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In this study, the efficiency of EC/UV/TiO2 and EC/UV/ZnO coupled systems, on the decolorization of C.I. Acid Yellow 23 (AY23) as a model contaminant was compared. It was found that for the efficient decolorization of 40 mg L-1 of AY23 using steel304/Al (anode/cathode) as electrodes, with the distance of 15 mm, I = 120 A m-2, electrolyte concentration was 800 mg L-1 for both systems, but pH and initial concentrations of catalysts were 5.53, 800 mg L-1 for TiO2 and 6.29, 650 mg L-1 for ZnO systems, respectively. Th...

The decolorization of Acid Yellow 42 (AY42) by Fenton and electro-Fenton processes was compared. The effect of operational parameters was studied and the desired conditions obtained in the initial dye concentration of 120 mg L-1 for H2O2/ Fe2+ ([H2O2]=800 mg L-1, [Fe2+]=0.2 mmol, pH=3) and electrolysis/Fe2+/H2O2 ([H2O2]=1100 mg L-1 , [Fe2+]= 0.5 mmol, pH=3.5 and distance of electrodes 10 mm) systems. The Fenton process proved to be more efficient and occurs at a higher oxidation rate than electro-Fenton process an...

The aim of this study is development of design equation for batch-recirculated reactor at photooxidative removal of C.I. Acid Red 17 (AR17) as a model contaminant from textile industry with UV/H2O2 process. Reactor which used is a combination of an annular photoreactor with UV-C lamp emitting at 254 nm from center of photoreactor and a continuous stirred tank reactor (CSTR). Design equation developed by combining of the mass balance and rate equation. This equation predicts that pseudo-first-order reaction rate co...

The present study deals with the decolorization of C.I. Acid Red 88 (AR88) as a model contaminant from textile industry using sawdust as an adsorbent. The effects of initial AR88 concentration, adsorbent dosage, pH, contact time and stirring rate were studied in a batch mode. The variation of pH from 3 to 10 showed no considerable change in decolorization rate. The desired conditions for decolorization of 84.46\% were obtained to be 20 min of contact time, stirring rate of 400 rpm with 30 g L-1 of adsorbent. Freun...

Magnesium doped TiO2 nanoparticles were synthesized by sol-gel method. The crystallite size of nanoparticles was obtained by X-Ray diffraction (XRD). The photocatalytic activity of magnesium doped TiO2 was tested by photocatalytic degradation of C.I. Acid Red 27 from mono azo textile dyes. Results show that magnesium doped TiO2 under visible light has high photocatalytical activity than undoped TiO2 nanoparticles.

ZnO-SnO2 coupled catalyst was prepared by coprecipitation method. Then Ag was loaded on the coupled catalyst by impregnation method. The photocatalytic performance of silver doped ZnO-SnO2 was tested by photocatalytic degradation of C.I. Acid Red 27 (AR27) as a model contaminant from mono azo textile dyes. The crystallite size of nanoparticles was obtained by X-Ray diffraction (XRD). Results demonstrate that silver doped ZnO-SnO2 have shown high photocatalytic efficiency than undoped ZnO-SnO2 at photocatalytic deg...

Bond-Order Conservation-Morse Potential (BOC-MP) method is used in order to carry out the calculation. One of the best catalysts for methanol synthesis in catalytic reduction of CO2 with H2O is Cu/ZnO/Al2O3 whose surface is supported by with some amount of Pd or Ga. Reduction of CO2 with H2O on Cu will result in methanol formation; while on Ni will lead to methane formation. In the mechanism of methanol synthesis from CO2+ H2O on Cu, the formate (HCOO) hydrogenation step is ratedetermining step and in the mechanis...

The goals of the present work are: (1) A theoretical analysis of possible reaction pathways to the synthesis of methanol and methane from CO2 and H2O and the selection of the best path from the view point of energy. (2) Investigation of the kinetic of assumed reactions. For determination of mechanism, BOC-MP method is used. By using of this theory, it is possible to calculate the thermodynamic and kinetic parameters and therefore predict the intermediates and the mechanism of heterogeneous catalytic reaction. With...

With developing industries particularly dying industries and complication in the structure of dye molecules and resulting wastewaters from these plants cause a serious threat to the environment (due to resistance to biological treatment). The aim of this study was to investigate the efficiency of coupled system (UV/ZnO+SnO2) in the removal of acid yellow 23 (AY23) a mono-azo dye from aqueous solutions. In these experiments ZnO and SnO2 were employed in a single and coupled form in slurry conditions and the optimum...

The photodegradation of Acid Yellow 23 a model compound from monoazo textile dyes was investigated using TiO2, SnO2 and TiO2+SnO2 suspension as photocatalysts at different gap sizes. The results showed that the coupled particles were not much different from single TiO2 system at the gap size of 4.5 cm in a batch reactor. But the coupled system was more effective when the gap size was reduced to 2.5 cm. A complete decolorization occurs at the gap size of 1.1 cm after 20 min of irradiation while 90\% decolorization ...