Ultrasonics and sonochemistry: Editors' perspective

Abstract

Ultrasonic waves can induce physical and chemical changes in liquid media via acoustic cavitation. Various applications have benefitted from utilizing these effects, including but not limited to the synthesis of functional materials, emulsification, cleaning, and processing. Several books and review articles in the public domain cover both fundamental and applied aspects of ultrasonics and sonochemistry. The Editors of the Ultrasonics Sonochemistry journal possess diverse expertise in this field, from theoretical and experimental aspects of acoustic cavitation to materials synthesis, environmental remediation, and sonoprocessing. This article provides Editors' perspectives on various aspects of ultrasonics and sonochemistry that may benefit students and early career researchers.

Keywords: Environmental remediation; Nanomaterials; Sonochemistry; Sonoprocessing; Ultrasonics.

Fig. 1

An ultrasonic scanning equipment for diagnosing thyroid cancer. Image courtesy of WebMed. ©2021, WebMD, LLC. All rights reserved.

Fig. 2

Schematic representation of acoustic cavitation.

Fig. 3

Evolution of (R_max-R₀)/R₀ (with R_max the maximum bubble size and R₀ the rest radius) with frequency and R₀ for a driving acoustic pressure of 100 kPa (a) and 200 kPa (b). Resonance sizes are in the white regions; arrows indicate the Blake threshold.

Fig. 4

Microstreaming, microjetand shockwavesgenerated during acoustic cavitation.

Fig. 5

The amount of H₂O₂ (an indirect measure of the amount of OH radicals generated) produced as a function of US frequency. H₂O₂ yields were measured using the iodide oxidation method, and the acoustic power was kept constant at 0.9 W/cm².

Fig. 6

Schematic of the temperature profile for the US-generated hot spot theory for a cavitation bubble (a) and corresponding profiles of temperature (T), ·OH, and pollutants (b; the vertical axis is arbitrary).

Fig. 7

Field implementation of river sediment combined US and O₃ treatment.

Fig. 8

Papers published from 2011 to May 2023. Searched keywords were “ultrasound” and “processing” or “sonoprocessing”. Data extracted from Web of Science, Clarivate Analytics.

Fig. 9

Images of the obtained O/W emulsions of different oils: medium chain triglycerides (MCT) oil, palm oil, soy oil and rapeseed oil. Images were acquired by optical microscopy. H 6: high shear homogenisation (conventional method) for 6 min, S 6: 6 min of sonication, S 18: 18 min of sonication.

Fig. 10

Pictures of the reaction flasks after US treatment for (A) 1 min at 45 kHz; (B) 15 min at 25 kHz; (C) 15 min at 35 kHz; and (D) 15 min at 45 kHz.

Fig. 11

Studies on sonoprocessing published from 2011 to May 2023. Searched keywords were “ultrasound” and “processing” or “sonoprocessing”. Data extracted from Web of Science, Clarivate Analytics.

Fig. 12

HR-TEM micrographs of GO sheets obtained from sonication in NMP (a and b) and DI water (c and d).

Fig. 13

Benefits of sonoelectrochemistry.

Fig. 14

The use of power US in electrochemistry.

Fig. 15

Various sono(electro)chemical reactors/cells.

Fig. 16

A schematic diagram of a sonoelectrochemical reactor set-up for producing nanomaterials , .

Fig. 17

Google Scholar research on publications containing “sonochemistry” “sonochemical” or “ultrasound-assisted” words.

Fig. 18

Google Scholar research on publications containing “sonochemistry”, “ultrasound” and “continuous” words.