An-Najah Staff

The inhibition effect of ylang-ylang oil (YYO) and their adsorption on carbon steel surface in hydrochloric acid was realized at temperatures varying between 308 and 338 K by weight loss, EIS, and potentiodynamic polarization techniques. The tested compound showed inhibition efficiency that is superior 87 % for a concentration equal to 1.0 g/L. Polarization measurements indicate that the examined oil act as a mixed inhibitor with predominant anodic effectiveness and the protection efficiency increases with inhibitor concentration but this effect decreased with increasing of temperature. Data obtained from EIS studies were analyzed to model inhibition process through appropriate equivalent circuit models. The adsorption of YYO on carbon steel surface obeys Langmuir adsorption isotherm in acid medium and the activation were determined and discussed.

There is a growing trend in utilizing plant extracts and pharmaceutical compounds as corrosion inhibitors. Accurate identification of the essential oil of aerial parts of Pelargonium was obtained using hydrodistillation, gas chromatography and gas chromatography–mass spectrometry. The oil was predominated by citronellol (22.8 %). The inhibitory effect of essential oil and extract of Pelargonium was estimated on the corrosion of mild steel in 1 M hydrochloric acid (HCl) using weight loss, electrochemical impedance spectroscopy (EIS) and Tafel polarization curves. Inhibition was found to increase with increasing concentration of the essential oil and extract of Pelargonium. The effect of temperature on the corrosion behavior of mild steel in 1 M HCl with addition of essential oil and extract was also studied, and the thermodynamic parameters were determined and discussed. Values of inhibition efficiency were calculated from weight loss, Tafel polarization curves, and EIS. All results are in good agreement. Polarization curves showed that essential oil and extract of Pelargonium behave as mixed type inhibitors in HCl (1 M). The results obtained showed that the essential oil and extract of Pelargonium could serve as an effective inhibitor of the corrosion of mild steel in HCl solution. To avoid any unexpected toxicity, the majority of compounds have been studied by using POM analyses. 

The inhibitive action of Hydroxylammonium sulfate ((NH3OH)2SO4) (HAS) on corrosion inhibition of carbon steel (CS) in 1M HCl was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and effect of temperature. The measurements show that inhibition efficiencies increases with increasing of HAS concentrations but decreases with increasing temperatures. This reveals that inhibitive action of inhibitor was mainly due to adsorption on the carbon steel surface and blocked the active sites. The above results showed that HAS acted as a mixed-type corrosion inhibitor. The adsorption of HAS on the carbon steel surface obeyed the Langmuir adsorption isotherm. This was supported by the impedance measurements which showed a change in the charge transfer resistance and double layer capacitance indicating adsorption of HAS on the carbon steel surface. Thermodynamic parameters of studied inhibitor were calculated and discused.

There is a growing trend in utilizing plant extracts and pharmaceutical compounds as corrosion inhibitors. Accurate identification of the essential oil of aerial parts of Pelargonium was obtained using hydrodistillation, gas chromatography and gas chromatography–mass spectrometry. The oil was predominated by citronellol (22.8 %). The inhibitory effect of essential oil and extract of Pelargonium was estimated on the corrosion of mild steel in 1 M hydrochloric acid (HCl) using weight loss, electrochemical impedance spectroscopy (EIS) and Tafel polarization curves. Inhibition was found to increase with increasing concentration of the essential oil and extract of Pelargonium. The effect of temperature on the corrosion behavior of mild steel in 1 M HCl with addition of essential oil and extract was also studied, and the thermodynamic parameters were determined and discussed. Values of inhibition efficiency were calculated from weight loss, Tafel polarization curves, and EIS. All results are in good agreement. Polarization curves showed that essential oil and extract of Pelargonium behave as mixed type inhibitors in HCl (1 M). The results obtained showed that the essential oil and extract of Pelargonium could serve as an effective inhibitor of the corrosion of mild steel in HCl solution. To avoid any unexpected toxicity, the majority of compounds have been studied by using POM analyses.

There is a growing trend in utilizing plant extracts and pharmaceutical compounds as corrosion inhibitors. Accurate identification of the essential oil of aerial parts of Pelargonium was obtained using hydrodistillation, gas chromatography and gas chromatography–mass spectrometry. The oil was predominated by citronellol (22.8 %). The inhibitory effect of essential oil and extract of Pelargonium was estimated on the corrosion of mild steel in 1 M hydrochloric acid (HCl) using weight loss, electrochemical impedance spectroscopy (EIS) and Tafel polarization curves. Inhibition was found to increase with increasing concentration of the essential oil and extract of Pelargonium. The effect of temperature on the corrosion behavior of mild steel in 1 M HCl with addition of essential oil and extract was also studied, and the thermodynamic parameters were determined and discussed. Values of inhibition efficiency were calculated from weight loss, Tafel polarization curves, and EIS. All results are in good agreement. Polarization curves showed that essential oil and extract of Pelargonium behave as mixed type inhibitors in HCl (1 M). The results obtained showed that the essential oil and extract of Pelargonium could serve as an effective inhibitor of the corrosion of mild steel in HCl solution. To avoid any unexpected toxicity, the majority of compounds have been studied by using POM analyses.

2Z)-1-(4-chlorophenyl)-2-[(3E)-3-[2-(4-chloropheny l)-2-oxoethylidene]-3,4dihydro quinoxalin- 2 (1H)-ylidene]ethanone (Q4) was tested as inhibito r for the corrosion of copper in 2M HNO 3 using gravimetric method at 303 – 343 K. The inhibi tor (Q4) showed about 90% inhibition efficiency (E (%)) at an optimum concentration of 1 0 -3 M. The inhibition efficiency increases with increase in inhibitor concentration but decrease wi th rise in temperature. Various parameters (Ea , ∆G ° ads , K ads ) for adsorption reveal a strong interaction betwee n inhibitor and copper surface. The negative values of ∆G° ads indicate the spontaneous adsorption of the inhibit or on copper surface. Kinetic parameters activation such as a E , aH °∆ , aS °∆ and pre-exponential factor have been calculated and discussed. Further, theore tical calculations were carried out and relations between computed parameters and experimen tal inhibition efficiency were discussed.

he effect of iodide ions on the corrosion inhibition of mild steel in 1 M sulfuric acid in the presence of poly(acrylamide-co-4-vinylpyridine) copolymer abbreviated by (AM-4VP-9) was studied by weight loss measurements and electrochemical techniques (impedance spectroscopy and polarisation curves) at 18 °C. The results obtained showed that the inhibition efficiency increased with increasing copolymer concentration. It was also found that the inhibition efficiency increased with the addition of potassium iodide (KI) to the copolymer. A synergistic effect was observed between the AM-4VP-9 copolymer and KI. On the other hand, it was found that the inhibiting effect of the system (AM-4VP-9 + KI) increased with increasing immersion time. Polarisation curves indicate that (AM-4VP-9) copolymer act as mixed inhibitors. EIS measurements show an increase of the transfer resistance with the inhibitor concentration.

The antifungal activity of different extracts of Astericus Imbricatus against botrytis cinerea isolated from tomato show that the percentage of the inhibition was almost100% for the four extracts of organic solvents at 500 ppm. At 250 ppm the percentage of inhibition was almost 70% for the ether extract and for the chloroform extract, 60 % and 50% for the ethyl acetate extract and for methanol extract, respectively. While the aqueous extract of Astericus Imbricatus exhibited moderate antifungal activity. The corrosion inhibition by an Astericus Imbricatus extract (AIE) on C38 steel in hydrochloric acid (HCl) solution has been investigated by electrochemical methods and weight loss. Potentiodynamic polarization studies clearly reveal that the presence of AIE does not change the mechanism of the hydrogen evolution reaction and they act essentially as cathodic and anodic inhibitor. Inhibition efficiency of AIE reached 96.33% at 0.6 g/l. The adsorption of AIE on C38 steel surface obeys the Langmuir isotherm.