The purpose of this work was to understand
the effect of the acoustic
cavitation on the alkaline hydrolysis of wool and compare it with
a conventional method of steam based alkaline hydrolysis. In acoustic
cavitation assisted alkaline hydrolysis, the effect of concentration
of solid (wool) and alkali on the properties of wool were also investigated.
In conventional alkaline hydrolysis, the experiments were carried
in a laboratory scale autoclave at temperature of 120 °C and
pressure of 2 bar for 15 min. While acoustic cavitation assisted hydrolysis
was carried out using the untreated and treated wool, hydrolyzed samples
were characterized using FTIR, TGA and DSC to find out the extent
of structural degradation occurring as a result of the treatment.
It was observed that both the processes resulted in to a cleavage
of disulfide bonds in wool, which cross-link the protein chains and
are responsible for the higher stability and lower solubility of wool.
However, the acoustic assisted alkaline hydrolysis is an environmentally
friendly and less energy intensive process as it was performed at
room temperature. The wool hydrolysates produced using acoustic assisted
alkaline hydrolysis could find a potential application in agricultural
fields such as fertilizer, soil improvement additive, etc.
This work reports on the process optimization of ultrasound-assisted, paraffin wax in water nanoemulsions, stabilized by modified sodium dodecyl sulfate (SDS). This work focuses on the optimization of major emulsification process variables including sonication time, applied power and surfactant concentration. The effects of these variables were investigated on the basis of mean droplet diameter and stability of the prepared emulsion. It was found that the stable emulsion with droplet diameters about 160.9 nm could be formed with the surfactant concentration of 10 mg/ml and treated at 40% of applied power (power density: 0.61 W/ml) for 15 min. Scanning electron microscopy (SEM) was used to study the morphology of the emulsion droplets. The droplets were solid at room temperature, showing bright spots under polarized light and a spherical shape under SEM. The electrophoretic properties of emulsion droplets showed a negative zeta potential due to the adsorption of head sulfate groups of the SDS surfactant. For the sake of comparison, paraffin wax emulsion was prepared via emulsion inversion point method and was checked its intrinsic stability. Visually, it was found that the emulsion get separated/creamed within 30 min. while the emulsion prepared via ultrasonically is stable for more than 3 months. From this study, it was found that the ultrasound-assisted emulsification process could be successfully used for the preparation of stable paraffin wax nanoemulsions.
This work deals with the extraction of date seed oil using an acoustic cavitation. The process parameters such as sonication (extraction) time, power dissipation, operating temperature and solvent to date seed ratio have been optimized on the basis of extracted oil yield. The obtained results have been compared with the frequently used extraction methods (such as maceration and Soxhlet extraction method).The highest extraction efficiency was found at solvent (hexane) to seed ratio of 5, applied rated power of 30 % of 750 W (actual dissipated power is 2.98 W), ultrasound treatment time of 45 min, at a temperature of 20 0 C. It was observed that, as ultrasonic power dissipation increases, the oil extraction yield of also increases and decline with an increase in temperature. This results attributed to only physical effects of cavitation occur onto the surface of the date seeds which enhance the permeability of solvent into the plant tissues due to the formation of crack, crevices and micro fractures onto seed surface. A comparison of field emission scanning electron microscopy (FE-SEM) images of fresh date seed and ultrasonically treated date seed indicated the development of crack, crevices and micro fractures onto seed surface of date seed which results the cell walls disruption. However, the cavitation assisted oil extraction has reduced environmental impact and less time and energy intensive process as it was performed at room temperature.
The process intensification (PI)
can significantly improve energy
and process efficiency by enhancing mixing, mass, and heat transfer
as well as driving forces. There are several benefits of such improvements,
which include energy and cost savings, enhanced safety, smaller reactor
size, less waste generation, and higher product quality. This review
article focuses on the PI, discussion about its dimensions and structure,
what it involves, and recent developments in PI which can be achieved
using the technique of cavitation. Recommendations for optimum operating
parameters needed for process intensification using cavitation phenomena
which has been reported in the literature have been presented along
with some of our own work in the area. Some experimental case studies
have been presented which highlight the degree of intensification
achieved when cavitation is used for different physicochemical transformations.
These physicochemical transformations include crystallization, emulsification,
extraction, wastewater treatment, depolymerization, and water disinfection.
In this article, an acoustic cavitation engineered novel approach for the synthesis of TiO2, cerium and Fe doped TiO2 nanophotocatalysts is reported. The prepared TiO2, cerium and Fe doped TiO2 nanophotocatalysts were characterized by XRD and TEM analysis to evaluate its structure and morphology. Photo catalytic performance of undoped TiO2 catalyst was investigated for the decolorization of crystal violet dye in aqueous solution at pH of 6.5 in the presence of hydro dynamic cavitation. Effect of catalyst doping with Fe and Ce was also studied for the decolorization of crystal violet dye. The results shows that, 0.8% of Fe-doped TiO2 exhibits maximum photocatalytic activity in the decolorization study of crystal violet dye due to the presence of Fe in the TiO2 and it may acts as a fenton reagent. Kinetic studies have also been reported for the hybrid AOP (HAOP) that followed the pseudo first-order reaction kinetics.
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