NOPR Community:

Oxidative decolorization of methyl red dye with chloramine-T ─ Kinetic and mechanistic chemistry

Fri, 01 Nov 2013 00:00:00 GMT

Title: Oxidative decolorization of methyl red dye with chloramine-T ─ Kinetic and mechanistic chemistry Authors: Manjunatha, A S; Sukhdev, Anu; Puttaswamy Abstract: A simple and expeditious oxidative decolorization technique has been developed for the removal of Methyl Red dye (MR; C.I. Acid Red 2) present in the wastewater. The kinetic and mechanistic aspects of the present redox system have also been investigated. Kinetics and oxidative decolorization of MR dye with sodium N-chloro-p-toluenesulfonamide or chloramine-T (CAT) in HClO₄ medium at 303 K has been investigated spectrophotometrically at λ_max 524 nm. The reaction shows a first-order dependence of rate each on [CAT]_o and [MR]_o. The reaction is catalyzed by [HClO₄] and the order with respect to [H⁺] is found to be fractional (0.75). Activation parameters have been evaluated. The oxidation products of MR dye are identified as N-(4-dimethylamino-phenyl)-hydroxylamine and 4-nitroso-benzoic acid by GC-MS analysis. The observed results have been explained by a plausible mechanism and the related rate law is deduced. Further, the present redox system can be adopted for treating MR dye present in industrial effluents with suitable modifications to reduce the toxicity caused by MR dye. Page(s): 416-422

Studies on photoelectroactive (CdHg)Se films in different redox systems

Fri, 01 Nov 2013 00:00:00 GMT

Title: Studies on photoelectroactive (CdHg)Se films in different redox systems Authors: Tanveer, Md Rashid; Ansari, Shoeb A Abstract: Electrosynthesis of (CdHg)Se films has been carried out on titanium substrate by electrochemical codeposition method. Photoelectrochemical characteristics of these films studied in different redox solutions reveal that I₃^-/I₂ redox system is the most suitable solution for their characterization. Impedance measurements are used for the estimation of corrosion behaviour of the deposited films. The rate of corrosion is found to be comparatively lower when the electrodeposited films are tested in I₃^-/I₂ redox solution. Photoaction spectral studies are used to study light intensity dependence on photoactivity and also in the determination of band gap. The band gap values of the electrodeposited films are found to be independent to the nature of redox solution. Page(s): 411-415

Photocatalytic degradation of congo red dye on combustion synthesised Fe₂O₃

Fri, 01 Nov 2013 00:00:00 GMT

Title: Photocatalytic degradation of congo red dye on combustion synthesised Fe₂O₃ Authors: Dafare, Shyam; Deshpande, P S; Bhavsar, R S Abstract: This paper reports the semiconductor assisted photochemical degradation of reactive azo dye such as Congo Red on combustion synthesized ferric oxide as a photocatalyst. Oxalyldihydrazide is used as fuel in different molar proportions. Ferric oxide is characterized by powder XRD, Brunquer-Emmett-Teller (BET) surface area, scanning electron microscopy, reflectance spectroscopy and powder density. BET surface area is found to be 32 m²gm^-1and has a particle size equals to 66 nm. Energy gap is found to be 2.91 eV as observed by reflectance spectroscopy. Ninety seven per cent COD removal is observed at pH 6 within 90 min using UV light (254 nm wavelength) as a source of radiation. Page(s): 406-410

Electrochemical characteristics of micro and nano metre sized mixtures of cerium oxide incorporated aluminium

Fri, 01 Nov 2013 00:00:00 GMT

Title: Electrochemical characteristics of micro and nano metre sized mixtures of cerium oxide incorporated aluminium Authors: Muhamed, Ashraf P; Thomas, Saly N Abstract: The present study is aimed at investigating the electrochemical characteristics of aluminium due to the incorporation of nano metre and micro metre sized cerium oxide mixture. Treated aluminium exhibits higher corrosion resistance as evidenced by lower corrosion current density and corrosion rate and improved morphologies. Impedance spectra of aluminium subjected to long term exposure to 3.5% NaCl (w/v) show that the corrosion resistance of surface and internal matrix increases significantly and the corrosion is occurred in the β spaces of the aluminium. Smaller grain size and increased electronic conductivity improve the corrosion resistance of aluminium. Page(s): 400-405

NOPR Community:

Oxidative decolorization of methyl red dye with chloramine-T ─ Kinetic and mechanistic chemistry

Studies on photoelectroactive (CdHg)Se films in different redox systems

Photocatalytic degradation of congo red dye on combustion synthesised Fe2O3

Electrochemical characteristics of micro and nano metre sized mixtures of cerium oxide incorporated aluminium

Photocatalytic degradation of congo red dye on combustion synthesised Fe₂O₃