A 32% fluoride removal observed with the fresh limestone powder was found to increase to 93% with M9. The fluoride removal increased considerably on changing the adsorbents in the order: L0 < M3 < M6 < M9 as expected ( Fig. 3 A).
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Fatcatnewsvideo - Video - calcium based adsorbents fluoride ... Date: 10/9/2012: Title: calcium based adsorbents fluoride removal crushed limestone calcite wiki: Description: calcium based adsorbents fluoride removal crushed ...
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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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A two-column limestone reactor has been designed to reduce fluoride concentrations from wastewaters to below the maximum contaminant level (MCL limit) of 4 mg/L. The reactor functions by forcing calcite (CaCO3) to dissolve and fluorite (CaF2) to precipitate in the first column. The second column is not necessary to remove fluoride but is used to …
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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 as CaF 2 in addition to adsorption of fluoride on limestone. The study has been ...
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Numerous groundwater wells in Mexico exceed the maximum allowable fluoride (F−) and arsenic (As) drinking water concentration requirements, posing an environmental and health risk to the population that relies solely on these wells for drinking water sources. Since encouraging results have been obtained utilizing native limestones to remove some toxic …
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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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Fluoride removal was achieved from initial 10 mg/L to less than 1 mg/L in 30 min. The initially rapid fluoride removal slowed down gradually to reach equilibrium in about 30 min as expected. Such dependence of fluoride removal on initial [F–]0 and contact time was reported for other adsorbents [36,41,47].
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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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fluoride concentration from up to 150 mg/L to below the maximum contaminant level (4 mg/L) at the residence time of 4 h. When the residence time was 24 h, fluoride concentration was reduced to below the drinking water standard (1.5 mg/L). This fluoride removal efficiency was higher than with the limestone reactor of Reardon and Wang (by a further
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The method can remove fluoride from a high initial concentration to zero ppm. However, as a small quantity of fluoride is required for healthy teeth and bones, the final concentration of fluoride is kept at 0.65 (±0.1) ppm with this dose of phosphoric acid. The crushed limestone bed remains active for at least four years and nine months.
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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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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 as …
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adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A
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Download Citation | On Sep 1, 2024, Xiaohang Zhang and others published Development of a limestone-based ballasted material for enhanced co-removal of turbidity and fluoride from coal mine water ...
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This document discusses a study on using crushed limestone to remove fluoride from water. The researchers examined using acetic acid and citric acid to pre-treat the fluoride water before treatment with crushed limestone. This was found to significantly improve fluoride removal by increasing the calcium ion concentration through dissolution of calcite in the limestone. Batch …
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From the result, a related trend was viewed for contact time and sorption efficiency of activated kaolin and limestone. The rate of fluoride removal by activated kaolin was increased from 2.15-3.82 mg F − /g and by limestone was increased from 1.65-3.25 mg F −1 /g during 10-60 min. However, there was no substantial increase in the removal ...
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Fluoride removal by hydrothermally modified limestone powder using phosphoric acid ... Fluoride removal by hydrothermally modified limestone powder using phosphoric acid. Robin Dutta. 2016, Journal of Environmental Chemical Engineering. See Full PDF Download PDF.
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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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A study of suitability of limestone for fluoride removal by phosphoric acid-crushed limestone treatment. Rajkamal Mohan R. K. Dutta. Environmental Science. 2020; 9. Save. Precipitation and adsorption during fluoride removal from water by …
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This study introduces the use of a waste by-product from wet limestone flue gas desulfurization as a potential material for fluoride removal. Systematic laboratory-scale …
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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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Free-drift batch reactor experiments using calcite (limestone, CaCO 3) were used to study fluoride removal through precipitation as fluorite (CaF 2) from solutions with concentrations reflective of an industrially contaminated site.The influence of CO 2 partial pressure (pCO 2), stirring rate, and fluoride concentration were investigated in this paper.. …
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The chemical reaction in the process of fluoride removal with limestone-gypsum from flue gas was described. Based on the two-film theory, the kinetic model of CaCO3-HF reaction was established and ...
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Gogoi, S.; Dutta, R.K. 2016: Mechanism of fluoride removal by phosphoric acid-enhanced limestone: equilibrium and kinetics of fluoride sorption Desalination and Water Treatment 57(15): 6838-6851 Rodriguez, M.G.; Martinez, S.A.D. 2005: Removal of Cr(VI) from wastewaters in a tubular electrochemical reactor Journal of Environmental Science and ...
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Fluoride removal from water using crushed limestone 2 calcium chloride CaCl 2 and calcium sulphate CaSO 4 have already been tried for fluoride removal 33. Calcium chloride and … اقرأ أكثر
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Fluoride in drinking water above permissible levels is responsible for dental and skeletal fluorosis. In this study, removal of fluoride ions from water using phosphoric acid treated lime was investigated in continuous and point-of-use system opera tions. In the continuous column operations, fluoride removal performance was investigated as a function of the …
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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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Simple scrubbing and rinsing is a preferable method for regeneration of limestone as it is almost equally effective with lime or NaOH. Sorption of fluoride by calcium phosphates …
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