Photocatalytic Degradation and Drug Activity Reduction of Chlorampenicol

Available at www.sciencedirect.com jo ur na l ho me pa ge : ww w. el se vi er .com /l oc at e/ wa tr es Photocatalytic degradation and drug activity reduction of Chloramphenicol A. Chatzitakis a , C. Berberidou a , I. Paspaltsis b , G. Kyriakou c , T. Sklaviadis b , I. Poulios a, a Laboratory of Physical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece b Prion Disease Research Group, Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece c Laboratory of Inorganic Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece a r t i c l e i n f o Article history: Recei ved 1 May 2007 Received in revised form 26 June 2007 Accep ted 18 July 2007 Available online 27 July 2007 Keywords: Photocatalysis Chloramphenicol Photo-oxidation Drugs ZnO TiO 2 a b s t r a c t The photoc atal yti c deg radation of Chlora mpheni col , an antibiotic drug, has bee n investigated in aqueous heterogeneous solutions containing n-type oxide semiconductors as photocatalysts. The disappearance of the organic molecule follows approximately a pseudo-first-order kinetics according to the Langmuir–Hinshelwood model. It was observed that, with TiO 2 P-25 as photocatalyst, quantitative degradation of the organic molecule occu rs after 4 h of illuminatio n. During this time, the dechlorin ation of the substrate is complete, while the organic nitrogen was recovered in the form of nitrate and ammonium ions. The effect of temperature on the degradation rate of Chloramphenicol shows similar appa rent act iva tio n ene rgi es for bot h TiO 2 P-25 and ZnO photocatal ysts . The initial apparent photonic efficiency (z 0 ) of the photo-ox idatio n and the mineralizat ion under various experimental conditions have been calculated, whil e the Kirby–Bauer disc diffusion met hod showe d a 100% reduct ion of the drug act ivi ty afte r 90 min of photoc atal yti c treatment. & 2007 Elsevier Ltd. All rights reserved. 1. Introduction Altho ugh pharmaceuti cals have been consumed for many decades, only during the last few years their fate and release in the aquatic environment have been recognized as one of the most urgent que sti ons of env ir onme nta l chemist ry . Current drinking water standards do not even require testing for any of the more than 7000 pharmaceutical compounds being prescribed. Pharmaceutically active compounds such as analg estics, antibiotics, stero id, hormon es, etc., have been detected in several public water systems in Europe, USA and Australia as a result of human, animal and plant activities (Ajit et al., 2006; Kolpin et al., 2002). Mass balance of the input and output of pharmaceuticals in sewage treatment plants indicates that during sewage treatment not all pharmaceuticals ar e removed qua nti tat ive ly (Heber er, 2002 ), and in surface and underground water, they are detected at times. Their envi ronmentalpresence gains importance bec ause the y are related abnormal physiological processes in reproduction, increased incid ences of cancer, dev elopment of antibiotic- resistant bacteria and potential increased toxicity of chemical mixtures. For many substances, the potential effects on hu- mans and aquatic ecos yst ems ar e not cle ar ly understood (Halling-Sorensen et al., 1998). As a consequence, several efforts are being made to find out ways of inactivating or eliminating this class of substances in surface or wastewater. Among the so-called advanced oxidation processes, homo- geneous and hetero geneous photocatal ytic oxida tion have shown, recently, great promise in the treatment of industrial wastewater, groundwater and contaminated air. AR TIC LE IN PR ESS 0043-13 54/$ - see front ma tter & 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.watres.2007.07.030 Corresponding author. T el.: +3 0 2310 997785; fax: +302310 997784. E-mail address: [email protected] (I. Poulios). WATER RESEARCH 42 (2008) 386– 394

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Photocatalytic Degradation and Drug Activity Reduction of Chlorampenicol