Ultrasound in Process Engineering: New Look at Old Problems
When studying the action of 100-500 kHz ultrasound on aqueous solutions, Richards and Loomis (1927) discovered that the ultrasonic waves accelerate the hydrolysis of dimethylsulfate and the reduction of potassium iodate by sulfurous acid (iodine “clock” reaction). Two years later, Schmitt et al. (1929) reported the oxidation of iodide ions in aqueous solutions under the effect of 750 kHz ultrasound. These seminal works have introduced a new fi eld of chemistry, referred to as “sonochemistry” by Neppiras in 1980. Large amounts of research papers and detailed critical reviews have been published since that time describing different ultrasonic processes, such as cleaning and degassing (Mason and Lorimer 2002), extraction of biologically active compounds (Chemat 2011), food processing (Ashokkumar et al. 2008; Feng et al. 2011), advanced oxidation processes (Adewuyi 2001; Mahamuni and Adewuyi 2010), synthesis of nanostructured materials (Bang and Suslick 2010) and redox reactions of actinide ions (Nikitenko et al. 2010).