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NATH & DUTTA: FLUORIDE REMOVAL FROM WATER USING CRUSHED LIMESTONE 121 low cost method of fluoride removal which uses lime and alum also suffers from some disadvantages, viz., it adds toxic ...
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Pre-acidified fluoride water using two edible acids, viz., acetic acid (AA) and citric acid (CA) have been used for treatment by crushed limestone of diameter 3-4 mm to precipitate fluoride...
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Fluoride Removal by Calcite. As described above, the most common materials used for defluoridation are lime and limestone. Nevertheless, processed lime (CaO) and hydrated lime (Ca (OH) 2) are …
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In this study, fluoride removal by crushed limestone (99% pure calcite) was investigated by batch studies and surface-sensitive techniques from solutions with …
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Code Issues Pull Requests Packages Projects Releases Wiki Activity You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long. 1 Commit. 1 Branch. 0 Tags. 140 MiB ... sbm / sbm cacl2 limestone clay re...
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The removal capacity of fluoride was dependent on calcite surface area [27] . Jain and Jayaram (2009) used limestone (LS) and aluminium hydroxide impregnated limestone (AILS) for removal of
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For efficient fluoride removal, it requires more time, about 20 hr, because limestone dissolutes in small amounts at neutral pH. In this work, two common laboratory acids were added to the fluoride water before filtration through the limestone column and it was found that in the presence of acid, the removal capacity of limestone not only ...
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Acid enhanced limestone defluoridation of water has been studied in a crushed limestone column reactor using oxalic acid (OA). The defluoridation has been studied with varying initial fluoride concentrations of 5, 10, 15 and 20 mg/L and acid concentrations of 0.01, 0.05 and 0.1 M.The fluoride removal was found to increase with …
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In order to examine the quantitative relations of fluoride removal ability of the limestone samples with surface area, total pore volume and density, we have plotted the remaining fluoride concentrations after treatment for varying [F] 0 against the BET surface area, total pore volume and density of the limestone samples at fixed [PA] 0 (Fig. 8).
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mixtures where other contaminants can affect the removal process. Batch experiments were used to determine the impact of phosphate (PO 4 3) on the removal of fluoride from solution by calcite. In the experiments, up to 2,000mg/L F and 500mg/L PO 4 3 were used with 150mm and 1.18mm calcite fractions at solid-to-solution
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When HCl-cleaned calcite was used, the observed fluoride removed was similar to that of raw crushed limestone, but constitutes 5.1±1.2% of the available number of adsorption sites. These results compare to a removal of ~0.4% determined by Fan et al. (6) using a calcite size fraction of 212 to 250 µm with a surface area of 0.0057 m2/g …
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Fluoride Removal by Calcite: Evidence for Fluorite Precipitation and Surface Adsorption Error loading file. Explore more content es0505090_si_001.pdf (83.82 …
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Calcite shows a large fluoride removal capacity under extremely high fluoride concentrations, which is common in fluorine-containing industrial wastewater or groundwater of natural fluorine enrichment areas (Turner et al., 2005; Wan et al., 2021). ... Physical treatment of calcite by crushing limestone into much smaller particles was a …
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examines the known role of citrate ion to induce fluoride ion to co-precipitate in calcite, and evaluates its effectiveness to improve the passive, two-column reactor of Reardon …
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Fluoride contamination of groundwater, both anthropogenic and natural, is a major problem worldwide. In this study, fluoride removal by crushed limestone (99% …
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Fluoride contamination of groundwater, both anthropogenic and natural, is a major problem worldwide. In this study, fluoride removal by crushed limestone (99% pure calcite) was investigated by batch studies and surface-sensitive techniques from solutions with fluoride concentra tions from 150 μmol/L (3 mg/L) to 110 mM (∼2100 mg/L).
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Mechanism of fluoride removal by phosphoric acid-enhanced limestone: equilibrium and kinetics of fluoride sorption. Sweety Gogoi, R. K. Dutta. Engineering. 2016. AbstractWith a fourfold increase in the selective fluoride removal capacity of limestone, to 4.38 mg/g, phosphoric acid (PA)-enhanced limestone has been found to be a competent ...
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The results of batch experiments of F-removal with crushed limestone chips of 3-4 mm size, as a function of initial concentrations of CA up to 0.1 M are shown in Fig. 1. It can be seen from the figure that addition of the acid to water before treatment with crushed limestone lowers the F-concentration from its initial
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DOI: 10.1016/j.chemosphere.2022.133729 Corpus ID: 246351820; Mechanisms of fluoride uptake by surface-modified calcite: A 19F solid-state NMR and TEM study. @article{Wang2022MechanismsOF, title={Mechanisms of fluoride uptake by surface-modified calcite: A 19F solid-state NMR and TEM study.}, author={Jingzhao …
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This fluoride removal efficiency was higher than with the limestone reactor of Reardon and Wang (by a further reduction of 1.19 mg/L fluoride in total) yet still lower than the predicted efficiency. One important reason of the lower fluoride removal efficiency than with prediction is that the citrate ions suppressed the precipitation of calcite.
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When HCl-cleaned calcite was used, the observed fluoride removed was similar to that of raw crushed limestone, but constitutes 5.1±1.2% of the available …
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With consistent removal of fluoride from any initial concentration to a desired concentration, a recurring cost of only Rs 0.005/l of water and an estimated life of the limestone bed of about 50 ...
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Fluoride contamination of groundwater, both anthropogenic and natural, is a major problem worldwide. In this study, fluoride removal by crushed limestone (99% …
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Fluoride removal quantitatively related with surface area, porosity and density of limestone. • Fe 2 O 3 and Al 2 O 3 impurities make the pH of treated water …
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Softening pellets are spherical crystal beads of calcite nature and a waste product of hardness removal in pellet crystallization reactors [Citation 35]. Other calcium carbonate rich materials such as calcite particles, limestone and eggshell have been observed to have affinity for F - sorption [ Citation 36–38 ], making softening pellets an ...
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An examination of defluoridation by industrial grade limestone indicated that a combination of precipitation and adsorption of fluoride can be more effective for defluoridation of water. Pre-acidified fluoride water using two edible acids, viz., acetic acid (AA) and citric acid (CA) have been used for treatment by crushed limestone of …
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This fluoride removal efficiency was higher than with the limestone reactor of Reardon and Wang (by a further reduction of 1.19 mg/L fluoride in total) yet still lower than the predicted efficiency. One important reason of the lower fluoride removal efficiency than with prediction is that the citrate ions suppressed the precipitation of calcite.
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Oyster shells are a rich source of calcium carbonate 10 – 12 that can be used for fluoride removal 13. Calcium carbonate can be used to produce hydroxyapatite which has been shown to be effective for fluoride removal from water 14. Phosphoric acid–enhanced limestone has improved fluoride removal efficiency and is a low-cost material 15. In ...
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DOI: 10.1016/J.COLSURFA.2014.03.040 Corpus ID: 96067880; Effects of fluoride and polymeric additives on the dissolution of calcite and the subsequent formation of fluorite @article{Yang2014EffectsOF, title={Effects of fluoride and polymeric additives on the dissolution of calcite and the subsequent formation of fluorite}, author={Taewook Yang …
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