[Photodegradation performance and mechanisms of carbamazepine and its impact factors]

The photodegradation performance and mechanisms of carbamazepine (CBZ) in pure water were investigated in simulated irradiation using a 300 W Xenon lamp. Batch experiments were carried out to explore the influences of nitrate (NO3(-)), bicarbonateradical (HCO3(-)) and humic acid (HA) on CBZ's photodegradation. The results demonstrate that the photodegradation of CBZ in pure water follows a pseudo-first-order kinetics. When the irradiation intensity was 1200 mW x cm(-2) and the initial concentration of CBZ was 200 microg x L(-1), the CBZ's photodegradation rate constant and half-life were 0.028 7 min(-1) and 24.15 min, respectively. Sensitization degradation gave the priority to the photodegradation of CBZ, and the contribution of singlet oxygen (1O2) was 75.3% which was higher than hydroxyl radical (*OH) of 5.6%. Under the conditions of this study, the increase of NO3(-), HCO3(-) and HA concentration inhibited CBZ's photodegradation. Among of which, the inhibition effect of NO3(-) on CBZ's photodegradation was the most significant. When the concentration of NO3(-) was up to 0.5 mmol x L(-1), the half-life of CBZ was prolonged to 433.22 min, which was 18 times as that in pure water without NO3(-).