title: Designing and characterizing a multi-stepped ultrasonic horn for enhanced sonochemical performance.
abstract: The commonly used ultrasonic horn generates localized cavitation below its converging tip resulting in a dense bubble cloud near the tip and limiting diffusion of reactive components into the bubble cloud or reactive radicals out of the bubble cloud. To improve contact between reactive components, a novel ultrasonic horn design was developed based on the principles of the dynamic wave equation. The horn, driven at 20 kHz, has a multi-stepped design with a cone-shaped tip increasing the energy-emitting surface areas and creating multiple reactive zones. Through different physical and chemical experiments, performance of the horn was compared to a typical horn driven at 20 kHz. Hydrophone measurements showed high acoustic pressure areas around the horn neck and tip. Sonochemiluminescence experiments verified multiple cavitation zones consistent with hydrophone readings. Calorimetry and dosimetry results demonstrated a higher energy efficiency (31.3%) and a larger hydroxyl radical formation rate constant (0.36 μM min(-1)) compared to typical horns. In addition, the new horn degraded naphthalene faster than the typical horn tested. The characterization results demonstrate that the multi-stepped horn configuration has the potential to improve the performance of ultrasound as an advanced oxidation technology by increasing the cavitation zone in the solution.
authors.affiliation: Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210, USA.
authors.forename: Zongsu
authors.initials: Z
authors.lastname: Wei
authors.affiliation: ETREMA Products, Inc., 2500 North Loop Drive, Ames, IA 50010, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Kosterman
authors.affiliation: Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210, USA.
authors.forename: Ruiyang
authors.initials: R
authors.lastname: Xiao
authors.affiliation: Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210, USA.
authors.forename: Gim-Yang
authors.initials: GY
authors.lastname: Pee
authors.affiliation: College of Environmental Science and Engineering, Zhejiang Gongshang University, 149 Jiaogong Road, Hangzhou 310035, China.
authors.forename: Meiqiang
authors.initials: M
authors.lastname: Cai
authors.affiliation: Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210, USA. Electronic address: weavers.1@osu.edu.
authors.forename: Linda K
authors.initials: LK
authors.lastname: Weavers
keywords: Calorimetry; Dosimetry; Hydrophone; Multi-stepped; Sonochemiluminescence; Sonolysis