[Photodegradation of Ciprofloxacin Hydrochloride in the Aqueous Solution Under UV].

Effects of ciprofloxacin hydrochloride (CIP) initial concentration, Pb (NO3) 2, Cd (NO3) 2, PbCl2 and CdCl2 on the photodegradation of CIP using UV irradiation were investigated. The experiments results showed that UV irradiation could lead to effective removal of CIP, but there was no CIP degradation in dark. The photodegradation rate of CIP reduced with increasing initial concentration under UV irradiation. Pb(NO3)2 and Cd(NO3)2 (except for the experiment group of 0.006 mmol x L(-1)) could enhance CIP photodegradation, and the half-life of CIP gradually increased with increasing molar ratio between heavy metal and CIP ( with the decreasing concentration of nitrate). With increasing molar ratio (with the decreasing concentration of chlorate), PbCl2 and CdCl2 first promoted and then inhibited the CIP photodegradation.

[Natural attenuation of tetracycline in the water of Taihu Lake under different environmental conditions].

Tetracycline (TC) has been widely used in veterinary medicines and disease treatments, and has been discharged into nature system due to manure application. To know the harmfulness of TC residues, and to investigate the natural attenuation of TC under different environmental conditions, simulated attenuation experiments in the presence of light, sediment, Cd (NO3) 2 and Pb(NO3)2 were performed. Results showed that the natural attenuation of TC was not obvious under the sunlight, and the natural attenuation rate of TC in water with unsterilized sediment was greater than that with sterilized sediment. The natural attenuation of TC in water with Pb(NO3)2 was slow at the first stage of the experiment, and progressively speeded up as time went on. However, the natural attenuation of TC in water with Cd(NO3)2 was more rapid at the beginning, and significantly faster than that of Pb(NO3)2. The natural attenuation rates of 0.08 mmol x L(-1) TC under different conditions follow the sequence: unsterilized sediment (87.2%) > sterilized sediment (70.37%) > Cd(NO3)2 (64.2%) > Pb(NO3)2 (32.3%) > blank (6.6%), suggesting that all these factors can promote the natural attenuation of TC. Though the natural attenuation trend under different conditions in the dark is similar to that under the sunlight, the natural attenuation rate is less than that under the sunlight, which implicates that sunlight may promote the natural attenuation of TC.