engleski

EVIRONMENTAL ASPECT OF PHOTOCATYLISIS FOR THE DEGRADATION OF OXYTETRACYCLINE IN WATER: N-S-TiO2 vs TiO2

Antibiotics are among the most commonly used pharmaceutical in human and veterinary medicine and have increasingly become a problem for the environment. Oxytetracycline (OTC) is a broad-spectrum antibiotic belonging to the tetracycline class and due to its antibiotic nature, stable naphthalene ring structure and hydrophilic properties, its removal by conventional wastewater treatments is difficult.[1] On the other hand, titanium dioxide is one of the most studied semiconductors in photocatalytic processes for water treatment due to its unique properties such as chemical inertness, photostability and biocompatibility.[2] One of the major drawbacks of TiO2 as a photocatalyst is the wide band gap (3.2 eV) of the material, which limits the light absorption only to the ultraviolet region (wavelength <390 nm), thus limiting the practical applications for solar light harvesting.[3] Doping TiO2 with metal, non-metal, or co- doping increases its photocatalytic activity under a broader solar spectrum. In this sense, nitrogen and sulphur have been found to be effective doping elements to enhance the photocatalytic activity under visible light illumination.[4] In this work Sulphur- and Nitrogen-dope TiO2 (S-N-TiO2) photocatalyst and benchmark TiO2 P25 have been employed for the degradation of OTC under solar and visible irradiation at three pH, corresponding with OTC pKa values (3.2, 7.5 and 8.9). OTC concentration, mineralization, degradation by-products, and associated changes in biodegradability and toxicity (A. fishery, D. Magna and P. Subcapitata) were monitored during the treatment.

Water treatment, photocatylisis, oxytetracycline, nitrogen-dope titanium dioxide

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