In this PA-enhanced limestone defluoridation (PAELD) technique, fluoride is removed from 0.526 mM to 0.50–52.60 μM in 3 h with near neutral final pH. The presence of …
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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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The influence of coexisting anions on fluoride removal was low for all limestone samples and followed the order sulfate > chloride > nitrate. The surface area and total pore volume above 2.55 m² ...
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Local limestone has fluoride removal abilities by phosphoric acid (PA)- local crushed Limestone treatment (PACLT), with the treated water conforming to WHO guidelines for Fluoride in drinking ...
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The potential application of lime-sludge waste (LSW) from paper mills in removal of excess fluoride from water has been studied. Strings of batch experiments were carried out to assess the fluoride removal ability of dried micrometer-sized LSW in presence of phosphoric acid (PA) by varying operational parameters, viz., initial fluoride concentration, initial PA concentrations, …
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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 diameter 3-4 mm to precipitate fluoride …
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Indian Journal of Chemical Technology Vol.17, March 2010, pp. 120-125 Fluoride removal from water using crushed limestone Suresh K Nath & Robin K Dutta* Department of Chemical Sciences, Tezpur University, Napaam, Tezpur 784 028, India Email: [email protected], [email protected] Received 15 April 2009; revised 22 January 2010 An examination of defluoridation …
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Download Table | -Chemical composition of limestone from publication: Fluoride removal from water using crushed limestone | An examination of defluoridation by industrial grade limestone indicated ...
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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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limestone lowers the F-concentration from its initial value of 10 mg/L to below 2 mg/L, which is much better compared to the fluoride removal by limestone filtration alone 14. The ability of the crushed limestone chips to remove F-increased with increasing the acid concentration. However, the removal became poorer
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For limestone, fluoride removal reaches 65% and fluoride decreases from 4 mg/L to 1.4 mg/L with 0.65 g/L rock (Labastida et al., 2017). Compared with the fluoride removal ability and cost of these calcium-containing materials (Table 1), FGD gypsum performs attractively as an industrial by-product and may be regarded as a cost-effective material ...
WhatsApp: +86 18221755073In this study, fluoride removal by crushed limestone (99% pure calcite) was investigated by batch studies and surface-sensitive techniques from solutions with fluoride …
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The presence of PA increases the fluoride removal capacity of limestone to 1.10 mg/g compared to 0.39 mg/g reported in its absence. The changes in fluoride removal with variation in initial PA concentration, initial fluoride concentration and the final pH have been found to be statistically significant with p < 0.05.
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A two-column limestone reactor has been designed to reduce fluoride concentrations from wastewaters to below the maximum contaminant level (MCL limit) of 4 …
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An efficient and simple defluoridation method has been evaluated using locally available limestone and some acidic chemicals. For efficient fluoride removal, it requires more time, …
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] have already been used for fluoride removal (Nath and Dutta 2013). Treatment of fluoride water by limestone has been proven to be a good method for fluoride removal. It takes about 20 hrs of residential time to remove fluoride without adding any acid to the water (Reardon and Wang 2000). After addition of the acid, the time was reduced to
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The concentrations of the anions were varied in the range of 100–500 mg/L. Results have shown that the fluoride removal by these limestone – samples decreased in the order NO3 < Cl < SO24, with the increase in their concentration, with similar trend for all six samples [30]. There is a − low impact of NO− 3 on fluoride removal because ...
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With 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 adsorbent mate-rial for fluoride removal. The PA-enhanced limestone has been characterized and its fluoride sorption has been studied using various models.
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The limestone specimen designated for the fabrication of the ballasted material was procured from a coal mining operation situated in the Western region of China. The chemical constitution of the limestone was scrutinized employing an X-ray fluorescence (XRF) spectrometer (ARL, Thermo Scientific, USA). ... The fluoride removal in the ballasted ...
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Recently, we reported a fluoride removal technique in which fluoride containing water is acidified with phosphoric acid (PA) and allowed to react with crushed limestone bed which removes fluoride from initial 10 mg L −1 to as low as 0.1 mg L −1 [31]. The required concentration of PA to remove fluoride is also very low compared to that of other edible acids …
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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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However, a fluoride removal method which is low-cost, safe, environment-friendly and can be used by a layman without requiring power is still not available. recently reWe ported a fluoride removal technique based on phosphoric acid-crushed limestone treatment (PACLT), which meets most of the above-mentioned requirements (Gogoi, 2015).
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Ezzeddine et al. [13] investigated the fluoride removal from aluminum fluoride manufacturing wastewater precipitation-neutralization using lime or limestone. The effects of experimental conditions such as lime or limestone dosage, initial fluoride concentration and initial pH on fluoride removal efficiency and final pH were evaluated.
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Fluoride removal from groundwater has been studied by addition of dilute phosphoric acid (PA) to the influent water before limestone treatment through laboratory plug-flow column experiments and bench-scale plug-flow pilot tests. In this PA-enhanced limestone defluoridation (PAELD) technique, fluoride is removed from 0.526 mM to 0.50–52.60 μM in 3 h …
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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 …
WhatsApp: +86 18221755073Hydroxyapatite derived from limestone or oyster shells has the potential for significant fluoride removal from water. Hydroxyapatite that was produced by reaction between oyster shells and (NH 4 ...
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treatment with crushed limestone, where fluoride was removed by both precipitation of fluorite and adsorption of fluoride on limestone surface21,33–37. However, fluoride removal by these methods is associated with one or more shortcomings, such as high operational and maintenance costs, low capacity of adsorbent, frequent replacement of
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Fluoride removal from water using crushed limestone Indian Journal of Chemical Technology Vol.17, March 2010, pp. 120-125 Fluoride removal from water using crushed limestone Suresh K Nath & Robin K Dutta* Department of Chemical Sciences, Tezpur University, Napaam, Tezpur 784 028, India Email: [email protected], [email protected]
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Using limestone for fluoride removal not only addresses water quality issues but also reduces the environmental impact associated with chemical treatments. Limestone samples with a surface area greater than 2.55 m 2 /g, a total pore volume above 0.0094 cm³/g, and a density below 2.68 g/cm³ effectively reduce the fluoride concentration from 10 ...
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inexpensive technology to reduce fluoride concentrations in waters to recommended drinking water limits is of significant benefit to communities affected by fluorosis world-wide. Three …
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