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Efficient groundwater defluorination over a wide concentration gradient through capacitive deionization with a three-layer structured membrane coating electrode.
- Source :
-
Journal of Hazardous Materials . Jan2024, Vol. 462, pN.PAG-N.PAG. 1p. - Publication Year :
- 2024
-
Abstract
- Fluoride (F−) pollution in groundwater is an important environmental issue and capacitive deionization (CDI) holds promise for defluorination at moderate concentrations (e.g., 200 −1000 mg L−1). However, existing electrodes suffer from the overlap of electrical-double-layer (EDL) and severe co-ion effects at low (e.g., <200 mg L−1) and high sodium fluoride (NaF) concentrations (e.g., >1000 mg L−1), respectively, exhibiting poor salt adsorption capacity (SAC). Hence, a three-layer structured electrode, "membrane/carbon nanotube (CNT)/activated carbon (AC)" (CNT-MCE), was prepared through electrospinning CNT onto AC, followed by a polymer membrane coating. Compared to AC and membrane coated electrode, CNT-MCE with mesopore-dominated structure prevented EDL overlap, achieving a higher SAC of 40.8 mg g−1 at 100 mg L−1 NaF. At 1500 mg L−1 NaF, the positively charged CNT-MCE exhibited an improved SAC of 58.8 mg g−1 by inhibiting co-ion effects. Meanwhile, CNT-MCE consistently demonstrated superb SACs at 200 − 800 mg L−1 NaF and maintained excellent stability over a wide concentration gradient by inhibiting severe oxidation. Notably, CNT-MCE successfully decreased the F− concentration in simulated groundwater from 3.4 to 1.1 mg L−1. Overall, our work provides an efficient strategy of electrode design to broaden the applicability of CDI for groundwater defluorination over a wide concentration gradient. [Display omitted] • Three-layer structured membrane coating electrode was prepared for F- removal. • High F- adsorption capacities were obtained over the wide concentration gradient. • Mesopore-dominated structure overcame the overlapping of electrical double layer. • Positively charged polymer membrane inhibited the serious co-ion repulsion effect. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03043894
- Volume :
- 462
- Database :
- Academic Search Index
- Journal :
- Journal of Hazardous Materials
- Publication Type :
- Academic Journal
- Accession number :
- 173807632
- Full Text :
- https://doi.org/10.1016/j.jhazmat.2023.132703