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The purpose of this study was to investigate the inhibitive action of some green leaves on Monel 400 alloy in acidic media.

Green leaves of Mespilus japonica, Ricinus communis L and Vitis vinifera were immersed in methanol solutions, separately, and filtrated after 48 h of immersion; the obtained filtrates were examined as corrosion inhibitors of Monel 400 alloy in hydrochloric acid solution (1.0M HCl). The performance of these inhibitors was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization. The effect of temperature on corrosion behavior of Monel 400 was also studied.

The results obtained showed that all tested inhibitors performed as good corrosion inhibitors. The inhibition process is attributed to the adsorption of the inhibitors on Monel surface. The adsorption behavior was found to follow Langmiur isotherm. The inhibition efficiencies of extracts increased with increasing the concentration of each inhibitor and deceased with increasing the temperature.

Practical implication These inhibitors could have application in industries where hydrochloric solutions were used to remove the surface impurities of Monel 400.

This paper helps to find new corrosion inhibitors that are safe and eco-friendly.

Corrosion and corrosion inhibition of alloyed zinc electrode were investigated in neutral chloride solution using electrochemical techniques. The purpose of this study is to study the corrosion inhibition of acetanilide and para hydroxy acetanilide as organics inhibitors for corrosion control of alloyed zinc electrode in NaCl 3 per cent solution.

A volt lab PGZ 301, assembled using alloyed zinc working electrode, a platinum counter electrode and a saturated calomel electrode as the reference electrode, was used in the experiment. This research was conducted using potentiodynamic polarization and electrochemical impedance spectroscopy techniques.

Acetanilide, para hydroxy acetanilide and their mixture provided inhibitions efficiencies of 88 per cent at 40 ppm, 87 per cent with 80 ppm and 99.86 per cent with (40 ppm AC + 80 ppm PHA), respectively. The study also discusses the corrosion inhibition mechanism of the protective layers. The adsorption of acetanilide and para hydroxy acetanilide on metal surface obeyed Langmuir’s adsorption isotherm. Polarization measurements showed that the acetanilide and the para hydroxy acetanilide, and their mixture acted as cathodic inhibitors in NaCl solution, and the inhibitor molecules followed physical adsorption on the surface of alloyed zinc.

The other new inhibitors which are very efficient inhibitors and to be applied in the field of prevention and control against corrosion.

The purpose of this paper is to focus on the removal of hexavalent chromium [Cr(VI)] from wastewater by using activated carbon-supported Fe catalysts derived from walnut shell prepared using a wetness impregnation process. The different conditions of preparation such as impregnation rate and calcination conditions (temperature and time) were optimized to determine their effects on the catalyst’s characteristics.

The catalyst samples were characterized using thermogravimetric analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption of Cr(VI) by using using activated carbon supported Fe catalysts derived from walnut shell as an adsorbent and catalyst was investigated under different adsorption conditions. The parameters studied were contact time, adsorbent dose, solution pH and initial concentrations.

Results showed that higher adsorption capacity and rapid kinetics were obtained when the activated walnut shell was impregnated with Fe at 5 per cent and calcined under N₂ flow at 400°C for 2 h. The adsorption isotherms data were analyzed with Langmuir and Freundlich models. The better fit is obtained with the Langmuir model with a maximum adsorption capacity of 29.67 mg/g for Cr(VI) on Fe5-AWS at pH 2.0.

A comparison of two kinetic models shows that the adsorption isotherms system is better described by the pseudo-first-order kinetic model.