Fluoride retention kinetic and equilibrium studies on layered double hydroxides under ambient conditions : Implications on pond-stream-hot spring-well water remediation
© 2022 Water Environment Federation.
| Veröffentlicht in: | Water environment research : a research publication of the Water Environment Federation. - 1998. - 94(2022), 11 vom: 02. Nov., Seite e10804 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2022
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| Zugriff auf das übergeordnete Werk: | Water environment research : a research publication of the Water Environment Federation |
| Schlagworte: | Journal Article calcination fluoride pollution hot spring fluoride layered double hydroxides multilayer retention Fluorides Q80VPU408O Hydroxides Water Pollutants, Chemical |
| Zusammenfassung: | © 2022 Water Environment Federation. Fluoride deficiency and toxicity severely affect a large population globally. Hence, a low-cost geosorbent is in demand to overcome fluorosis hazards where in situ retardation is prioritized over pilot-scale waste water treatment. This study reports the fluoride removal potential of MgFe-type layered double hydroxide (HT-LDH) and its calcined form at 500 and 800°C for their usability for treatment of polluted streams, ponds, wells, and hot spring water. Rapid uptake with >33% removal in 24 h was found by the adsorptive method, whereas the co-precipitation process removed >16 mg/L (>83%) in 1 h. The efficiency was further enhanced upon calcination at 500°C with >95% removal up to five times regeneration, unlike that at 800°C. It was demonstrated that multilayer sorption onto heterogeneous surface sites is majorly controlled by surface adsorptive and ion exchange mechanisms. Acidic pH, low aqueous F - , and temperature >25°C favored greater uptake, whereas competitive anions slightly enhanced its potential in the order N O 3 - > S O 4 2 - > P O 4 3 - in adsorptive removal. In the co-precipitation process, competing anions slightly hindered F - retention, whereas high temperature and low aqueous F - led to greater F - retention. No F-bearing solid phases were evidenced upon its retention, except lowering the HT-LDH crystallinity and rearrangement of C O 3 2 - surface functional groups. The fluoride contents of natural water were lowered drastically up to 77% in 60 min upon precipitation of HT-LDH by maintaining alkalinity and a di-/trivalent cationic ratio of 2.0. PRACTITIONER POINTS: F^- uptake is rapid on heterogeneous surface sites with multilayer sorption mechanism Greater F^- removed by coprecipitation technique compared with adsorptive pathway Acidic medium and temperature >25°C favor greater F^- retention NO_3^-+PO_l4^(3-) slightly enhanced F^- uptake by adsorption but lowered in coprecipitation Formation of LDH from natural waters lowered F^- content up to <77 |
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| Beschreibung: | Date Completed 10.11.2022 Date Revised 10.11.2022 published: Print Citation Status MEDLINE |
| ISSN: | 1554-7531 |
| DOI: | 10.1002/wer.10804 |