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  • Fluoride removal from groundwater by limestone treatment ...

    Apr 01, 2015  The cost of limestone is US$ ≈27 per metric ton. Taking the fluoride removal capacity of limestone as 1.01 mg/g, the cost of limestone for fluoride removal from 0.526 mM to below 0.052 mM at 10 mM PA, has been estimated as US$ ≈0.00021/L of treated water.

  • Cited by: 29
  • (PDF) Fluoride removal from water using crushed limestone

    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 ...

  • Community level defluoridation of groundwater with ...

    Jul 01, 2019  Since these soluble additives were producing an insoluble product in the form of different calcium phosphates, the presence of insoluble CaCO 3 was necessary to trap them for further use as fluoride adsorbents. The efficacy of F removal by limestone chips modified with different amounts of CaCl 2 and NaH 2 PO 4 was studied.

  • Author: J. Vijayeeswarri, M. Geethapriyai, V. Ramamurthy
  • Fluoride Removal Crushed Limestone Calcite Wiki

    Fluoride Removal Crushed Limestone Calcite Wiki. Nov 10 2005 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 surfacesensitive techniques from solutions with fluoride concentra tions from 150 moll 3 mgl to 110 mm 2100 mgl.

  • A Limestone Reactor for Fluoride Removal from Wastewaters ...

    Jun 30, 2000  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 precipitate the calcite dissolved in the first ...

  • Cited by: 415
  • Fluoride removal from water by adsorption—A review ...

    Adsorbent dose of 4 g/L was found to be optimum for fluoride removal. Fluoride removal efficiency was found to be independent of pH over a wide range of 3–9. The fluoride removal efficiency decreased by 24% and 34% in presence of PO 4 3− and CO 3 2− ions respectively, and also decreased by 56% in presence of HCO 3 − ions. Synthesized ...

  • Fluoride removal from water using crushed limestone

    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

  • Investigating the Efficacy of Saw Dust in Fluoride Removal ...

    Jun 21, 2019  The maximum removal of fluoride was found to be 88% at optimum conditions (pH 7, adsorbent dose 0.20 g/L and initial fluoride concentration 5 mg/L). Among the various kinetic models used, pseudo-second-order model best fitted the kinetic data and Langmuir isotherm was also best fitted. The maximum capacity of adsorption was found to be 16.5 mg/g.

  • 22 Technologies for fluoride removal Leela Lyengar

    Te c hnologies for fluoride removal 22.1. Introduction Fluoride is a normal constituent of natural water samples. Its concentration, though, varies significantly depending on the water source. Although both geological and man-made sources contribute to the occurrence of fluoride in water, the major contribution comes from geological resources.

  • Fluoride ions vs removal technologies: A study - ScienceDirect

    Nov 01, 2016  The fluoride removal of DEW with 0.025% MnO 2 was effective at a pH of 7.15. The regeneration of the spent sorbent was found to be efficient by washing it with 1.5 M NaOH which reveals the reversibility of the reaction used during the fluoride removal (Sivasankar et al., 2011, Mohapatra et al., 2004) . 4.2.2. Bauxite

  • Modified Crushed Oyster Shells for Fluoride Removal from Water

    Oyster shells are a rich source of calcium carbonate 10,11,12 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 ...

  • Fluoride Removal Crushed Limestone Calcite Wiki

    Fluoride Removal Crushed Limestone Calcite Wiki. Nov 10 2005 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 surfacesensitive techniques from solutions with fluoride concentra tions from 150 moll 3 mgl to 110 mm 2100 mgl.

  • A Limestone Reactor for Fluoride Removal from Wastewaters ...

    Jun 30, 2000  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 precipitate the calcite dissolved in the first ...

  • Fluoride Removal from Contaminated Water by Limestone ...

    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.

  • A Limestone Reactor for Fluoride Removal from Wastewaters

    Batch study of fluoride removal using CHN reveals that with an initial fluoride concentration of 50–250 mg/L and fixed CHN dose of 0.12 g/L, fluoride removal was found to be 450 ± 10 mg/g of ...

  • Fluoride removal from groundwater by limestone treatment ...

    The fluoride ion-selective electrode was used to determine the fluoride removal efficiency. 98.8% of fluoride was removed at pH 3.0, but at pH ~7.0, 85% of fluoride was removed; it shows that the ...

  • Modified Crushed Oyster Shells for Fluoride Removal from ...

    Apr 01, 2020  Phosphoric acid–enhanced limestone has improved fluoride removal efficiency and is a low-cost material 15. In composition, oyster shells resemble limestone

  • Limestone as a sustainable remediation option for water ...

    Limestones from various geologic formations removed up to 65% fluoride from water. • Removal efficiency was independent of particle size (from 63 to 1410 μm) and CaCO 3.. F − concentration profiles suggest external sphere complex formation.. CaF 2 formation in the solution bulk besides calcite surface was shown by SEM-WDS.

  • A critical study on efficiency of different materials for ...

    Mar 13, 2013  Fluoride is a persistent and non-biodegradable pollutant that accumulates in soil, plants, wildlife and in human beings. Therefore, knowledge of its removal, using best technique with optimum efficiency is needed. The present survey highlights on efficacy of different materials for the removal of fluoride from water. The most important results of extensive studies on various key factors (pH ...

  • Removal of Fluorine from Water by the Aluminum-Modified ...

    to remove the fluorine in the drinking water. The factors of influencing the fluorine removal rate, including the types of the alumium salt, the initial fluorine ion concentration, the mass of the adsorbent and the adsorption time, was studied in the re-search. The fluorine removal percentage was 97% by 10 g/L

  • (PDF) Community Level Defluoridation of Groundwater with ...

    Effectiveness of fluoride removal by adsorbent prepared by modifying limestone chips (500 g) with different amounts (g) of calcium chloride and monosodium phosphate on repeated exposure of 5 g ...

  • Design Manual: Removal of Fluoride from Drinking Water ...

    ----- EPA/600/R-14/236 March 2014 Design Manual Removal of Fluoride from Drinking Water Supplies by Activated Alumina Prepared by ALSA Tech, LLC North Bethesda, MD 20852 and Battelle Columbus, OH 43281-2693 Under EPA Contract No. EP-C-11-038 for Thomas J. Sorg Task Order Manager Water Supply and Water Resources Division National Risk Management Research Laboratory Office of

  • Fluoride removal performance of phosphoric acid treated ...

    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 fluoride concentration, flow rate and amount of adsorbent mass.

  • Removal of Fluoride from Drinking Water Using Modified ...

    The study describes the removal of fluoride from drinking water using modified immobilized activated alumina (MIAA) prepared by sol-gel method. The modification was done by adding a specific amount of alum during the sol formation step. The fluoride removal efficiency of MIAA was 1.35 times higher as compared to normal immobilized activated alumina.

  • Modified Crushed Oyster Shells for Fluoride Removal from ...

    Apr 01, 2020  Phosphoric acid–enhanced limestone has improved fluoride removal efficiency and is a low-cost material 15. In composition, oyster shells resemble limestone

  • A Limestone Reactor for Fluoride Removal from Wastewaters

    Batch study of fluoride removal using CHN reveals that with an initial fluoride concentration of 50–250 mg/L and fixed CHN dose of 0.12 g/L, fluoride removal was found to be 450 ± 10 mg/g of ...

  • A Limestone Reactor for Fluoride Removal from Wastewaters ...

    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 precipitate the calcite dissolved in the first ...

  • (PDF) Community Level Defluoridation of Groundwater with ...

    Effectiveness of fluoride removal by adsorbent prepared by modifying limestone chips (500 g) with different amounts (g) of calcium chloride and monosodium phosphate on repeated exposure of 5 g ...

  • Fluoride Removal from Contaminated Water by Limestone ...

    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.

  • Fluoride removal performance of phosphoric acid treated ...

    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 fluoride concentration, flow rate and amount of adsorbent mass.

  • A critical study on efficiency of different materials for ...

    Mar 13, 2013  Fluoride is a persistent and non-biodegradable pollutant that accumulates in soil, plants, wildlife and in human beings. Therefore, knowledge of its removal, using best technique with optimum efficiency is needed. The present survey highlights on efficacy of different materials for the removal of fluoride from water. The most important results of extensive studies on various key factors (pH ...

  • Assessing the Effectiveness of Limestone from Oterkpolu ...

    The application of the developed methodology (Column Adsorption Analysis) yielded 80% and 67% fluoride removal from two groundwater water samples (BNN8 and BNB6) respectively from the Bongo district of the Upper East region of Ghana. Thus, the fluoride levels in the 330 mL samples were reduced from 7.5 and 6.2 mg/L to 1.5 and 2.0 respectively.

  • Removal of Fluoride from Drinking Water Using Modified ...

    The study describes the removal of fluoride from drinking water using modified immobilized activated alumina (MIAA) prepared by sol-gel method. The modification was done by adding a specific amount of alum during the sol formation step. The fluoride removal efficiency of MIAA was 1.35 times higher as compared to normal immobilized activated alumina.

  • Fluoride Removal from Aluminium Finishing Wastewater by ...

    Feb 18, 2015  Fluoride Removal by Adsorption. After the precipitation step with Ca(OH) 2 and the removal of significant amount of fluoride (88.36 %), the treated wastewater required polishing in order to meet the discharge limits (8 mg/L). In this study, adsorption onto hydroxyapatite was used as post-treatment and equilibrium studies were carried out to determine maximum fluoride removal conditions.

  • Nilogon for fluoride removal from groundwater

    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.

  • RESEARCH ARTICLES Field experience of Fluoride Nilogon: a ...

    phoric acid was treated in a crushed limestone bed (1–20 mm) for 3 h and filtered through a sand–gravel filter to retain a desired 0.7 mg/l [F–] with pH of 7.44– 7.9 and relevant water quality parameters meeting WHO guidelines. A slightly higher dose can totally remove fluoride. The fluoride removal

  • Extrinsic stain removal efficacy of a new dentifrice ...

    1. Am J Dent. 2011 Jul;24 Spec No A:28A-31A. Extrinsic stain removal efficacy of a new dentifrice containing 0.3% triclosan, 2.0% PVM/MA copolymer, 0.243% NaF and specially-designed silica for sensitivity relief and whitening benefits as compared to a dentifrice containing 0.3% triclosan, 2% PVM/MA copolymer, 0.243% NaF and to a negative control dentifrice containing 0.243% NaF: a 6

  • Treatment of Ammonium Fluoride Solutions in a ...

    The observed good fluoride removal has been attributed to a combination of two mechanisms of fluoride removal, viz., precipitation of calcium fluoride and adsorption of fluoride ions on limestone ...

  • Modified Crushed Oyster Shells for Fluoride Removal from ...

    Apr 01, 2020  Phosphoric acid–enhanced limestone has improved fluoride removal efficiency and is a low-cost material 15. In composition, oyster shells resemble limestone

  • A Limestone Reactor for Fluoride Removal from Wastewaters ...

    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 precipitate the calcite dissolved in the first ...

  • Nilogon for fluoride removal from groundwater

    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.

  • Fluoride Removal from Contaminated Water by Limestone ...

    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.

  • Two-week extrinsic stain removal efficacy of a sodium ...

    Two-week extrinsic stain removal efficacy of a sodium fluoride dentifrice with high cleaning silica: results from two randomized, controlled clinical trials. Ni L(1), Li J, He T, Chang J, Sun L. Author information: (1)Department of Operative Dentistry and Nursing, School of Stomatology, Fourth Military Medical University, Xian, China.

  • RESEARCH ARTICLES Field experience of Fluoride Nilogon: a ...

    phoric acid was treated in a crushed limestone bed (1–20 mm) for 3 h and filtered through a sand–gravel filter to retain a desired 0.7 mg/l [F–] with pH of 7.44– 7.9 and relevant water quality parameters meeting WHO guidelines. A slightly higher dose can totally remove fluoride. The fluoride removal

  • Fluoride Removal Crushed Limestone Calcite Wiki Texas

    fluoride removal crushed limestone calcite wiki mobiletel. 24 Effect of contact time on the removal of fluoride from natural groundwater Limestone or calcite, which is abundant in the severely fluorideaffected areas of dental fluorosis source wikidentalfluorosis About 10, 50 and 100 grams aliquots of the raw crushed limestone

  • Extrinsic stain removal efficacy of a stannous fluoride ...

    A nine-week, randomized and controlled clinical trial was conducted to compare the stain removal efficacy of a 0.243% sodium fluoride dentifrice containing 7% sodium hexametaphosphate (5% ...

  • Removal of Fluoride from Drinking Water Using Modified ...

    The study describes the removal of fluoride from drinking water using modified immobilized activated alumina (MIAA) prepared by sol-gel method. The modification was done by adding a specific amount of alum during the sol formation step. The fluoride removal efficiency of MIAA was 1.35 times higher as compared to normal immobilized activated alumina.

  • How to Remove Fluoride from Drinking Water

    Recently limestone and heat-treated soil were tried for fluoride removal. Limestone was used in a two-column continuous flow system (limestone reactor) to reduce fluoride concentrations from wastewaters to below the MCL (Maximum contaminant level) of 4 mg/L. Calcite was forced to dissolve and fluorite to precipitate in the first column.

  • Removal of Fluoride Ions from Wastewater Using Green and ...

    obtained. The fluoride removal was calculated by using the following equation: Fluoride removal= @ A Where, C o and C e are the initial and equilibrium fluoride concentrations in water (mg/l), respectively. 2.2.2. Continuous system experiments A fluidized bed reactor which is shown in

  • Lime in Flue-gas Treatment Graymont

    Lime and limestone are used in the treatment of pollutants such as sulfur dioxide (SO 2), hydrogen chloride (HCl), hydrogen fluoride (HF), sulfur trioxide (SO 3), Asenic (As), Selenium (Se), fine particulates and mercury (Hg).. Lime and limestone products are used in both wet and dry flue-gas desulfurization (FGD) processes.

  • Drinking Water Treatability Database

    Because of the high effectiveness of the BATs, treatment would not be a limiting factor if a lower MCL was set [2009]. Other treatment technologies available for fluoride removal include: ion exchange, lime softening, electrodialysis, and adsorption with various types of media including activated carbon, bone chars and clays [1895][1957][1958].

  • Bentonite and montmorillonite nanoparticles effectiveness ...

    Application of many adsorbents for fluoride removal from aqueous solution was investigated. In a study performed by Bazrafshan et al., efficiency of ZnCl 2 treated Eucalyptus leaf as a natural adsorbent for removal of fluoride from water environment was evaluated. In another research, Daifullah and colleagues studied the application of KMnO 4-modified activated carbon derived from steam ...