TiO2 photocatalytic degradation of tetracycline as affected by a series of environmental factors

TiO2 photocatalytic degradation of tetracycline (TC) in aqueous solution under UV irradiation was investigated as affected by different environmental factors, including cations, anions, organic acids, and surfactants. The solution of TC with TiO2 was irradiated by medium mercury lamp. The concentrations of TC and metal ions were analyzed by HPLC and AAS, respectively. The degradation efficiency of TC was calculated based on TC disappearance. Photocatalysis was very effective for TC removal. The degradation efficiency of TC was significantly enhanced in the presence of Cu2+/Pb2+, SO4 (2-)/Cl-, and humic acid (HA) in the examined range, but did no change with Ni2+, Cd2+, or Zn2+. In addition, the results also showed that solution Cu2+ and Pb2+ ions could be reduced during the process, while Ni2+, Cd2+, and Zn2+ were still kept in the solution. However, tannic acid (TA), gallic acid (GA), citric acid (CA), salicylic acid (SA), hydroxypropyl-beta-cyclodextrin (HPCD), polyoxyethylene lauryl ether (Brij35), or polyoxyethylenesorbitan monooleate (Tween80) significantly decreased the degradation efficiency of TC. The photocatalytic approach could be successfully applied to remove TC, and environmental factors significantly influenced its degradation efficiency. It would be useful to understand the environmental behaviors of TC and for the implementation of remediation strategies of TC.