The corrosion inhibition of mild steel in a 1.0 M hydrochloric acid solution by 2-(4,5-diphenyl-4,5-dihydro-1h-imidazol-2-yl)-5-methoxyphenol (P1) has been studied in relation to the concentration of the inhibitor, as well as to the temperature, using chemical (weight loss) and electrochemical techniques. All the employed methods were in reasonable agreement. The protection efficiency increased with an increased inhibitor's concentration. The obtained thermodynamic adsorption parameters (∆G * ads, ∆H * ads, ∆S * ads) indicated that this polymer retarded both cathodic and anodic processes through physical adsorption, and blocked the active corrosion sites. It was also found that this compound obeyed the Langmuir's adsorption isotherm.

A variable order kinetic (VOK) model derived from the langmuir-freundlish equation was applied to determine the kinetics of fluoride removal reaction by electrocoagulation (EC). Synthetic solutions were employed to elucidate the effects of the initial fluoride concentration, the applied current and the initial acidity on the simulation results of the model. The proposed model successfully describes the fluoride removal in Airlift reactor in comparison with the experimental results. In this study two EC cells with the same capacity (V = 20 L) were used to carry out fluoride removal with aluminum electrodes, the first is a stirred tank reactor (STR) the second is an airlift reactor (ALR). The comparison of energy consumption demonstrates that the (ALR) is advantageous for carrying out the defluoridation removal process

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Thymus Sahraouian essential oil (TSEO), as a new corrosion eco-friendly inhibitor, has been used to protect mild steel in 1 M HCl. Weight loss, three potentiodynamic polarization methods (Tafel, Stern and Stern-Geary), and electrochemical impedance spectroscopy measurements were undertaken to evaluate corrosion inhibition by TSEO. TSEO acted as an efficient corrosion inhibitor for mild steel in 1 M HCl, and its inhibition efficiency increased with a concentration of 77.82 % at 2 g L -1 . The polarization curves revealed that TSEO acted as a mixed type inhibitor, with predominant anodic action. The EIS studies were fitted to a suitable equivalent circuit model, at 293 K, only reflecting a one-time constant characteristic of a charge transfer process. Besides, the higher is the temperature the lowest is the inhibiting efficiency. The kinetic parameters were in favour of an electrostatic character of TSEO components adsorption onto the mild steel surface, and adsorption followed the Langmuir isotherm model. Micrographic scanning electron microscopy and energy dispersive X-ray spectroscopy analyses confirmed the formation of a protective adsorbed film upon the mild steel surface.

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