AbstractThe purpose of this study is to apply a hybrid process that combines the precipitation with hydrate lime along with reverse osmosis (RO) treatment to deal with a real industrial wastewater having an excessive fluoride concentration of 3,200 mg/L. The effluent is discharged from an aluminum fluoride manufacturing unit. Neutralization with …
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In precipitation, fluoride-rich water is treated with aluminum salts and lime, which is then taken through filtration or sedimentation. Lime reacts with the free fluorides, originating from salts such as NaF and HF (acids released by industries), forming calcium fluoride (CaF 2), an insoluble impurity that can be eliminated.Since aluminum acts as a …
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1. Introduction. Fluoride is a difficult-to-remove major groundwater contaminant of worldwide concern (Shannon et al., 2008).Though a small concentration …
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The FTIR spectra of fresh limestone powder (L0) and the modified limestone powder samples, prepared in the presence of PA concentrations of 0.30 M (M3), 0.60 M (M6) and 0.90 M (M9), are shown in Fig. 1.The major characteristic peaks for calcium carbonate were observed around 2375, 1417, 878 and 710 cm −1 in fresh …
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The safe limit of fluoride in drinking water is 1.0 mg/L [19].The endemic fluorosis in India is largely of hydrogeochemical origin. It has been observed that low calcium and high bicarbonate alkalinity favor high fluoride content in groundwater [20], [21].Water with high fluoride content is generally soft, has high pH and contains large …
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DOI: 10.1016/j.jenvman.2015.01.031 Corpus ID: 39182341; Fluoride removal from groundwater by limestone treatment in presence of phosphoric acid. @article{Gogoi2015FluorideRF, title={Fluoride removal from groundwater by limestone treatment in presence of phosphoric acid.}, author={Sweety Gogoi and Suresh Kumar …
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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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The removal of fluoride using limestone was most effective at a pH of 7.22, with a sorption capacity of 2.57 mg/g. It took 90 min to reach equilibrium. Groundwater samples were also used in the sorption investigation; the study revealed that limestone powder could decrease fluoride from 3.48 to 0.878 ppm. SEM and FTIR spectroscopy …
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The PA-enhanced limestone has been characterized and its fluoride sorption has been studied using various models. The removal of fluoride in the process has …
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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 adsorbent material 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 rocks identified as KIT1 and KSS showed an increasing removal trend alongside decreasing particle size; the highest removal (~ 65%) was obtained with KIT1 from a solution that contained 4 mg/L fluoride and the smallest particle size (63–125 μm), while KSS only reached 22% removal under the same conditions.A final concentration …
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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 …
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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 fluoride concentrations from 150 ...
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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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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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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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A better understanding of currently available processes is necessary to develop economical, efficient, and effective methods for fluoride removal. Fluoride can either be coated, adsorbed using a wide range of both …
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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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This review comprehensively explores fluoride removal from phosphogypsum, focusing on its composition, fluorine-containing compounds, characterization methods, and defluorination techniques. It initially outlines the elemental composition of phosphogypsum prevalent in major production regions and infers the …
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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 material 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 result obtained was 80.6% of fluoride removal at optimized parameters for an initial fluoride concentration of 50 mg/L. Langmuir isotherm was the best fit for fluoride removal with 16.67 mg/g of adsorption capacity (Srimurali and Karthikeyan, 2008). Jain and Jayaram examined hydroxide impregnated limestone (A1LS) for fluoride …
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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. …
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Removal of fluoride from spent potliner contaminated groundwater using reactive geomaterials Creator Abu Zaher, Hana Relation University of Newcastle Research …
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Fluoride concentration in drinking water has become a global challenge due to its effects on the human body. While small level (1–1.5 mg·L⁻¹) strengthens enamel and bone formation, higher ...
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A better understanding of currently available processes is necessary to develop economical, efficient, and effective methods for fluoride removal. Fluoride can either be coated, adsorbed using a wide range of both mineral and organic constituents or can be directly rejected by membrane processes, such as reverse osmosis and …
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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.. Equilibrium …
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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 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. The estimated recurring ...
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The removal of fluoride using limestone was most effective at a pH of 7.22, with a sorption capacity of 2.57 mg/g. It took 90 min to reach equilibrium. Groundwater …
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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 …
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