基于g-C3 N4研究环境中甲氧苄啶的光降解行为及其毒性

为研究残留抗生素在不同环境介质中的可见光降解行为特征，借助非金属和生物相容的石墨相氮化碳（g-C₃N₄）构建恒温恒湿和快速模拟可见光降解的实验环境，考察甲氧苄啶（TMP）进入不同环境（水、大气颗粒物和土壤）中的光降解过程与机制，并深入探讨TMP降解前后毒性变化规律.结果表明，用氙灯模拟太阳光和g-C₃N₄共存下，水、大气颗粒物和土壤中TMP经光照3 h后降解率分别为89.2%、35.8%和16.9%，同时发现参与水体TMP光降解的主要活性物质是·OH，而在大气颗粒物和土壤介质中光降解过程主要受·O₂^-控制.与大气颗粒物、土壤相比，水中TMP光解后可生成较为稳定的羰基化中间产物（m/z，305），水生毒性试验结果表明TMP光解产物对斜生栅藻表现出较原药更强的毒性，可显著抑制藻细胞生长率、叶绿素a和b的含量，并引起细胞氧化应激.

Photodegradation Behaviors and Toxicity Characteristics of Trimethoprim into Different Environmental Media with the Presence of g-C3N4

To investigate the photochemical behaviors of antibiotic residues in different environmental media, this study examined the photodegradation characteristics of trimethoprim (TMP) in water, atmospheric particulate matter, and soil under the coexistence of graphite carbon nitride (g-C₃N₄) and further evaluated its aquatic toxicity variation before and after visible light degradation. The results showed that the degradation rates of TMP separately reached 89.2%, 35.8%, and 16.9% in water, atmospheric particulate matter, and soil. Free radical trapping experiments found that·OH played an important role during the photodegradation process in water, whereas·O₂^- was shown to be the dominant active species in atmospheric particulate matter and soil. The photodegradation of TMP in water generated more stable carbonylation intermediates (m/z, 305), unlike the processes in soil and atmospheric particulates. Further aquatic toxicity tests demonstrated that photodegradation products of TMP showed stronger toxicity to Scenedesmus obliquus than the original TMP, which significantly inhibited the growth rate of algal cells and the contents of chlorophyll a and b and caused cellular oxidative stress.