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Effects of ultrasound on heterogeneous solid-liquid systems
Author
Teoh, Alex Chin Chye
Supervisor
Goh, Ngoh Khang
Abstract
In this study, the effects of ultra sound on some heterogeneous chemical systems have been investigated.
The results of ultrasonic irradiation of some metal and non-metal systems show that ultrasound can promote the related reactions at lower temperature and that the ultrasonic effect depends on the frequency and the power of the sonicators, the nature of the reactants, and the solvents used.
The findings from the ultrasonication of copper/lead with dilute hydrochloric acid indicate that the mechanical effects of sonication will depend mainly on the structural morphology and the size of the solid reactant(s).
The dehydration of copper(II) sulphate pentahydrate by ultrasound is probably attributed to thermal effects caused by microjet impacts and short waves. It is believed that the nature of the sonicating solvent used also plays a critical role in the process.
The increased reactivity of magnesium in cold water by ultrasound and the enhanced kinetics of aluminium-copper(II) chloride (aqueous) system under the sonication are probably associated with the depassivation of the oxide coating by ultrasound.
The experience from the ultrasonic extraction of chlorophyll reveals that ultrasound can be a viable alternative extraction technique which offers advantages over other conventional methods.
The optimal performance of deinking process under sonication depends on a number of factors, e.g. the type of solvent, operating parameters of the ultrasonic source, nature of the inks, and type of paper used, etc.
It has also been discussed that the outcome from some of the sonochemistry experiments conducted in this study can also serve as discrepant events which will capture the curiosity of learners and thus promote their learning interest. The justification as well as the procedure of bringing sonochemistry into high school chemistry curriculum have also been illustrated.
Thus, this study has resulted in some interesting and useful results. It has also led to the publication of three papers in the international refereed journals, and the presentation of two papers at the international conferences.
The results of ultrasonic irradiation of some metal and non-metal systems show that ultrasound can promote the related reactions at lower temperature and that the ultrasonic effect depends on the frequency and the power of the sonicators, the nature of the reactants, and the solvents used.
The findings from the ultrasonication of copper/lead with dilute hydrochloric acid indicate that the mechanical effects of sonication will depend mainly on the structural morphology and the size of the solid reactant(s).
The dehydration of copper(II) sulphate pentahydrate by ultrasound is probably attributed to thermal effects caused by microjet impacts and short waves. It is believed that the nature of the sonicating solvent used also plays a critical role in the process.
The increased reactivity of magnesium in cold water by ultrasound and the enhanced kinetics of aluminium-copper(II) chloride (aqueous) system under the sonication are probably associated with the depassivation of the oxide coating by ultrasound.
The experience from the ultrasonic extraction of chlorophyll reveals that ultrasound can be a viable alternative extraction technique which offers advantages over other conventional methods.
The optimal performance of deinking process under sonication depends on a number of factors, e.g. the type of solvent, operating parameters of the ultrasonic source, nature of the inks, and type of paper used, etc.
It has also been discussed that the outcome from some of the sonochemistry experiments conducted in this study can also serve as discrepant events which will capture the curiosity of learners and thus promote their learning interest. The justification as well as the procedure of bringing sonochemistry into high school chemistry curriculum have also been illustrated.
Thus, this study has resulted in some interesting and useful results. It has also led to the publication of three papers in the international refereed journals, and the presentation of two papers at the international conferences.
Date Issued
1997
Call Number
QD63.U4 Teo
Date Submitted
1997