GO-CeO₂ nanohybrid for ultra-rapid fluoride removal from drinking water
GO-CeO₂ nanohybrid for ultra-rapid fluoride removal from drinking water
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GO-CeO™ 纳米混合物可超快速去除饮用水中的氟化物
DOI：
10.1016/j.scitotenv.2021.148547
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发表时间：
2021
影响因子：
9.8
通讯作者：
Bezbaruah, Achintya N.
中科院分区：
文献类型：
--
作者：
Rashid, Umma S.;Das, Tonoy K.;Sakthivel, Tamil S.;Seal, Sudipta;Bezbaruah, Achintya N.
饮用水中过量的氟(F−>；1.5 mg/L)影响着全球2.6亿多人，并导致牙齿和骨骼氟中毒等健康问题。本研究考察了氧化石墨烯-氧化铈纳米杂化材料(GO-CeO2)的除氟性能，并探讨了其除氟机理。该纳米杂化材料表现出超快的除氟动力学，在1min内达到平衡(85%的去除，10mgF−/L初始浓度)，这是迄今报道的最快的除氟动力学之一。纳米杂化材料对氟的吸附符合朗缪尔等温式，在pH为6.5时最大吸附容量为8.61 mg/g，当pH降至4.0时，吸附容量增加到16.07 mg/g。根据实验结果和表征数据，我们推测除氟过程中既有静电相互作用，又有表面络合作用。CeO2晶格中的O2-−离子被F-−离子取代形成配合物(络合物)。当Ce4+和Ce3+同时存在于纳米CeO2中时，Ce3+参与了氟离子的络合作用。在GO-CeO2除氟过程中，GO膜起到电子介体的作用，有助于将CeO2NPs-GO界面上的Ce4+还原为Ce3+，而Ce3+对纳米杂化材料的除氟有促进作用。
The presence of excess fluoride (F−> 1.5 mg/L) in drinking water affects more than 260 million people globally and leads to dental and skeletal fluorosis among other health problems. This study investigated fluoride removal by graphene oxide-ceria nanohybrid (GO-CeO2) and elucidated the mechanisms involved. The nanohybrid exhibited ultra-rapid kinetics for fluoride removal and the equilibrium (85% removal, 10 mg F−/L initial concentration) was achieved within 1 min which is one of the fastest kinetics for fluoride removal reported so far. Fluoride removal by the nanohybrid followed Langmuir isotherm with a maximum adsorption capacity of 8.61 mg/g at pH 6.5 and that increased to 16.07 mg/g when the pH was lowered to 4.0. Based on the experimental results and characterization data, we have postulated that both electrostatic interaction and surface complexation participated in the fluoride removal process. The O2−ions present in the CeO2lattice were replaced by F−ions to make a coordination compound (complex). While both Ce4+and Ce3+were present in ceria nanoparticles (CeO2NPs), Ce3+participated in fluoride complexation. During fluoride removal by GO-CeO2, the GO sheets acted as electron mediators and help to reduce Ce4+to Ce3+at the CeO2NPs-GO interface, and the additional Ce3+enhanced fluoride removal by the nanohybrid.