Green Chemistry

Ultrasound Technology in Green Chemistry . . . . . . . .
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Ultrasound: Background Overview. . . . . . . . . . . . . .
3 Water Treatment . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 General Aspects. . . . . . . . . . . . . . . . . . . . . . .
3.2 Improving Disinfection. . . . . . . . . . . . . . . . . .
3.3 Intensifying Electrocoagulation . . . . . . . . . . . .
3.4 Enhancing Membrane Filtration. . . . . . . . . . . .
4 Sludge Stabilization . . . . . . . . . . . . . . . . . . . . . . . .
5 Sediment and Soil Remediation. . . . . . . . . . . . . . . .
5.1 Heavy Metals Removal . . . . . . . . . . . . . . . . .
5.2 Organic Decontamination . . . . . . . . . . . . . . . .
5.3 Ultrasonication as Assistant Process in Organic
Contaminated Soil Remediation. . . . . . . . . . . .
6 Air Pollution Control . . . . . . . . . . . . . . . . . . . . . . .
7 Environmental Analysis . . . . . . . . . . . . . . . . . . . . .
7.1 Assisting Microwave Digestion . . . . . . . . . . . .
7.2 Assisting Solvent Extraction . . . . . . . . . . . . . .
8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8 Conclusion Sonochemistry has been rapidly developing in recent years. Its potential in envi- ronmental applications is drawing more and more attention. Ultrasonic bath is widely used in analytical laboratories as an efficient method for solubilization, extraction assistance, and cleaning. Moreover, the utilization of ultrasound in environmental protection covers a broad range of applications: water treatment, soil remediation, and air cleaning. Among these environmental remediations, organic water decontamination is perhaps the most extensively researched, due to the fact that chemically ultrasonic effects work best in an aqueous medium because of the free radical formation during water sonolysis. On the other hand, the physical effects of ultrasound are recognized in membrane filtration, sediment heavy metal removal, dewatering, and air cleaning. However, it is generally accepted that ultrasonication alone cannot be a very cost-efficient technique. Ultrasound should rather be combined with other specific methods or work as an assistant for enhanced performance. Moreover, other physical impacts like heating, noise during ultrasonic process, and economic factors should also be considered, especially in practical scale-up systems. In general, as a part of a young and interesting science, the applications of ultrasound in the environmental and other green technology have a promising future.