Presence Of Ultrasonic Irradiation Research Articles

Degradation of azo dye acid red B on manganese dioxide in the absence and presence of ultrasonic irradiation

Degradation of azo dye acid red B (ARB) on MnO 2 in the absence and presence of ultrasonic irradiation (sonication) has been investigated. The effect of initial pH, anions (Cl −, NO 3 −, SO 4 2−), and saturated gas (argon/oxygen) has been studied. The experimental results show that decolorization of the dye on MnO 2 is highly pH dependent, with increasing decolorization efficiencies at decreasing pH values. The SO 4 2− and NO 3 − ions are observed to suppress the adsorption of ARB on MnO 2 dramatically, suggesting competitive nature with the dye. Sonication accelerates decolorization and mineralization of the dye. And oxygen used as saturated gas is more favorable for mineralization of the dye than argon. The average particle diameter of MnO 2 decreases from 47.5 to 3.19 μm after sonication.

Studies on solution and solution-cast film of polyaniline colloids prepared in the absence and presence of ultrasonic irradiation

Spectroscopic and voltammetric features for the solution and solution-cast film of polyaniline (PANI) colloids prepared in the absence and presence of ultrasonic irradiation were examined. Significant differences in the color and absorption spectra between the solution of colloids prepared in the absence and presence of irradiation were observed. Effects of ambient atmosphere on the solution of colloids were also studied. A gradual decay in the absorption at ≈365 nm was occurred upon ageing the solution in air for the colloid prepared under ultrasonic irradiation. PANI film, cast from its colloidal solution, exhibited excellent electroactivity. The films thus cast were applied to electrode modification to control electrochemical reaction. Clear voltammetric response was observed on the electrode modified with the colloid prepared in the presence of ultrasonic irradiation.

Synthesis of Salicylic Acid Derivatives in Presence of Ultrasonic Irradiation Using Water as Solvent

An improved synthesis of salicylic acid using ultrasonic irradiation and water as solvent can be achieved with copper and pyridine as catalysts. A number of salicylic acids were prepared in good yield and in a short reaction time.

Observations on the heat capacity of activation (ΔCp‡) for the ultrasonically enhanced solvolyses of 2-chloro-2-methylpropane in aqueous ethanol mixtures

In the presence of ultrasonic irradiation the heat capacities of activation for the solvolysis of 2-chloro-2-methylpropane become large and positive in 30 and 50% w/w (xe= 0.1436 and 0.2813) ethanol–water mixtures.

The Effects of Ultrasonic Irradiation on Electroless Nickel Plating

SummaryThe effects of ultrasonic irradiation on electroless nickel plating were studied for both basic and practical purposes. The results reported here indicate that the application of ultrasound during the plating process can be beneficial. The rate of deposition is ncreased by ultrasound. The hardness of the resultant deposits was 635 VHN50 compared to 535 VHN50 for normal deposits. Significant changes in the microstructure of the Ni-P deposits were also observed. Deposits formed with ultrasound had a lower phosphorus content. The concentration of catalytic inhibitors, such as thiourea, was found to be critical in the presence of ultrasonic irradiation. The formulation of the experimental plating baths, exemplified by the metal-chelate stability constant, becomes an important factor when ultrasound is applied to an electroless nickel plating system.

Tetralin extraction of Jordan oil shale with ultrasonic irradiation

The kinetics of dissolution of decarbonated Jordan oil shale in tetralin, in the presence of ultrasonic irradiation at relatively low temperatures, has been evaluated. The solvolysis was found to fit a first-order integrated equation between 28 and 95 °C, and a second-order equation for the temperatures 121 and 132 °C. Negligible reverse reactions were detected when shale residue was exposed to the solution for long periods of time. A slurry of 1:1 ratio by weight of shale to solvent was found to be best for maximum yield of extract (oil). The rate processes were concluded to be determined by diffusion-controlled kinetics, with an apparent energy of activation of 7.15 kcal/mol ∗ ∗ 1 kcal/mol = 4.187kJ/mol. , and apparent enthalpy and entropy according to the Eyring equation of 5.2 kcal/mol and −58 e.u. † † 1 e.u. = 4.187 kJ/mol K. respectively.