The destruction of toxic organic molecules using advanced oxidation processes (AOPs) is a potent tool for pollution control and environmental protection. Ultrasound is a convenient and effective method of generating hydroxyl radicals which is the key oxidant in AOPs. This review describes the use of ultrasound and associated chemical reactions, with and without additives, as a powerful means of remediating water contaminated with organic pollutants. After a brief introduction to ultrasound and sonochemistry, their application for the oxidation of polycyclic aromatic hydrocarbons, phenol and substituted phenols is considered. Next is the decomposition of chlorinated phenols, and other chlorinated organics, then removal of recalcitrant smaller organic molecules. A discussion follows of recent work that has investigated the effects of initial concentration of substrates; the use of different ultrasonic frequencies; the inclusion of oxidising species, inorganic particles, or salts and their contribution to enhanced degradation. Finally, brief comments are made on the status of ultrasound as an AOP treatment.
Keywords: Sonication, degradation, oxidation, pollutants, hydroxyl radicals, advanced oxidation process, Ultrasonic Degradation, ultrasound, organic pollutants, sonochemistry, chlo-rinated phenols, multi-hyphenated processes, sono-electrochemistry, sonophotochemistry, sono-luminescene, hydrodynamic cavitational techniques, dimerisation, Polycyclic Aromatic Hydrocarbons (PAHs), sono-degradation, radical scavenging, sonolysis, sonoproducts, Henry's Law constants, Fenton-like conditions, ultrasound irradiation, phenol mineralisation, advanced Fenton process, organic carbon (TOC), Degradation of Substituted Phenols, ar-gon-saturated water, oxidative-pyrolytic degradation, acoustic pressure, oestogenic activity, sono-Fenton process, fungus Paecilomyces lilacinus, humic acids, sonicator, HPLC analyses, bisphenol-A (BPA), classi-cal Fenton reaction, DEGRADATION OF CHLORINATED ORGANICS, degrade aromatic pollutants, pyrolysis, copper catalysed Fenton reactions, Polychlorinated phenols, Pentachlorophenol (PCP), 2-chloro-5-methylphenol (2C5MP), 2,4-dichlorophenoxyacetic acid, chlorobenzene (CB), Nitro-aromatics, zeolites, sonochemi-cal oxidation, sonochemical reactor, hexagonal flow cell, cup-horn reactor, methyl t-butyl ether (MTBE), 2-methylisoborneol (MIB), geosmin (GSM), Ibuprofen (IBP)