Photodegradation of tetracyclines compound in aqueous solution under different light irradiation
水中四环素类化合物在不同光源下的光降解

The aquatic photochemical behaviors of tetracyclines(TCs) were investigated under the simulated and natural sunlight.The results indicated that TCs were directly degraded under the simulated sunlight.Moreover,the TCs’ photodegradation efficiency changed as the solution pH.The photodegradation of tetra cycline(TC),oxytetracycline(OTC),chlortetracycline(CTC),and doxycycline(DTC) increased with the increase of pH,whereas the minocycline(MTC) photodegradation exhibited different trend.In the pH range of natural water,the reaction rate constants of TCs ranged from 0.004～0.026 min-1,and the half-lives of photodegradation of TCs ranged from 26～136 min under simulated sunlight.The direct photodegradation rate of TCs is proportional to the sunlight intensity.Photolysis of TCs under sunlight irradiation at different season showed that the degradation is faster in summer compared with that in spring/winter.The photodegradation of tetracycline in Dongjiang River showed a fast rate.The average half-lives of TC was 8.2 min in clear weather of winter.