Tetracyclines (TCs) are a successful class of antibiotics used globally. They are used for veterinary purposes, for human therapy and also as pharmaceuticals to control plant bacterial infections. Chlortetracycline (CTC), oxytetracycline (OTC) and tetracycline (TC) are the most widely used of this broad group. Of these, OTC is the most effective in plant disease control. In the USA, OTC is used primarily on pear and apple for fire blight management. TCs are not toxic; however, their presence in the environment, even at traces levels, can promote resistance of microorganisms. Till now, wastewater treatment plants are not capable of removing TCs efficiently. Advanced oxidation processes (AOPs) have shown to be effective in the degradation of organic pollutants, especially gamma radiation technology. Data regarding the application of AOPs to TCs removal is limited. Therefore, the aim of this study is to assess the effectiveness of these AOPs in the degradation of TCs using gamma irradiation. Focus is given to the influence of absorbed dose and the effect of radical species on the degradation of TCs. The results show that the concentration of the studied TCs decreases at higher absorbed doses and the decrease is less pronounced with aerated solutions. This behavior is probably a consequence of the scavenging of e-aq and H� by O2 leading to a decrease in the degradation efficiency of the TCs. The results also show that the degradation of OTC and TC is higher in the presence of N2O, while for CTC the degradation is favored under N2. This is a potential indication that the OH� is one of the reactive species responsible for OTC and TC degradation, whereas for CTC the main contribution probably comes from e-aq and H�.

Degradation of tetracyclines by gamma irradiation advanced oxidation processes (AOPs): Influence of the different radical species and the absorbed dose

248th National Meeting (2014)

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