Photodegradation of oxytetracycline in aqueous by 5A and 13X loaded with TiO2 under UV irradiation

The photocatalysis degradation, mineralization and detoxification of oxytetracycline (OTC) in aqueous were investigated by 5A and 13X zeolite with nano-TiO2 loaded under UV light. The composite photocatalysts are characterized by X-ray diffraction (XRD) and field emission scanning (FESEM) technologies. The adsorption isotherms of OTC by 5A and 13X with different pH are evaluated. The results show that 654 and 1497 mg/g OTC of saturation adsorption capacity is reached by 5A and 13X at pH 7, respectively. Then the effect of TiO2 with 5A and 13X support and different wt% of TiO2 over the support on the resultant OTC removal, net photocatalytic degradation and influence factors such as TiO2 loading, initial pH, concentration of OTC and adding anion on degradation are investigated. The 15 wt% TiO2/5A and 10 wt% TiO2/13X photocatalysts are found optimum for OTC removal and degradation in aqueous. The mineralization was measured by total organic carbon (TOC) while combined toxicity change during OTC degradation was tested with standardized bioluminescence assay of inhibition rate on Vibrio qinghaiensis sp.-Q67 (Q67). The results suggest that TiO2/5A and TiO2/13X composite systems are effective photocatalysts for treatment of OTC in aqueous. (C) 2009 Elsevier B.V. All rights reserved.