Professor Linda Weavers is studying the effects of ultrasonic waves on the degradation of water pollutants. Ultrasonic waves, when applied to water, result in cavitation bubbles. These microscopic bubbles grow and collapse with the ultrasound. Upon collapse, the bubbles generate extremely high temperatures (hotter than the sun!) and pressures (approximately 1000 atmospheres). As a result of these extreme conditions, the chemical bonds of water are broken generating reactive and highly oxidizing chemical species. In addition, contaminants in the water entering the cavitation bubbles undergo high temperature gas phase reactions.
The Weavers research group is exploiting these processes to selectively degrade pollutants that preferentially accumulate on air/water surfaces (i.e., on the bubbles). In addition, they are exploring the use of pulsed ultrasound to increase the efficiency of the ultrasound in environmental applications. Pollutants that Dr. Weavers and her students have targeted include perfluorooctanyl sulfonate (PFOS), free and complexed EDTA, linear alkyl benzene sulfonate surfactants, and pharmaceuticals and personal care products (PPCPs).
Another of Dr. Weavers’ current ultrasound-based research projects is focused on desorption of toxic inorganic and organic contaminants from sediments. Specifically, she and her team are interested in understanding exactly how ultrasound works to treat contaminated sediments. This will enable them to determine if ultrasound could be used to treat all types of contaminated sediment and to understand how to make the process work better and cheaper.