reproducible practical methods. Other spices, their essential oil and extracts might be researched against other micro‐organisms. Furthermore, in situ studies need to be performed to evaluate possible interactions between essential oils and compounds naturally present in food against microbial strains.

The imminent adoption of measures to reduce the use of additives in foods and the reduction on using such compounds.

This study provides insights that suggest a promising exploratory development of food natural preservative against spoilage microorganisms in food systems by the use of oregano essential oil.

To evaluate the effect of different parts of Carica papaya (leaves (LV), seeds (SD), heart wood (HW) and bark (BK)) as eco‐friendly and non‐toxic mild‐steel corrosion inhibitors in H₂SO₄ at 30 to 60 ^oC.

Acid extracts of the different parts of Carica papaya were used as inhibitors in various corrosion tests. Gravimetric and gasometric techniques were used to characterise the mechanism of inhibition.

The LV, SD, HW and BK extracts were found to inhibit mild steel corrosion in H₂SO₄. The inhibition efficiencies of the plant's part extracts follow the trend: LV > SD > HW > BK. Inhibition efficiency increased with extracts concentration but decreased with temperature. Physical adsorption of the phytochemical components of the plant on the metal surface is proposed as the mechanism of inhibition. The experimental data fits well into the Langmuir and Temkin adsorption isotherms.

The plant extracts can be used in chemical cleaning and picking processes.

The research provides information on the possible use of the different parts of Carica papaya as sources of cheap eco‐friendly and non‐toxic corrosion inhibitors.

This study aims to investigation of the guar gum-manganese dioxide (GG/MnO₂) nanocomposite (NC) synthesized using an environment-friendly method and the degradation of reactive yellow (RY 145) dye in the UV system.

Characterization of the GG/MnO₂ NCs were conducted using field emission scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. Experiments were conducted using a 1 L glass reactor coupled with Ultraviolet (UV-C) blue light bulb of wavelength 250 nm and power of 8 W.

The NC (2.25 g/L) displayed high RY 145 dye degradation (81%) with 10 mg/L of concentration at pH 3. The coefficient of determination (R² 0.99) also depicted that the model fits the experimental data. The analysis of variance (ANOVA) showed that the F-values of 464.75, 276.04 and 5.15 are related to the dose of GG/MnO₂ NCs, initial concentration of RY 145 dye and solution pH, respectively.

The GG/MnO₂ NCs followed by photo oxidation process (UV-process) could be used to degrade the RY 145 dye from synthetic wastewater.

There are two main innovations. One is that the novel process is performed successfully for RY 145 dye degradation. The other is that the optimized conditions are obtained by Box–Behnken design. Also, the effects of different variables on the RY 145 dye removal efficiency were investigated.

Corrosion inhibitors most commonly are used in the acid pickling, cleaning and etching solutions. Plant extracts as rich and cheap resources are among the eco-friendly inhibitors. This study aims to investigate the inhibition effect of plantain extract on mild steel corrosion.

The inhibition influence of plantain extract on mild steel corrosion was investigated through Tafel polarization, electrochemical impedance spectroscopy and weight loss techniques in 1 M HCl solution. Furthermore, the sample surface morphology was verified by scanning electron microscopy.

The inhibition effect of the plantain extract was increased with the increase in the inhibitor concentration due to its adsorption on the surface of samples. The adsorption mechanism of the plantain extract on mild steel is physical adsorption and follows Langmuir isotherm.

The results obtained from different methods showed that the plantain extract has good inhibition performance on corrosion mild steel in 1 M HCl solution as a green inhibitor.