磺胺氯哒嗪在海水中的间接光降解

以有色溶解有机物(CDOM)作为主要光敏剂研究磺胺氯哒嗪(SCP)间接光降解行为和机理,分析CDOM组成、盐度和pH值对SCP间接光降解的影响.SCP间接光降解速率随CDOM浓度升高而逐渐加快.CDOM产生的光化学反应活性中间体对SCP间接光降解的贡献率不同,其中³CDOM^*起主要作用,对SCP间接光降解的贡献率高达77.94%.所用CDOM由4种荧光组分组成,包含3种外源腐殖质(C1,C2,C3)和1种内源腐殖质(C4), SCP间接光降解去除率和³CDOM^*浓度分别与荧光组分的相关性大小顺序均为C3>C2>C4>C1.其中C3和C2与³CDOM^*]具有较高线性相关性(R²>0.97),是³CDOM^*的主要贡献者.盐度和pH值对SCP间接光降解的影响作用显著.在盐度为15‰时,SCP的间接光降解速率最大.在低盐度范围(0~15‰)内,离子强度效应对间接光降解的促进作用大于无机阴离子带来的抑制作用,使得间接光降解速率随着盐度的升高而加快.溶液pH=(5.00±0.10)时,SCP的间接光降解速率最大.SCP的间接光降解速率随着溶液pH值的升高而减慢,中性和碱性环境不利于SCP的间接光降解.

The indirect photodegradation of sulfapyridazine in seawater

The indirect photodegradation behavior and mechanism of SCP were studied by using CDOM that as the main photosensitizer. The effects of CDOM composition, salinity and pH on indirect photodegradation of SCP were analyzed. When CDOM concentration increased, the indirect photodegradation rate of SCP accelerated obviously. Upon irradiation, CDOM produced a variety of active substances, and the different active substances had different contribution rates to the indirect photodegradation of SCP, especially the ³CDOM^* played a major role in the indirect photodegradation of SCP and its contribution rate was up to 77.94%. The CDOM used in the experiment was composed of four components, including three terrestrial humus (C1, C2, C3) and the marine humus (C4). The order of the correlation between the SCP removal rates and the four fluorescence components was C3>C2>C4>C1. The correlation between four fluorescence components and ³CDOM^*] were also ranked as the former. C3 and C2 components had a significant correlation with ³CDOM^*] (R²>0.97), that demonstrated the C3 and C2 components made great contributions to the production of ³CDOM^*]. Salinity and pH value had significant effects on indirect photodegradation of SCP. When the salinity of the solution was equal to 15‰, the SCP indirect photodegradation rate reached a maximum. In the low salinity range (0~15‰), the promotion effect of ionic strength was greater than the inhibition effect of inorganic anions that made the indirect photodegradation rate greater with the increase of salinity. When the pH of the solution was equal to (5.00±0.10), the SCP indirect photodegradation rate reached a maximum. The indirect photodegradation rate of SCP slowed down with the increase of pH value of the solution, and the neutral and alkaline environments had negative effects on the indirect photodegradation of SCP.