Enhanced photocatalytic disinfection of Escherichia coli K-12 by porous g-C3N4 nanosheets: Combined effect of photo-generated and intracellular ROSs
Enhanced photocatalytic disinfection of Escherichia coli K-12 by porous g-C3N4 nanosheets: Combined effect of photo-generated and intracellular ROSs
复制标题
多孔 g-C3N4 纳米片增强对大肠杆菌 K-12 的光催化消毒：光生活性氧和细胞内活性氧的综合作用
DOI：
10.1016/j.chemosphere.2019.07.007
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发表时间：
2019-11-01
期刊：
影响因子：
8.8
通讯作者：
Jiang, Fang
中科院分区：
文献类型：
--
作者：
He, Nannan;Cao, Shihai;Jiang, Fang
采用一步化学剥离法高产率地合成了多孔石墨化碳氮化纳米片(PCNSS)。与块体石墨化碳氮化物相比，PCNSS加速了光生电子-空穴对的分离效率。在模拟太阳光照射下，PCNS5(剥离5h)对大肠杆菌K-12具有最好的光催化杀菌能力，在2 h内对6.5log(10)cfu/mL的大肠杆菌K-12进行完全杀菌，其光催化活性的提高源于介孔纳米片状结构。光催化消毒的可能机制是提高了细胞内的活性氧水平和抗氧化酶(如过氧化氢酶和超氧化物歧化酶)的活性。在光催化消毒过程中观察到的透射电子显微镜图像表明，细胞膜被认为是氧化的第一目标，导致细胞质内容物更快地泄漏，最终导致DNA降解，导致细菌死亡。此外，捕获实验表明，超氧阴离子自由基(中心点O-2(-))和空穴(h(+))是PCNS5杀灭大肠杆菌K-12的主要原因。(C)2019爱思唯尔有限公司。保留所有权利。
The porous graphitic carbon nitride nanosheets (PCNSs) with high yields were synthesized by using one-step chemical exfoliation method. PCNSs accelerated separation efficiency of photo-generated electron-hole pairs in comparison to bulk graphitic carbon nitride. The PCNS5 (exfoliation for 5 h) exhibited optimal photocatalytic disinfection capability towards Escherichia coli K-12 under simulated solar light irradiation with complete disinfection of 6.5 log(10) cfu/mL of E. coil K-12 within 2 h. The enhanced photocatalytic activity of PCNS5 originated from mesoporous nanosheet structure. The possible mechanism of photocatalytic disinfection has proposed that intracellular reactive oxygen species levels and the activities of antioxidant enzymes (e.g., catalase and superoxide dismutase) were enhanced. Transmission electron microscope images observed during photocatalytic disinfection process suggested that the cell membrane was regarded as the first target for oxidation, resulting in a faster leakage of cytoplasmic content and finally degradation of DNA leading to bacterial death. Furthermore, the trapping experiment showed that superoxide radical (center dot O-2(-)) and holes (h(+)) were responsible for E. coli K-12 disinfection by PCNS5. (C) 2019 Elsevier Ltd. All rights reserved.