Defluoridation of drinking water using chemically modified bentonite clay

Kamble, Sanjay P.; Dixit, Priyadarshini; Rayalu, Sadhana; Labhsetwar, Nitin

doi:10.1016/j.desal.2009.01.031

Cited by 125 publications

(41 citation statements)

References 25 publications

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“…AO-Bent 5 and AO-Mont 5 has shown fluoride removal capacity of 0.7 mg/g and 1.16 mg /g which means approximately five and nine fold increase in fluoride removal capacity respectively as compared to their respective unmodified clays. In addition, AO-modified clays has shown significant removal efficiency over a wider range of pH (3)(4)(5)(6)(7)(8)(9)(10)(11) for AO-Bent and (4-9) for AO-Mont. Bicarbonate ion has shown to have strong competitive effect for fluoride adsorption as compared to other anions studied.…”

Section: Discussionmentioning

confidence: 99%

“…However, excessive exposure of fluoride can lead to a number of adverse effects such as dental and skeletal fluorosis [1,2,[6][7][8]. Prolonged exposure 200 increases the risk of developing crippling skeletal fluorosis and other non-skeletal effects such as on renal, gastrointestinal and immune systems.…”

Section: Introductionmentioning

confidence: 99%

“…Clays are inexpensive and consequently can be used in less developed countries, especially in rural areas but usually have low effectiveness in removing fluoride (<1 mg g -1 ) [29][30][31]. Their fluoride removal capacities can be increased through the process of surface modification, such as loading with multivalent metallic cations [6,28]. Several studies reported that aluminum has strong affinity towards fluoride.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effective fluoride adsorption by aluminum oxide modified clays: Ethiopian bentonite vs commercial montmorillonite

Dessalegne¹,

Zewge²,

Mammo³

et al. 2018

Bull. Chem. Soc. Eth.

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ABSTRACT. This study focuses on the chemical modification of Ethiopian bentonite and commercial montmorillonite with aluminum oxi-hydroxide (AO) for the purpose of defluoridation from aqueous solution. The chemical modification was achieved by preparing AO-modified adsorbents at different pH values. The adsorbent materials were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF) and point of zero charge (PZC). From the modified adsorbents, AO-Mont at pH 5 (AO-Mont 5) showed a slight shift of d001 at 2θ = 7.5º reflection toward the lower angle 2θ = 7.0º as a result of the Al2O3 insertion into interlayer space. The elemental composition from XRF further showed the increment of Al content accompanied with a decrease in the exchangeable cations in the modified samples and higher content of Al was observed in AO-Mont 5. In addition, the PZC initially 8.5 and 2.5 for raw bentonite and montmorillonite clays were increased to 10 and 8.5 in AO-Bent 5 and AO-Mont 5, respectively. Adsorption of fluoride on these modified adsorbents was studied as a function of preparation pH, contact time, solution pH and co-existing anions. AO-Mont prepared at pH 5, which contained higher content of Al resulted better fluoride removal performance. AO-Bent 5 and AO-Mont 5 have shown five and nine fold increase in fluoride removal capacity, respectively as compared to their respective unmodified clays. The experimental data fitted well with Freundlich adsorption isotherm model which indicated that the surface of the adsorbent is heterogeneous and adsorption of fluoride followed a multilayer sorption. Hence AO-modified Bent and Mont adsorbents prepared at pH 5 can be considered as potential adsorbents for defluoridation from drinking water.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effective fluoride adsorption by aluminum oxide modified clays: Ethiopian bentonite vs commercial montmorillonite

Dessalegne¹,

Zewge²,

Mammo³

et al. 2018

Bull. Chem. Soc. Eth.

View full text Add to dashboard Cite

show abstract

“…Linear regression analysis has been frequently employed in accessing the quality of fits and adsorption performance for fluoride removal from aqueous solutions (Fan et al 2003;Onyango et al 2004;Kamble et al 2009;Foo and Hameed 2010). The fitting validity of different models was tested in linearized forms using coefficient of determination.…”

Section: Introductionmentioning

confidence: 99%

Isotherm investigation for the sorption of fluoride onto Bio-F: comparison of linear and non-linear regression method

Yadav

Singh

2017

Appl Water Sci

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A comparison of the linear and non-linear regression method in selecting the optimum isotherm among three most commonly used adsorption isotherms (Langmuir, Freundlich, and Redlich-Peterson) was made to the experimental data of fluoride (F) sorption onto Bio-F at a solution temperature of 30 ± 1°C. The coefficient of correlation (r 2 ) was used to select the best theoretical isotherm among the investigated ones. A total of four Langmuir linear equations were discussed and out of which linear form of most popular Langmuir-1 and Langmuir-2 showed the higher coefficient of determination (0.976 and 0.989) as compared to other Langmuir linear equations. Freundlich and Redlich-Peterson isotherms showed a better fit to the experimental data in linear least-square method, while in non-linear method Redlich-Peterson isotherm equations showed the best fit to the tested data set. The present study showed that the non-linear method could be a better way to obtain the isotherm parameters and represent the most suitable isotherm. Redlich-Peterson isotherm was found to be the best representative (r 2 = 0.999) for this sorption system. It is also observed that the values of b are not close to unity, which means the isotherms are approaching the Freundlich but not the Langmuir isotherm.

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“…The sorption capacity of the acid activated clay for fluoride ranged between 0.0450 and 0.0557mg/g at different temperatures. Montmorillonite has also been used as adsorbent for removal of fluoride in water, [11] and modification of montmorillonite using lanthanide, magnesium and manganese can increase the adsorption capacity for fluoride removal [12]. [13] conducted a comparative study for the removal of fluoride using activated silica gel (ASiG) and activated rice husk ash (ARHA) as adsorbents through batch studies.…”

Section: Introductionmentioning

confidence: 99%

Temperature Effects and Thermodynamic Adsorption of Flouride on Activated Coconut Shell Carbon, Activated Montmorillonite Clay and Rice Husk Ash

2017

International Journal of Advanced Research in Chemical Science

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Defluoridation of drinking water using chemically modified bentonite clay

Cited by 125 publications

References 25 publications

Effective fluoride adsorption by aluminum oxide modified clays: Ethiopian bentonite vs commercial montmorillonite

Effective fluoride adsorption by aluminum oxide modified clays: Ethiopian bentonite vs commercial montmorillonite

Isotherm investigation for the sorption of fluoride onto Bio-F: comparison of linear and non-linear regression method

Temperature Effects and Thermodynamic Adsorption of Flouride on Activated Coconut Shell Carbon, Activated Montmorillonite Clay and Rice Husk Ash

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