Sonochemistry, specifically dependent on acoustic cavitation, has transformed chemical engineering through its possibilities of provocation of localized temperature and pressure. This chapter will discuss sonochemical technology, specifically ultrasonic reactors, which include ultrasonic baths, horns, and multiple-frequency flow cell reactors. Bubble dynamics are modeled according to the Rayleigh-Plesset equation together with the role of frequency, temperature, pressure, liquid, reactor geometry, and the transducer’s position. It has been used in nanoparticle preparation, nanoemulsion process, filtration process, ultrasonic atomization, and improvement of reaction rates in polymerization process, catalysis process, and enzymatic process. The chapter also discusses mass transfer modeling, namely the diffusion-limited model for vapor transport, ultrasound generation methods, piezoelectric and magnetostrictive transducers. Comparisons of sonochemistry with other hybrid technologies in controlling air contamination and biological wastewater treatment are also provided to highlight the importance of sonochemistry in developing more sustainable and innovative chemical engineering methods.