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Electrodeposition mechanism of aluminium from aluminium chloride-N-(n-butyl)pyridinium chloride room temperature molten salt

2013-04-15T16:33:33Z

Title: Electrodeposition mechanism of aluminium from aluminium chloride-N-(n-butyl)pyridinium chloride room temperature molten salt Authors: Ali, M R; Nishikata, A; Tsuru, T Abstract: Electrodeposition of aluminium has been carried out by controlled-current and controlled-potential methods from acidic aluminum(III) chloride-N-(n-butyl)pyridinium chloride (BPC) molten bath at room temperature. The electrodeposition of aluminium from acidic AlCl₃-BPC melt occurs via instantaneous nucleation mechanism in the very initial stage of the crystal growth. The deposition reaction mechanisms of aluminium in the acidic AlCl₃-BPC molten bath are revealed by electrochemical analysis. The experimental Tafel slope of 20 mV dec^-1 and the calculated transfer coefficient (α_c) of 3 suggest that the rate determining step is a chemical reaction involving the release of the complexing agents via three consecutive single electron transfer steps. The influence of various conditions on electrodeposition and the morphology of the electrodeposited layers have been investigated by X-ray diffractometry and scanning electron microscopy. On increasing the current density smaller particle size and better adhesiveness of the electrodeposited layers have been obtained. The cathodic current efficiency for the deposition of Aluminium is about 99.8%. Page(s): 317-324

Synthesis and characterization of epoxy resins containing zinc chloride

2013-04-24T16:32:38Z

Title: Synthesis and characterization of epoxy resins containing zinc chloride Authors: Pandey, Saurabh; Srivastava, A K Abstract: As evidenced from IR spectroscopy, ZnCl₂-forms a complex with oxygen atom of epichlorohydrin and thus cures the epoxy resins simultanteusly. Differential Scanning Calorimetry (DSC) studies show that the properties, like degree of cure, percent crystallinity, glass transition temperature of the epoxy resin improved significantly. The Scanning Electron Microscopy (SEM) studies confirms the presence of zinc metal in the epoxy resin. The activation energy is 95 KJ/mol and order of reaction is first. Page(s): 313-316

Hydrazine and substituted hydrazines as corrosion inhibitors for mild steel in simulated seawater

2013-04-15T16:33:24Z

Title: Hydrazine and substituted hydrazines as corrosion inhibitors for mild steel in simulated seawater Authors: Suresh, G S; Aravinda, C L; Ahamed, M F; Mayanna, S M Abstract: The corrosion of mild steel in simulated seawater containing various concentrations of hydrazine, phenylhydrazine and 2, 4-dinitrophenylhydrazine has been studied by polarization technique. These compounds inhibit corrosion effectively even in trace concentration. The degree of corrosion inhibition is a function of temperature, concentration and nature of the inhibitor. The corrosion current density, percentage inhibitor efficiency and thermodynamic parameters for the surface adsorption of inhibitors were calculated for the inhibition process. The IR spectra of the film formed on the corroding surface indicated the formation of complex between the inhibitor molecule and the mild steel. The inhibitors appeared to function through a general adsorption mode following the Frumkin adsorption isotherm. The thermodynamic parameters of adsorption showed a strong interaction of these inhibitor molecules with the mild steel surface. The results revealed that these compounds act as mixed inhibitors for mild steel in simulated seawater. Page(s): 301-304

Photo-oxidative degradation of Direct Yellow 12 using hydrogen peroxide

2013-04-17T16:33:04Z

Title: Photo-oxidative degradation of Direct Yellow 12 using hydrogen peroxide Authors: Rathi, Aparna; Pandit, M; Sharma, R K Abstract: The photo-oxidation process by combination of UV light and H₂O₂ generates hydroxyl radicals which are capable of oxidising many organic compounds which are refractory type and difficult to oxidize by conventional chemical treatment. In the present study, photo-oxidation of Direct Yellow 12 (DY 12) dye has been carried out in an annular type photoreactor using 8 Watt low pressure mercury lamp along with H₂O₂ as oxidant. Synthetic dye solutions of 50 mg/L concentration were used to carry out the experiments. Complete dye degradation and colour removal took place within 30 min with 85-95 % reduction in COD (Chemical Oxygen Demand) value. The process of degradation is dependent upon the pH of the solution. Page(s): 297-300