不同源胡敏酸对磺胺嘧啶紫外光降解的影响及作用机制

研究了紫外光照条件下不同来源的胡敏酸（HA），包括标准品胡敏酸（SPHA）、水稻土胡敏酸（SDHA）、泥炭土胡敏酸（NTHA）和落叶覆盖地胡敏酸（LYHA）对抗生素磺胺嘧啶（SDZ）光降解的影响以及主要活性物种对其光降解效能的贡献.结果表明：SDZ在纯水中及与HA共存条件下，其光降解过程均符合一级动力学模型，且HA对SDZ的光降解具有促进作用，其促进效果从大到小为SPHA > SDHA > NTHA > LYHA.通过羟基自由基（·OH）和单线态氧（¹O₂）淬灭实验发现，不同来源HA产生·OH和¹O₂的能力具有一定差异性.同等背景条件下，SPHA产生的·OH量相对较多，其对SDZ光降解的贡献率（26.97%）最大，而LYHA贡献相对较小（9.33%）.同时，¹O₂对SDZ光降解起主导作用，其降解贡献率为41.33%~51.95%.

Influence and mechanism of humic acid from different sources on ultraviolet photodegradation of sulfadiazine

The effects of different humic acids (HA), including standard humic acid (SPHA), Paddy soil humic acid (SDHA), Peat soil humic acid (NTHA) and Deciduous soil humic acid (LYHA), on the photodegradation of sulfadiazine (SDZ), and corresponding contribution of primary reactive species was investigated. The results indicated that the photodegradation process of SDZ in pure water and HA solution was consistent with the first-order photodegradation kinetic model. The photodegradation of SDZ was promoted by HA, in order of promoting effects:SPHA > SDHA > NTHA > LYHA. Based on the quenching experiment of hydroxyl radical (·OH) and singlet oxygen (¹O₂), the capacity to produce·OH and ¹O₂ of HA was been influenced by its own source. Under the same conditions, the amount of·OH produced by SPHA was relatively higher, and its contribution rate to SDZ photodegradation was the largest (26.97%), while LYHA contribution was relatively smaller at 9.33%. Meanwhile, ¹O₂ was found to play the most important role in the photodegradation of SDZ, with the contribution rate ranging from 41.33% to 51.95%.