以氙灯为模拟光源,研究了酰胺咪嗪(carbamazepine,CBZ)在纯水中的光降解效能与机制,并考察了硝酸根离子(NO3-)、碳酸氢根离子(HCO3-)和腐殖酸(HA)对其光降解速率的影响.结果表明,纯水中CBZ的光降解符合假一级反应动力学;在光强为1 200 mW.cm-2、CBZ初始浓度为200μg·L-1时,CBZ的光降解速率常数为0.028 7 min-1,半衰期为24.15min;纯水中CBZ的去除是以自敏化光降解反应为主,其中单线态氧(1O2)参与的自敏化光氧化反应贡献率较大,为75.3%,而羟基自由基(.OH)的贡献率较小,为5.6%;在本试验条件下,NO3-、HCO3-以及HA浓度的增加都会对CBZ的光降解过程产生抑制,其中NO3-的抑制作用最为明显,当加入的NO3-浓度为0.5 mmol·L-1时,CBZ的半衰期延长为433.22 min,约为不加NO3-时的18倍.
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(NO-3),bicarbonateradical(HCO-3) 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 1 200 mW·cm-2 and the initial concentration of CBZ was 200 μg·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(1 O2) was 75.3% which was higher than hydroxyl radical(·OH) of 5.6%.Under the conditions of this study,the increase of NO-3,HCO-3 and HA concentration inhibited CBZ's photodegradation.Among of which,the inhibition effect of NO-3 on CBZ's photodegradation was the most significant.When the concentration of NO-3was up to 0.5 mmol·L-1,the half-life of CBZ was prolonged to 433.22 min,which was 18 times as that in pure water without NO-3.