The enhancement of the dissolution rate of the sparingly soluble benzoic acid in aqueous solution by solid rotation, ultrasound and chemical reaction was investigated. The analysis indicated the strong influence of the ultrasound energy dissipation rate on the enhancement. The overall enhancements due to the three means were compared. The enhancement due to ultrasound was found to be much greater than mechanical rotation and comparable to that of chemical reaction. © 2004 Published by Elsevier B.V.

Aravamudan Kannan

Department Of Chemical Engineering

Sadhi Khan Pathan

Chemical reactions

Energy dissipation

Solids

Ultrasonics

benzoic acid

ULTRASOUND ENERGY DISSIPATION

dissolution

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Chemical Engineering Journal

The efficacy of power ultrasound of 20 kHz in enhancing the volumetric mass transfer coefficient was investigated in this study. Breakage and dissolution of sparingly soluble benzoic acid dispersed in either water or 24% aqueous glycerol was monitored as a function of time and ultrasound power input. Particle size measurements were carried out at intermediate times during the experiment to estimate the mean particle size and surface area. Linear combination of lognormal distributions was found to fit the experimental particle size distribution data. The De Brouckere mean diameters (d 43) obtained from the particle size distributions decreased with increase in the ultrasonic power level. Empirical correlations were developed for the evolution of surface area as a function of ultrasonic energy input per unit mass. The effect of ultrasound on the intrinsic mass transfer coefficient (kc) could be decoupled from the volumetric mass transfer coefficient (kca) as the surface area was also estimated. Different approaches involving either constant or variable intrinsic mass transfer coefficients were employed when carrying out the delineation. Mass transfer rates were enhanced due to both higher ultrasound induced intrinsic convective mass transfer coefficient and additional surface area created from particle breakage. To delineate the effects of particle breakage from solid dissolution, experiments were also carried out under non-mass transfer conditions by pre-saturating the solvents with benzoic acid. Both the solid-liquid systems examined in the present study attained saturation concentration when the ultrasonic energy input per unit mass was approximately 60 kJ/kg, irrespective of the ultrasonic power level setting. © 2011 Elsevier B.V. All rights reserved.

Fulltext

Ultrasonics Sonochemistry

Quantification of surface area and intrinsic mass transfer coefficient for ultrasound-assisted dissolution process of a sparingly soluble solid dispersed in aqueous solutions

The influence of power ultrasound (20 kHz) on the rate of attainment of saturation of sparingly soluble benzoic acid in distilled water and in 24% (w/w) aqueous glycerol was experimentally investigated at 30 °C. The importance of proper temperature control of process vessel contents when it was irradiated with high ultrasonic power level settings was demonstrated. A method was proposed to calculate the volumetric mass transfer coefficient under non-isothermal conditions. © 2009 Elsevier B.V. All rights reserved.

Effect of ultrasound on the solubility limit of a sparingly soluble solid

This paper investigates the effect of high-intensity ultrasound on the breakage characteristics of particles suspended in water. A continuous sonicated flow experimental apparatus is used involving a 24 kHz horn type transducer and continuous in-line particle chord length measurement. The effects of sonication power (150-350 W) and temperature (10-50 °C) on the breakage characteristics are investigated. Higher breakage is favored at higher sonication power. An optimum temperature in the range tested is observed to exist between 25 °C and 37 °C. The acoustic cavitation field is influenced by temperature through a complex interplay of vapor pressure, surface tension and viscosity leading to the optimum observed in particle breakage. The efficiency of ultrasound energy conversion to particle breakage is calculated using calorimetry and found along with the net breakage efficiency to initially increase with temperature followed by a decrease after the optimum. It is found to be independent of input ultrasonic power. The effects of contact time is also investigated. © 2007 Elsevier B.V. All rights reserved.

Experimental investigations on ultrasound mediated particle breakage

Industrial & Engineering Chemistry Research

Sonochemistry:  Science and Engineering

Engineering design and analysis of advanced physical fine coal cleaning technologies

Journal	Chemical Engineering Journal
ISSN	13858947
Open Access	No