Hydroxyl Radical Production via Acoustic Cavitation in Ultrasonic Humidifier Systems

Ultrasonic humidifiers use sound vibrations at frequencies higher than can be heard by humans (> 20,000 Hz) to generate aerosolized water also have potential for inducing sonochemical reactions for chemicals present in water. This research focuses on examining oxidants formed within ultrasonic humidifiers, as well as the oxidants effects of contaminants in water used in the systems. Hydroxyl radicals were found using DMPO as a spin trap. Caffeine and 17β-estradiol, as pharmaceutical contaminants of drinking water, were both emitted from the humidifier when present in the water reservoir and would enter breathing air. Emitted 17β-estradiol was found at 60% of the initial concentration filled in the ultrasonic humidifier after 480 minutes. Caffeine exhibited less degradation than 17β-estradiol. Degradation of both pharmaceuticals was attributed to ultrasonic processes, most likely oxidation with hydroxyl radicals produced. Bromide as a contaminant of the fill water was found to remain constant over time.

Name thesis:degree_name

MS

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Environmental Sciences and Engineering

Department dc:contributor.department

Environmental Science and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2018

Author dc:creator

• Altizer, Chase Duncan

Chair dc:contributor.committeechair

• Dietrich, Andrea M.

Committee members dc:contributor.committeemember

• Isaacman-VanWertz, Gabriel
• Tanko, James M.

• hydroxyl radical
• acoustic cavitation
• ultrasonic humidifier
• sonochemistry
• ultrasound

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:14973

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/95935