Zhong Keng-Qiang, Xie Dong-Hua, Liu Yan-Jun, Guo Pu-Can, Sheng Guo-Ping
CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei 230026, China.
Water Res X. 2023 Aug 4;20:100193. doi: 10.1016/j.wroa.2023.100193. eCollection 2023 Sep 1.
The efficient generation and utilization of ROSs is a key step in determining the achievement of safe drinking water by photocatalytic bacterial inactivation technology. Although graphitic carbon nitride (g-CN) serves as a green and promising photocatalyst for water disinfection, insufficient bacterial capturing capacity and serious charge recombination of pristine g-CN extremely restrict its bactericidal activity. Herein, we develop a facile thermal exfoliation and thermal polymerization method to prepare the nitrogen-defective ultrathin g-CN nanosheets (DUCN-500). Our results showed that ultrathin nanosheet structure greatly enhanced bacterial capturing capacity of g-CN to increase the utilization efficiency of ROS, which contributed to the performance of DUCN-500 greatly outperforming bulk g-CN. The nitrogen defects increased ROS generation (·O and HO) by approximately 4.6 times, which was attributed to negative shift of the conduction band potential and rapid separation of charge carriers. The DUCN-500 could rapidly and completely inactivate and in real sewage under simulated solar irradiation, accompanied by good anti-interference capability and stability. Additionally, bacterial morphology destruction, the loss of antioxidant enzyme activity and the leakage of protein were proven to be the main mechanisms of photocatalytic sterilization. This study offers new insight into the rational design of efficient g-CN-based photocatalysts for water disinfection.
活性氧物种（ROSs）的高效生成与利用是决定光催化细菌灭活技术实现安全饮用水的关键步骤。尽管石墨相氮化碳（g-CN）作为一种用于水消毒的绿色且有前景的光催化剂，但原始g-CN的细菌捕获能力不足和严重的电荷复合极大地限制了其杀菌活性。在此，我们开发了一种简便的热剥离和热聚合方法来制备氮缺陷超薄g-CN纳米片（DUCN-500）。我们的结果表明，超薄纳米片结构极大地增强了g-CN的细菌捕获能力，从而提高了ROS的利用效率，这使得DUCN-500的性能大大优于块状g-CN。氮缺陷使ROS生成（·O和HO）增加了约4.6倍，这归因于导带电位的负移和电荷载流子的快速分离。在模拟太阳辐射下，DUCN-500能在实际污水中快速且完全地灭活 ，并具有良好的抗干扰能力和稳定性。此外，细菌形态破坏、抗氧化酶活性丧失和蛋白质泄漏被证明是光催化杀菌的主要机制。本研究为合理设计用于水消毒的高效g-CN基光催化剂提供了新的见解。
