Benzyl dimethyl dodecyl ammonium chloride-zinc ion system, as quaternary ammonium salt (QA-Zn +2), was investigated as corrosion inhibitor for carbon steel in a 2.0 M sodium chloride solution, by different techniques such as weight loss, open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopic techniques. The inhibition efficiency of the used system (QA-Zn +2) increases with increasing mixed inhibitor concentrations and with rising temperatures. A synergistic effect exists between QA and Zn +2. Potentiodynamic polarization curves indicate that the used system mainly acts as an anodic mixed inhibitor. The polarization resistance values were (Rp) increased, and the interface capacitance (Cdl) was decreased in the mixed inhibitor system (QA-Zn +2) presence, more than in the case of individual inhibitors. The corrosion inhibition is due to the adsorption of (QA-Zn +2) onto the metal surface, and the formation of a barrier film that separates the metal from the corrosive medium. The maximum inhibition efficiency of 98% was obtained at 200 QA and 50 ppm Zn +2 of the mixed inhibitor system, due to a synergistic effect.

Expired ranitidine was tested as a corrosion inhibitor for mild steel in 1 M HCl using different techniques: weight loss, potentiodynamic polarization, open circuit potential and electrochemical impedance spectroscopy. The polarization resistance (R p ) value increased with increase in the concentration of the inhibitor. Results obtained revealed that ranitidine performed excellently as a corrosion inhibitor for mild steel in this medium at 303 K. The protection efficiency increased with increasing inhibitor concentration. The maximum protection efficiency of 90% has been obtained at 400 ppm. On the other hand, the efficiency decreases with increasing temperature. The adsorption of the inhibitor on the mild steel surface followed Langmuir adsorption isotherm model. The activation and thermodynamic parameters of dissolution and adsorption were calculated and discussed. The negative value of ∆G ads (-40 kJ mol

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Three Schiff' bases (SB) were synthesized, characterized and evaluated as corrosion inhibitor for aluminum in 1.0 M HCl using chemical (weight loss) and electrochemical (open circuit potential, potentiodynamic polarization, and electrochemical impedance) techniques. The influence of temperature and concentration was investigated. It has been shown that the efficiency of corrosion inhibition increases with the inhibitor concentration and decreases with increasing temperature. The addition of the inhibitor molecules to the corrosive medium shifts the corrosion potential (Ecorr) to the nobler direction. It has been found that the adsorption of the used compounds obeys the Langmuir adsorption isotherm.

Aluminum (Al) is a ubiquitous element with known toxicity for both humans and animals. Herein, we aimed to investigate the potential role of melatonin (MEL) in hepatotoxicity and nephrotoxicity following aluminum chloride (AlCl3) treatment in rats. Adult male rats were treated with AlCl3 (34 mg/kg bwt) for eight weeks. Exposure to AlCl3 enhanced the serum activities of the liver transaminases (alanine aminotransferase and aspartate aminotransferase) and increased the level of bilirubin, in addition to the serum kidney function markers urea and creatinine. AlCl3 intoxication boosted oxidative stress, as evidenced by increases in the levels of lipid peroxidation (LPO) and nitric oxide (NO) along with simultaneous decreases in the levels of glutathione (GSH), various antioxidant enzymes, and Nrf2 mRNA expression. MEL (5 mg/kg bwt) treatment repressed LPO and NO levels, whereas it augmented GSH content. The activities of the antioxidant enzymes GPx, SOD, CAT, and GR were also restored concomitantly when MEL was administered before AlCl3. MEL also suppressed the apoptotic effect of AlCl3 by enhancing Bcl-2 protein expression in the liver and kidney and decreasing the expression levels of proinflammatory cytokines. Histopathological findings in the liver and kidney tissues confirmed the beneficial effect of MEL against AlCl3 toxicity. These findings indicate that MEL prevents AlCl3 toxicity by enhancing the antioxidant defense system.