scholarly journals A Review of Fluoride Removal from Groundwater

2018 ◽  
Author(s):  
Margandan Karunanithi ◽  
Rachna Agarwal ◽  
Kushal Qanungo
Keyword(s):  
Ion Exchange ◽  
Reverse Osmosis ◽  
Indian Subcontinent ◽  
Fluoride Removal ◽  
Activated Alumina ◽  
High Concentration ◽  
Advantages And Disadvantages ◽  
Bone Charcoal ◽  
Actual Use ◽  
Arid And Semiarid

Most of the arid and semiarid zones of the Indian subcontinent are seriously affected by the fluorosis problem due to high concentration of the fluoride in ground water. Due to leaching of fluoride from the fluoride bearing rocks, the groundwater gets contaminated with fluoride. The different techniques for fluoride removal namely, the Activated alumina, the Nalgonda technique, bone charcoal, contact precipitation, electro-dialysis, reverse osmosis, ion-exchange, clay column, bio-adsorbents and MgO are discussed in detail. Their advantages and disadvantages together with the applicability in actual use also been discussed in the paper.

Innovative concepts of regeneration of decolorization ion exchange resins in sugar refineries

2016 ◽  
pp. 377-380
Author(s):  
Marc André Théoleyre ◽  
Anne Gonin ◽  
Dominique Paillat
Keyword(s):  
Ion Exchange ◽  
Reverse Osmosis ◽  
Energy Supply ◽  
Ion Exchange Resins ◽  
Salt Solutions ◽  
Nanofiltration Membranes ◽  
Local Conditions ◽  
Salt Consumption ◽  
Multiple Effect ◽  
Exchange Resins

Regeneration of resins used for decolorization of sugar solutions is done with concentrated salt solutions. Nanofiltration membranes have been proven effective, in terms of industrial efficiency in decreasing salt consumption. More than 90% of the salt that is necessary for regeneration can be recycled through a combination of direct recycling of intermediate eluates, the separation of colored compounds by use of very selective nanofiltration membranes and a system to concentrate salty permeates. According to specific local conditions on energy supply and cost, the concentration of salty permeates can be either a multiple effect evaporator or a combination of electrodialysis and reverse osmosis. The desalted color compound solution is sent to the molasses, limiting considerably the effluent to be treated. Starting from a liquor of 800 IU, the water requirement is limited to less than 100 L/t of sugar and the amount of wastewater can be reduced to less than 40 L/t of sugar.

Combining reverse osmosis and ion-exchange allows beet distillery condensates to be recycled as fermentable dilution water

Desalination ◽  
2015 ◽  
Vol 363 ◽  
pp. 75-81 ◽  
Author(s):  
Marie-Laure Lameloise ◽  
Marjorie Gavach ◽  
Marielle Bouix ◽  
Claire Fargues
Keyword(s):  
Ion Exchange ◽  
Reverse Osmosis ◽  
Dilution Water

scholarly journals Pyromorphite formation from montmorillonite adsorbed lead

Mineralogia ◽  
2011 ◽  
Vol 42 (2-3) ◽  
pp. 75-91 ◽  
Author(s):  
Tomasz Bajda ◽  
Tomasz Marchlewski ◽  
Maciej Manecki
Keyword(s):  
Ion Exchange ◽  
Aqueous Solutions ◽  
Phosphate Concentration ◽  
High Concentration ◽  
Exchange Effect ◽  
System A ◽  
New Phase

Pyromorphite formation from montmorillonite adsorbed lead The reaction of Pb-adsorbed montmorillonite with aqueous solutions of PO4 and Cl ions results in the decrease in phosphate concentration associated with the formation of a new phase - pyromorphite Pb5(PO4)3Cl. Pyromorphite crystals range in size from hundreds of nm to several tens of μm, depending on the PO4, K, and Ca concentrations in the reacting system. A strong ion-exchange effect of K+ and Ca2+ cations on desorption of Pb2+ from Pb-adsorbed montmorillonite was observed. Also, a high concentration of cations leads to a rapid desorption of Pb and the formation of fine pyromorphite crystals. In contrast, low PO4, K and Ca concentrations result in the formation of relatively large euhedral crystals. Final Pb concentrations are much lower in experimental sets than in control experiments with no phosphate present.

scholarly journals Application of spheroidal agglomerates of γ-Al2O3 in the fluoride removal from aqueous medium

2019 ◽  
Vol 29 ◽  
pp. 1-16
Author(s):  
Rafael Romero Toledo ◽  
Víctor Ruiz Santoyo ◽  
Ulises Zurita Luna ◽  
Gustavo Rangel Porras ◽  
Merced Martínez Rosales
Keyword(s):  
Aqueous Medium ◽  
Fluoride Removal ◽  
Batch Experiments ◽  
Activated Alumina ◽  
27Al Nmr ◽  
First Order ◽  
First Order Kinetics ◽  
Effective Removal ◽  
Adsorption Processes ◽  
Ft Ir

A spheroidal agglomerate γ-Al2O3 adsorbent obtained from pseudoboehmite for effective removal of fluoride from aqueous medium was investigated in the present study. The surface properties were characterized by several techniques: XRD, physisorption of N2, FE-SEM/EDS, 27Al NMR, FT-IR Pyridine adsorption, PZ and particle size. Batch experiments were conducted and they were compared with a commercial activated alumina (AA). The process was carried out at pH 5, 7, and 9, then at 25 and 35 ºC. Batch experimental results indicated that the spheroidal agglomerates of γ-Al2O3 remove up to 15 mg/g with a higher adsorption capacity than AA of 13 mg/g, at pH 5, studied at 25 and 35 °C. The F− adsorption processes in γ-Al2O3 and AA followed the pseudo-first-order kinetics and the Langmuir isotherm. The results showed an adsorbent effective for removal of F−.

Regeneration Effect of Fluoride-Rich Granular Activated Alumina on Desorption Regent NaOH Solution

2013 ◽  
Vol 316-317 ◽  
pp. 653-656
Author(s):  
Bai Jie Niu ◽  
Wen Ming Ding ◽  
Dan Dang
Keyword(s):  
Adsorption Capacity ◽  
Sodium Hydroxide Solution ◽  
Fluoride Concentration ◽  
Column Experiment ◽  
Fluoride Removal ◽  
Activated Alumina ◽  
Optimal Method ◽  
Column Adsorption ◽  
Naoh Solution ◽  
Regeneration Effect

As an effective adsorbent, granular activated alumina (GAA) has been widely used in defluoridation. In order to reduce cost and operate environment-friendly, the adsorbent should be regenerated. In this paper, column experiment was done to characterize the fluoride removal properties and to develop an optimal method to regenerate fluoride-rich modified activated alumina (MGAA). The MGAA can be regenerated by utilizing sodium hydroxide solution desorption, deionized water washing and ferric sulfate reactivation and then used for futher defluoride operation. The influence of the concentration of desorption agent (NaOH solution) and desorbing time on desorption rate and the adsorption capacity of regenerated MGAA were studied. The optimal desorption condition was: 1% NaOH solution for desorption agent, desorbing time in 1.5h.In addition, when the regenerated MGAA was used again for column adsorption test, its adsorption capacity reached 94% of that of original sorbent in 1mg/L outlet fluoride concentration.

scholarly journals ADSORPTIVE REMOVAL OF TRACE CONCENTRATION OF FLUORIDE FROM WATER USING CERIUM LOADED DRIED ORANGE JUICE RESIDUE

2018 ◽  
Vol 23 (1) ◽  
pp. 43-48
Author(s):  
Hari Paudyal ◽  
Katsutoshi Inoue
Keyword(s):  
Orange Juice ◽  
Optimum Operating ◽  
Fluoride Removal ◽  
Fluoride Ion ◽  
Maximum Adsorption Capacity ◽  
High Concentration ◽  
Trace Concentration ◽  
Promising Alternative ◽  
X Ray ◽  
Equilibrium Data

 Two adsorbents for fluoride ion removal were developed from dried orange juice residue (DOJR) after loading Ce(III) and Ce(IV) in this study. The characterization of adsorbents was done by an energy dispersive X-ray spectroscopy, X-ray diffraction analysis, electron microscopy and chemical analysis. The experimental results indicated that the fluoride removal efficiency of both the adsorbents was influenced significantly by pH and the optimum operating pH was found to be 4. The equilibrium data were well fitted with Langmuir isotherm model and the maximum adsorption capacity of Ce(III)-DOJR and Ce(IV)-DOJR for fluoride were evaluated to be 0.67 and 1.22 mmol/g, respectively. Leakage of cerium from Ce(IV)-DOJR was negligible for trace concentration of fluoride but it was significant for high concentration of fluoride at pH below 3 resulting fluoride precipitation. Therefore, cerium-loaded DOJR investigated in this study can be considered as an efficient, environmentally benign and promising alternative for the treatment of fluoride contaminated with trace amount of fluoride ion.

Arsenic in drinking water-problems and solutions

1999 ◽  
Vol 40 (2) ◽  
pp. 69-76 ◽  
Author(s):  
T. Viraraghavan ◽  
K. S. Subramanian ◽  
J. A. Aruldoss
Keyword(s):  
United States ◽  
Drinking Water ◽  
Ion Exchange ◽  
Environmental Protection Agency ◽  
The United States ◽  
Activated Alumina ◽  
Column Studies ◽  
Maximum Contaminant Level ◽  
Aluminum Salts ◽  
Contaminant Level

The current United States maximum contaminant level for arsenic in drinking water is set at 50 μg/l. Because of the cancer risks involved, Canada has already lowered the maximum contaminant level to 25 μg/l; the United States Environmental Protection Agency is reviewing the current allowable level for arsenic with a view of lowering it significantly. Various treatment methods have been adopted to remove arsenic from drinking water. These methods include 1) adsorption-coprecipitation using iron and aluminum salts, 2) adsorption on activated alumina, activated carbon, and activated bauxite, 3) reverse osmosis, 4) ion exchange and 5) oxidation followed by filtration. Because of the promise of oxidation-filtration systems, column studies were conducted at the University of Regina to examine oxidation with KMnO4 followed by filtration using manganese greensand and iron-oxide coated sand to examine the removal of arsenic from drinking water; these results were compared with the data from ion exchange studies. These studies demonstrated that As (III) could be reduced from 200 μg/l to below 25 μg/l by the manganese greensand system. In the case of manganese greensand filtration, addition of iron in the ratio of 20:1 was found necessary to achieve this removal.

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