Comparative study of the abatement of elevated fluoride in groundwater from Vea catchment in the Upper East Region of Ghana using bone char and thermally activated bone char
Abstract Fluoride ion (F−) concentration between 0.5 to 1.5 mg/L in drinking water can be good for human health and above the range can be harmful according to the World Health Organization. This work seeks to abate groundwater with F− concentration of 3.10 mg/L from Vea catchment in the Upper East...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Springer
2025-07-01
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| Series: | Discover Water |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s43832-025-00241-x |
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| Summary: | Abstract Fluoride ion (F−) concentration between 0.5 to 1.5 mg/L in drinking water can be good for human health and above the range can be harmful according to the World Health Organization. This work seeks to abate groundwater with F− concentration of 3.10 mg/L from Vea catchment in the Upper East Region of Ghana, using bone char (BC) and thermally activated bone char (ABC) as cost-effective adsorbents for rural areas like the study area in a comparative study. The bone char and thermally activated bone char were produced from waste cattle bones in a gas-fired static bed pyrolysis/activation reactor that was developed locally at carbonization and activation temperatures of 900 °C and 1000 °C, respectively, with steam as the activating agent at a flow rate of 4 mL/min. Both BC and ABC were contacted with F− contaminated groundwater. The adsorption process was fitted to pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetics, likewise the Langmuir and Freundlich isotherms. Scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM/EDS) analysis shows a fluffy and spongy surface with little or poor pore development for BC and moderate pore development for ABC, with the EDS showing hydroxyapatite components necessary for fluoride removal. The BC reduced F− concentration from 3.10 to 0.8 mg/L, representing 74% removal efficiency, while ABC reduced it to 2.9 mg/L representing 7% removal efficiency, after half an hour. The PFO kinetic model indicated that the adsorption of F− with ABC was a diffusion control, while the PSO kinetic model indicated that the adsorption of BC was chemisorption. The Freundlich adsorption isotherm, which shows a multilayer and advantageous adsorption of F− on heterogeneous surface sites, was well fitted by the adsorption process. As a result, this study has demonstrated the effectiveness of BC in removing F− from groundwater in the Vea catchment, with faster kinetics as compared to the slow removal rate of ABC. Unlike previous studies where activation has been emphasized, this study has shown that there is no need for BC activation since the charred bone was more efficient in reducing the F− concentration within 1 h below the WHO standard compared to ABC, contributing to a significant reduction in energy consumption for BC adsorbent production for F−removal during the carbonization process. |
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| ISSN: | 2730-647X |