Performance of Rod-Shaped Ce Metal-Organic Frameworks for Defluoridation

• Published in: Molecules (Basel, Switzerland) Vol. 28; no. 8; p. 3492
• Main Authors: Song, Jiangyan, Yang, Weisen, Han, Xiaoshuai, Jiang, Shaohua, Zhang, Chunmei, Pan, Wenbin, Jian, Shaoju, Hu, Jiapeng
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 15.04.2023; MDPI
• Subjects: Acids; Adsorbents; Adsorption; Alzheimer's disease; Aqueous solutions; Ce-H3TATAB-MOFs; Chemisorption; China; Composite materials; Drinking water; Efficiency; Electrostatic properties; fluoride; Fluorides; Fluorine; Functional groups; Influence; Kinetics; Ligands; Membrane separation; Metal-organic frameworks; Metals; Physical characteristics; Pollutants; Pore size; s-triazines; Sorption; Thermodynamics; Triazine; Water pollution; X ray photoelectron spectroscopy; China; Ce-H3TATAB-MOFs; fluoride; adsorption; metal–organic frameworks
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28083492

The performance of a Ce(III)-4,4',4″-((1,3,5-triazine-2,4,6-triyl) tris (azanediyl)) tribenzoic acid-organic framework (Ce-H3TATAB-MOFs) for capturing excess fluoride in aqueous solutions and its subsequent defluoridation was investigated in depth. The optimal sorption capacity was obtained with a metal/organic ligand molar ratio of 1:1. The morphological characteristics, crystalline shape, functional groups, and pore structure of the material were analyzed via SEM, XRD, FTIR, XPS, and N adsorption-desorption experiments, and the thermodynamics, kinetics, and adsorption mechanism were elucidated. The influence of pH and co-existing ions for defluoridation performance were also sought. The results show that Ce-H3TATAB-MOFs is a mesoporous material with good crystallinity, and that quasi-second kinetic and Langmuir models can describe the sorption kinetics and thermodynamics well, demonstrating that the entire sorption process is a monolayer-governed chemisorption. The Langmuir maximum sorption capacity was 129.7 mg g at 318 K (pH = 4). The adsorption mechanism involves ligand exchange, electrostatic interaction, and surface complexation. The best removal effect was reached at pH 4, and a removal effectiveness of 76.57% was obtained under strongly alkaline conditions (pH 10), indicating that the adsorbent has a wide range of applications. Ionic interference experiments showed that the presence of PO and H PO in water have an inhibitory effect on defluoridation, whereas SO , Cl , CO , and NO are conducive to the adsorption of fluoride due to the ionic effect.