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Web End = Environ Chem Lett (2016) 14:259290 DOI 10.1007/s10311-016-0568-0
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Web End = REVIEW
Degradation of pharmaceuticals by ultrasound-based advanced oxidation process
Manoj P. Rayaroth1 Usha K. Aravind2 Charuvila T. Aravindakumar1,3
Received: 13 March 2016 / Accepted: 16 June 2016 / Published online: 28 June 2016 Springer International Publishing Switzerland 2016
Abstract Water pollution by pharmaceutically active compounds is an emerging issue. Toxicological studies reveal that pharmaceuticals are indeed toxic for living organisms. The lack of suitable treatment technology for the complete removal of pharmaceuticals is therefore a major challenge. Advanced oxidation processes are emerging removal techniques that have many advantages versus conventional technologies. Many studies indicate that advanced oxidation processes, either in single or in combination with other degradation techniques, can enhance the degradation of pharmaceuticals in aqueous solutions. Here, we review the degradation of pharmaceuticals by sonolysis, an oxidation processes using ultra-sound. In this technique, hydroxyl radicals are generated by pyrolytic cleavage of water molecules. We review the inuence of operational parameters, additives and hybrid techniques on the degradation of pharmaceuticals. The maximum degradation of organic compounds was observed in the frequency range of 1001000 kHz, which is in the high-frequency medium-power ultrasound. Even though almost all the experiments presented more than 90 % removal and good biodegradability of the target compound, good mineralization and the toxicity removal were hardly achieved. The efciency of the degradation varies with
water matrixes and varying pH. Major pathways of degradation are hydroxylation, dehalogenation, demethylation, decarboxylation, deamination, etc. More hybrid techniques have to be developed to scale up the application of ultrasound.
Keywords Emerging pollutants Pharmaceuticals
Advanced oxidation processes Sonolysis Cavitation
Degradation Mineralization
Introduction
Emerging contaminants are broad class of chemicals that are knowingly or unknowingly released to the environment, since these classes of pollutants are not fully covered by the existing water quality parameters, and therefore, most of their hazardous effects are not known. The different classes of emerging contaminants are pharmaceuticals and personal care products, endocrine disruptors, illicit drugs, industrial additives and agents, surfactants, gasoline additives, steroids and hormones, peruorinated compounds, ame retardants, as well as their transformation products and many other groups of nanoparticles (Farr et al. 2008; Richardson et al. 2007). Among these, the pollution of water bodies by pharmaceutically active...