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 …

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 ...

DOI: 10.1016/j.jece.2020.104410 Corpus ID: 225298804; A study of suitability of limestone for fluoride removal by phosphoric acid-crushed limestone treatment @article{Mohan2020ASO, title={A study of suitability of limestone for fluoride removal by phosphoric acid-crushed limestone treatment}, author={Rajkamal Mohan and Robin K. …

A study of suitability of limestone for fluoride removal by phosphoric acid-crushed limestone treatment. ... The reactors were filled with crushed limestone. Groundwater was then spiked with 3, 5, 10, 15, 20 mg/L of fluoride by adding NaF and calculated volumes of 85 % W/V PA. ... Fluoride removal by calcite: evidence for …

Results and discussion Characteristics of calcite treatment process. In a conventional F − removal process, Ca 2+ ions are added into the wastewater to create CaF 2 precipitate and the remaining F − concentration is mainly determined by the remaining Ca 2+ concentration according to the solubility product of fluorite as shown in equation …

Fatcatnewsvideo.com - 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 ...

A study of suitability of limestone for fluoride removal by phosphoric acid-crushed limestone treatment. ... (PA)-crushed limestone treatment (PACLT). The effects of varying initial fluoride [F] ... The fluorapatite-coated calcite (FCC) with a coating time of 6 h and an FAP coverage of the calcite surface of 82–86 % was selected as the …

Calcium based adsorbents fluoride removal crushed limestone calcite. 2019917brick making. four main ingredients are required for brick making suitable clay and sand, water, fuel and manpower. the clay must be easily availe, be plastic when mixed with small amounts of water, develop strength upon drying and develop hard and durable …

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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 aluminium to the water and adjustment of the pH of water is necessary. Similarly, the method developed at the IISc, India also uses alkaline

Low cost materials such as limestone, quick lime, bentonite, kaolinite, china clay and calcite have been tested for fluoride removal and proven to be effective 7.

Fluoride Removal by Calcite: Evidence for Fluorite Precipitation and …

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 …

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 carried out in batches by varying the acid concentration and contact time.

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 ...

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 ...

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 ...

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.

AbstractFree-drift batch reactor experiments using calcite (limestone, CaCO3) were used to study fluoride removal through precipitation as fluorite (CaF2) from solutions with concentrations reflective of an industrially contaminated site. The influence of CO2 partial pressure (pCO2), stirring rate, and fluoride concentration were investigated …

Pre-acidified water containing 0.68 mM phosphoric 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 ...

Several interesting studies were conducted subsequently by adding other acids to the influent water, before treatment with crushed limestone, where fluoride was removed by both precipitation of ...

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).

Fluoride removal from water using crushed limestone. Indian Journal of Chemical Technology, 17, 120-125. Nath, S.K. and Dutta, R.K. 2012. Acid-enhanced limestone defluoridation in column reactor using oxalic acid. ... Binning, P. and Stipp, S.L.S. 2005. Fluoride removal by calcite: evidence for fluoride precipitation and surface adsorption ...

The FT-IR sorbent spectrum prepared from Corbula trigona shell waste before and after fluoride ion treatment are shown in Fig. 2. The main characteristic peaks observed at 840, 1382 and 1685 cm ...

To investigate the influence of FAP/calcite mass ratio on the removal of fluoride, seed crystal with a mass ratio (FAP (g) + calcite (g)) of 0 + 10, 2 + 8, 4 + 6, 6 + 4, 8 + 2, or 10 + 0 was added to different polymethyl methacrylate beakers containing a 1 L fluoride solution with an initial concentration of 9.5 mg/L (0.5 mM).

Calcite can remove fluoride by both sorption and precipitation processes. ... and allowed to react with crushed limestone bed which removes fluoride from initial 10 mg L À1 to as low as 0.1 mg L ...

DOI: 10.1039/d2ew00826b Corpus ID: 258466756; Fluoride removal by calcite and hydroxyapatite @article{JoeWong2023FluorideRB, title={Fluoride removal by calcite and hydroxyapatite}, author={Claresta Joe-Wong and Andrea Alem{'a}n-Reyes and Nam Q. Le and K. Michael Salerno and James K. Johnson and Zhiyong Xia and Danielle R. …

Calcite-(limestone, CaCO 3) based adsorbents have been investigated for F− removal in recent years [[15], [16], [17]] since it is one of the cheap and most viable methods for removing high fluoride concentrations from wastewaters.Calcite nanoparticles (NPs) have indeed been effectively used for the physisorption of fluoride ions from …

Abstract. This manuscript reports on batch and column water-treatment …

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.