School of Physics and Electronic Information, Yan'an University, Yan'an 716000, China; Rhizosphere Biology Laboratory, Department of Microbiology, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620 024, India.
School of Physics and Electronic Information, Yan'an University, Yan'an 716000, China.
Environ Res. 2023 Oct 15;235:116558. doi: 10.1016/j.envres.2023.116558. Epub 2023 Jul 10.
Ciprofloxacin is one of the antibiotics predominantly used to treat bacterial infections, however excess usage, and release of antibiotic from various sources to the environment can cause severe risks to human health since it was considered as emerging pollutant. This study deals with the intimately coupled photocatalysis and biodegradation (ICPB) of ciprofloxacin using gCN/CdS photocatalytic semiconductor and eco-friendly renewable loofah sponge as biocarrier in the ICPB. The photocatalyst gCN/CdS was prepared and their synergistic photocatalytic degradation of ciprofloxacin were assessed and the results shows that gCN/CdS (20%) exhibit 79% degradation efficiency in 36 h. Further ICPB exhibited enhanced ciprofloxacin degradation 95% at 36 h. The 62.4% and 81.1% of chemical oxygen demand (COD) removal was obtained in the photocatalysis and ICPB respectively. Enhanced degradation of ciprofloxacin and COD removal was due to the synergetic photoelectrons generated from the gCN/CdS (20%) transferred to the bacterial communities which intensely mineralize the degradation products produced from the photocatalysis process. Furthermore, production of hydroxyl •OH and superoxide radical anion O• were identified actively involved in the degradation of ciprofloxacin. The biocarrier loofah sponge provided favourable environment to the bacterial communities for the formation of biofilm and production of extracellular polymeric substances (EPS). Excess quantity of EPS production in the ICPB helps in the prevention of toxicity of photocatalyst to bacterial communities as well as facilitate the extracellular electron transfer process. This work provides a novel path for enhanced degradation of ciprofloxacin using eco-friendly, low cost and renewable biocarrier loofah sponge in the ICPB system.
环丙沙星是一种主要用于治疗细菌感染的抗生素，然而，由于它被认为是一种新兴污染物，抗生素在各种来源中的过度使用和释放会对人类健康造成严重风险。本研究采用 gCN/CdS 光催化半导体和环保可再生丝瓜络作为生物载体，在 ICPB 中研究环丙沙星的紧密耦合光催化和生物降解（ICPB）。制备了光催化剂 gCN/CdS，并评估了它们对环丙沙星的协同光催化降解性能，结果表明，gCN/CdS（20%）在 36 h 内表现出 79%的降解效率。进一步的 ICPB 在 36 h 内表现出增强的环丙沙星降解 95%。光催化和 ICPB 分别获得 62.4%和 81.1%的化学需氧量（COD）去除率。环丙沙星和 COD 去除的增强降解是由于 gCN/CdS（20%）中产生的协同光电子转移到细菌群落，强烈矿化光催化过程中产生的降解产物。此外，鉴定出羟基•OH 和超氧自由基阴离子 O•积极参与了环丙沙星的降解。生物载体丝瓜络为细菌群落提供了有利的环境，有利于生物膜的形成和细胞外聚合物（EPS）的产生。ICPB 中过量的 EPS 产生有助于防止光催化剂对细菌群落的毒性，并促进细胞外电子转移过程。这项工作为使用环保、低成本和可再生生物载体丝瓜络在 ICPB 系统中增强环丙沙星的降解提供了一条新途径。
