scholarly journals Dicarboxylic acid cross-linked metal ion decorated bentonite clay and chitosan for fluoride removal studies

RSC Advances ◽  
2020 ◽  
Vol 10 (28) ◽  
pp. 16791-16803
Author(s):  
Ammavasi Nagaraj ◽  
Kriveshini Pillay ◽  
Sadasivuni Kishor Kumar ◽  
Mariappan Rajan
Keyword(s):  
Dicarboxylic Acid ◽  
Adsorption Capacity ◽  
Metal Ion ◽  
Bentonite Clay ◽  
Fluoride Removal ◽  
Fluoride Adsorption ◽  
Removal Studies

The adsorbent CeBC-A@CS nanocomposite has the maximum fluoride adsorption capacity.

scholarly journals Mg-Al Mixed Oxide Adsorbent Synthesized Using FCT Template for Fluoride Removal from Drinking Water

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jifa Liu ◽  
Ping Zhao ◽  
Yue Xu ◽  
Xibin Jia
Keyword(s):  
Drinking Water ◽  
Adsorption Capacity ◽  
Mixed Oxide ◽  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
Molar Ratio ◽  
Fluoride Removal ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Fluoride Adsorption

To make full use of natural waste, a novel Mg-Al mixed oxide adsorbent was synthesized by the dip-calcination method using the fluff of the chinar tree (FCT) and an Mg(II) and Al(III) chloride solution as raw materials. The adsorbents were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The effects of the Mg/Al molar ratio and calcination temperature on the performance of the novel Mg-Al mixed oxide adsorbent were investigated. The optimized Mg-Al mixed oxide adsorbent had a Langmuir adsorption capacity of 53 mg/g. This adsorption capacity was higher than that of the separate Mg oxide and Al oxide. The synergy between Mg and Al is beneficial to the adsorption performance of the material. The fluoride adsorption capacity of the optimized Mg-Al mixed oxide adsorbent is only slightly affected by ions such as Cl−, NO3−, SO42−, Na+, and K+and is excellent for use in recycling and real water. The hydroxyl groups on the surface of the Mg-Al mixed oxide adsorbent play a key role in the adsorption of fluorine. The as-obtained novel Mg-Al mixed oxide adsorbent is an efficient and environmentally friendly agent for fluoride removal from drinking water.

scholarly journals Repeated Heat Regeneration of Bone Char for Sustainable Use in Fluoride Removal from Drinking Water

Healthcare ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 143 ◽  
Author(s):  
H. Herath ◽  
Tomonori Kawakami ◽  
Masamoto Tafu
Keyword(s):  
Adsorption Capacity ◽  
Low Cost ◽  
Sustainable Use ◽  
Chemical Precipitation ◽  
Fluoride Removal ◽  
Bone Char ◽  
Fluoride Adsorption ◽  
Heat Regeneration ◽  
Recovery Percentage ◽  
Regeneration Of Bone

The effectiveness of regenerated chicken bone char (CBC) in fluoride removal was investigated in the present study. Heat treatment was studied as the regeneration method. Results revealed that the CBC regenerated at 673 K yielded the highest fluoride adsorption capacity, hence, 673 K was the best regenerating temperature. The study continued up to five regeneration cycles at the best regenerating temperature; 673 K. The CBC accounted to 16.1 mg F/g CBC as the total adsorption capacity after five regeneration cycles. The recovery percentage of CBC reduced from 79% at the first regeneration to 4% after five regeneration cycles. The hydroxyapatite structure of CBC was not changed during the fluoride adsorption by five regeneration cycles. The ion exchange incorporated with the chemical precipitation occurred during the fluoride adsorption. The repeated regeneration of CBC is possible and it could be used as a low cost defluoridation technique to minimize the wastage of bone char.

Removal of Fluoride from Drinking Water by Gel Composite of Metal Ion and Humic Acid Adsorbent

2013 ◽  
Vol 726-731 ◽  
pp. 695-699
Author(s):  
Li Hong ◽  
Si Xiang Wang ◽  
Yong Liu ◽  
Yue Chun Zhang
Keyword(s):  
Drinking Water ◽  
Humic Acid ◽  
Contact Time ◽  
Metal Ion ◽  
Fluoride Removal ◽  
Batch Adsorption ◽  
Solution Ph ◽  
Adsorption Method ◽  
Sem Images ◽  
Fluoride Adsorption

Humic acid adsorbent modified with metal ions was prepared by gel polymerization and named gel composite of metal ion and humic acid, which abbreviated GCMH to uptake fluoride from drinking water. The samples were measured by X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images. Fluoride adsorption onto the synthesized samples was investigated by batch adsorption method. In previous works, detailed studies were carried out to investigate the effect of contact time, adsorbent dose, initial solution pH, temperatures and co-existing anions. The maximum fluoride removal was obtained at pH7. Presence of HCO3− adversely affected the adsorption of fluoride. The optimum absorption conditions were at the dose of 10g/L, temperature of water of 55°Cand contact time of 6hs.

Granulation of Fe-Al-Ce nano-adsorbent for fluoride removal from drinking water using inorganic binder

2013 ◽  
Vol 13 (5) ◽  
pp. 1309-1316 ◽  
Author(s):  
Chao-Li Su ◽  
Lin Chen ◽  
Ting-Jie Wang ◽  
Li-Xin Yu ◽  
Yong Jin
Keyword(s):  
Adsorption Capacity ◽  
Active Sites ◽  
Organic Binder ◽  
Hydroxyl Group ◽  
Fluoride Removal ◽  
Great Loss ◽  
Fluoride Adsorption ◽  
High Fluoride ◽  
Nano Adsorbent ◽  
Extrusion Method

Nano-adsorbents usually have high fluoride adsorption capacity. However, they cannot be used in packed beds because of their low hydraulic conductivity. Granulation with organic binder usually causes a great loss of adsorption capacity due to the active sites of the adsorbent being extensively occupied by the organic binder. Using inorganic sol as a binder is expected to have a potential for reducing the loss of adsorption capacity. In this paper, aluminium, zirconium, titanium and silica sol were employed as binders for Fe-Al-Ce nano-adsorbent granulation. The nano-adsorbent was mixed with sol and dried to form lumps, then calcinated and ground into powder. The morphology, adsorption capacity and structure of the compound powder were analysed. As an optimization, aluminium sol was selected as a binder in the granulation of Fe-Al-Ce nano-adsorbent using extrusion method. The effects of sol on the adsorbent and the granule structure were characterized. The granules showed a high adsorption capacity, reaching over 90% capacity of Fe-Al-Ce nano-adsorbent, much higher than that of using acrylic-styrene copolymer latex as a binder in our previous research. It is inferred that aluminium sol is a suitable binder which does no damage to the active hydroxyl group of Fe-Al-Ce adsorbent.

scholarly journals Synthesis of a Novel Ce-bpdc for the Effective Removal of Fluoride from Aqueous Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Changqing Zhao ◽  
Yanwei Cui ◽  
Fang Fang ◽  
Si Ok Ryu ◽  
Jiarui Huang
Keyword(s):  
Adsorption Capacity ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Binding Capacity ◽  
Fluoride Removal ◽  
Maximum Adsorption Capacity ◽  
Fluoride Ions ◽  
X Ray ◽  
Fluoride Adsorption

Ce-1,1′-biphenyl-4,4′-dicarboxylic acid (Ce-bpdc), a novel type of metal organic framework, was synthesized and applied to remove excessive fluoride from water. The structure and morphology of Ce-bpdc were measured by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The effects, such as saturated adsorption capacity, HCO3-, and pH, were investigated. The optimal pH value for fluoride adsorption was the range from 5 to 6. The coexisting bicarbonate anions have a little influence on fluoride removal. The fluoride adsorption over the Ce-bpdc adsorbent could reach its equilibrium in about 20 min. The Ce-bpdc coordination complex exhibited high binding capacity for fluoride ions. The maximum adsorption capacity calculated from Langmuir model was high up to 45.5 mg/g at 298 K (pH = 7.0) and the removal efficiency was greater than 80%. In order to investigate the mechanism of fluoride removal, various adsorption isotherms such as Langmuir and Freundlich were fitted. The experimental data revealed that the Langmuir isotherm gave a more satisfactory fit for fluoride removal. Finally, the tested results of ground water samples from three places, Yuefang, Jiangji, and Sanyi which exhibited high removal efficiency, also demonstrate the potential utility of the Ce-bpdc as an effective adsorbent.

scholarly journals Adsorption of fluoride from industrial wastewater using polymer adsorbents: a review

2021 ◽  
Vol 945 (1) ◽  
pp. 012068
Author(s):  
Chee Yung Pang ◽  
Gulnaziya Issabayeva ◽  
Chen Hwa Low ◽  
Mee Chu Wong
Keyword(s):  
Adsorption Capacity ◽  
Industrial Wastewater ◽  
Membrane Filtration ◽  
Chemical Precipitation ◽  
Fluoride Removal ◽  
High Adsorption ◽  
Polymeric Adsorbents ◽  
Fluoride Adsorption ◽  
High Adsorption Capacity ◽  
Removal Technologies

Abstract Fluoride pollution in ground and surface water originates from naturally occurring reactions and industrial activities such as the disposal of industrial wastewater. Amongst different fluoride removal technologies including chemical precipitation, membrane filtration, ion exchange processes, and electrodialysis, adsorption is an attractive method for fluoride removal from wastewater due to its low operational cost, simplicity, and good sustainability. Various adsorbents are used for fluoride removal including, metal oxides and hydroxide, carbonaceous adsorbents, zeolite, polysaccharides, and polyresin adsorbents. This review studies the application of modified polysaccharides and polyresin adsorbents for the removal of fluoride from wastewater. The relationship between the adsorption conditions and the resulting adsorption capacity is thoroughly discussed. Based on the reported studies, modified polysaccharides and polyresins adsorbents can effectively remove fluoride from wastewater achieving high adsorption capacity, the highest being 92.39 mg/g for aluminum impregnated amberlite at pH 3. Furthermore, aluminum impregnated adsorbents reported a higher fluoride adsorption capacity than other modification methods where the three adsorbents with the highest fluoride adsorption capacity are: aluminum impregnated amberlite 92.39 mg/g at pH 3> zirconium immobilized crossed linked chitosan 48.26 mg/g at pH 6 > chitosan/aluminum hydroxide beads 17.68 mg/g at pH 4. In addition, polymeric adsorbents are also highly sustainable as they can be regenerated multiple times to be reused. Therefore, the high adsorption capacity and good regeneration potential allow polymeric adsorbents to serve as promising and sustainable adsorbents to remove fluoride from industrial wastewater.

Fluoride removal by a hybrid fluoride-selective adsorbent

2014 ◽  
Vol 14 (6) ◽  
pp. 1133-1141 ◽  
Author(s):  
Geetanjali Tomar ◽  
Arushi Thareja ◽  
Sudipta Sarkar
Keyword(s):  
Adsorption Capacity ◽  
Hydraulic Properties ◽  
Mechanical Stability ◽  
Fluoride Removal ◽  
Maximum Adsorption Capacity ◽  
Activated Alumina ◽  
Fluoride Adsorption ◽  
Effective Removal ◽  
Synthetic Solution ◽  
High Concentrations

High concentrations of fluoride in groundwater have become a global environmental challenge. Out of the various methods developed for effective removal of fluoride adsorption using activated alumina (AA) is popular as it has a low initial cost. AA offers excellent chemical and mechanical stability, selectivity for fluoride, favorable hydraulic properties, regenerability but offers lower adsorption capacity as there is reduction in material and capacity with an increased presence of aluminum. Hydroxyapatite nanoparticles have been found to possess high adsorption capacity for fluoride but they lack mechanical stability and favorable hydraulic properties. In this study, we synthesized a hybrid adsorbent, modified activated alumina, prepared by dispersing nanoparticles of hydroxyapatite inside AA granules. The hybrid adsorbent possesses a maximum adsorption capacity of 14.4 mg F/g which is at least five times higher than that of the virgin AA which has been used extensively for fluoride removal. A column run carried out on the hybrid adsorbent with a synthetic solution containing 3 mg/L fluoride lasted for 450 bed volumes before a breakthrough of 1.5 mg/L was observed. The exhausted adsorbent could be fully regenerated in a column within six bed volumes using commonly available innocuous chemicals. The study will contribute to the field of effective removal of fluoride from contaminated drinking water.

scholarly journals FLUORIDE REMOVAL USING ACTIVATED ALUMINA: A CASE STUDY OF BHOOMA CHOTA WATER

2013 ◽  
Vol 21 (21) ◽  
pp. 61-77
Author(s):  
R. AGRAWAL ◽  
M. K. MISHRA ◽  
K. MARGANDAN ◽  
K. SINGH ◽  
R. ACHARYA ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Absorption Capacity ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Least Square ◽  
Fluoride Removal ◽  
Activated Alumina ◽  
Surface Absorption ◽  
Fluoride Adsorption ◽  
Pseudo Second Order

The adsorption of fluoride, from a fluoride, contaminated groundwater sample from the village, Bhooma Chota, District Sikar, in the State of Rajasthan, India, has been studied using alumina grade DF-101. The fluoride adsorption capacity (q1) has been fitted into the pseudo-first-order adsorption, pseudo-second-order adsorption, Elovich, and intraparticle diffusion models. It has been found that the kinetic data fits best in the pseudo-second-order rate equation giving a very high correlation coefficient (R2 = 0.991). the modeled fluoride absorption capacity (q1) has been calculated from the various equations using the constants derived from the least square regression plots. The calculated q1 values, model the experimental data very well, for the pseudo-second-order and Elovich equations, as is evident from the sum of square error calculations. Fluoride removal is through a combination of surface absorption and intraparticle diffusion. A study of the fluoride removal process with increasing dosage of activated alumina reveals that though the percentage of fluoride removal increases with activated alumina, the adsorption capacity at equilibrium decreases. The minimum dosage of activated alumina which causes the maximum percentage removal of fluoride from water, while at the same time brings forth its highest equilibrium absorption capacity has been determined.

Chemically activated cow bone for increased fluoride removal from drinking water

2016 ◽  
Vol 6 (2) ◽  
pp. 215-223 ◽  
Author(s):  
Teshome L. Yami ◽  
Elizabeth C. Butler ◽  
David A. Sabatini
Keyword(s):  
Drinking Water ◽  
Adsorption Capacity ◽  
Thermal Activation ◽  
Chemical Activation ◽  
Unit Mass ◽  
Fluoride Removal ◽  
Bone Char ◽  
Fluoride Adsorption ◽  
Removal Capacity ◽  
Cow Bone

Thermally activated cow bone is widely utilized for treating fluoride impacted drinking water to meet the World Health Organization guideline value of 1.5 mg/L. However, the fluoride removal capacity of bone char is low, leaving room for further improvement. This study, therefore, strives to improve the fluoride adsorption capacity of cow bone by using chemical activation in place of thermal activation. Chemically activated cow bones (CABs) had, on average, a four-fold higher fluoride adsorption capacity than bone char. Characterization of the most effective CAB were made to explore potential reasons for the increased fluoride adsorption capacity. The X-ray diffraction pattern of the CAB showed formation of bassanite and monetite minerals which may be responsible for the higher fluoride adsorption capacity. Chemical activation is also a lower-cost production process than the thermal activation of cow bone. Further, a higher mass of media was recovered per unit mass of starting material during chemical activation. Therefore, this research shows that increased fluoride removal capacity can be achieved with chemical activation of cow bone while reducing activation costs and greatly increasing product yield per unit mass of starting material, all of which support further evaluation and field testing of this material.

Hydrothermal synthesis of a mineral-substituted hydroxyapatite nanocomposite material for fluoride removal from drinking water

2018 ◽  
Vol 42 (15) ◽  
pp. 12711-12721 ◽  
Author(s):  
Ammavasi Nagaraj ◽  
Murugan A. Munusamy ◽  
Mukhtar Ahmed ◽  
S. Suresh Kumar ◽  
Mariappan Rajan
Keyword(s):  
Drinking Water ◽  
Hydrothermal Synthesis ◽  
Adsorption Capacity ◽  
Nanocomposite Material ◽  
Fluoride Removal ◽  
Fluoride Adsorption ◽  
High Fluoride

Mineral substituted hydroxyapatite (mHAp) nanocomposite was synthesized and it shows high fluoride adsorption capacity.

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