Effects of the molar ratio of hydroxide and fluoride to Al(III) on fluoride removal by coagulation and electrocoagulation

C. Y. Hu; S. L. Lo; W. H. Kuan

doi:10.1016/j.jcis.2004.09.045

Effects of the molar ratio of hydroxide and fluoride to Al(III) on fluoride removal by coagulation and electrocoagulation

C. Y. Hu, S. L. Lo, W. H. Kuan

Research output: Contribution to journal › Article › peer-review

119 Citations (Scopus)

Abstract

The effect of the molar ratio of hydroxide and fluoride ions to Al(III) ions (γ_OH and γ_F) on coagulation and electrocoagulation (EC) was studied to solve the problem of the over addition of acid or base. The efficiency of defluoridation was approximately 100% when the sum of γ_OH and γ_F (γ_OH+F) was close to 3. This finding reveals that the fluoride ions and the hydroxide ions can co-precipitate with Al(III) ions and the formula of the precipitate is Al_nF_m(OH)_3n-m. However, when γ_OH was less than 2.4, the defluoridation efficiency, given that γ_OH+F=3, dropped as γ_OH fell, because the amount of aluminum polymer formed dropped. The efficiency of defluoridation of EC exceeded that of coagulation for equal γ_OH and γ_OH+F, when γ_OH+F>3, proving the existence of an electrocondensation effect.

Original language	English
Pages (from-to)	472-476
Number of pages	5
Journal	Journal of Colloid and Interface Science
Volume	283
Issue number	2
DOIs	https://doi.org/10.1016/j.jcis.2004.09.045
Publication status	Published - Mar 15 2005
Externally published	Yes

Keywords

Aluminum
Coagulation
Defluoridation
Electrocoagulation
Fluoride
Molar ratio

ASJC Scopus subject areas

Colloid and Surface Chemistry
Physical and Theoretical Chemistry
Surfaces and Interfaces

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10.1016/j.jcis.2004.09.045

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title = "Effects of the molar ratio of hydroxide and fluoride to Al(III) on fluoride removal by coagulation and electrocoagulation",

abstract = "The effect of the molar ratio of hydroxide and fluoride ions to Al(III) ions (γOH and γF) on coagulation and electrocoagulation (EC) was studied to solve the problem of the over addition of acid or base. The efficiency of defluoridation was approximately 100% when the sum of γOH and γF (γOH+F) was close to 3. This finding reveals that the fluoride ions and the hydroxide ions can co-precipitate with Al(III) ions and the formula of the precipitate is AlnFm(OH)3n-m. However, when γOH was less than 2.4, the defluoridation efficiency, given that γOH+F=3, dropped as γOH fell, because the amount of aluminum polymer formed dropped. The efficiency of defluoridation of EC exceeded that of coagulation for equal γOH and γOH+F, when γOH+F>3, proving the existence of an electrocondensation effect.",

keywords = "Aluminum, Coagulation, Defluoridation, Electrocoagulation, Fluoride, Molar ratio, Aluminum, Coagulation, Defluoridation, Electrocoagulation, Fluoride, Molar ratio",

author = "Hu, {C. Y.} and Lo, {S. L.} and Kuan, {W. H.}",

year = "2005",

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doi = "10.1016/j.jcis.2004.09.045",

language = "English",

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T1 - Effects of the molar ratio of hydroxide and fluoride to Al(III) on fluoride removal by coagulation and electrocoagulation

AU - Hu, C. Y.

AU - Lo, S. L.

AU - Kuan, W. H.

PY - 2005/3/15

Y1 - 2005/3/15

N2 - The effect of the molar ratio of hydroxide and fluoride ions to Al(III) ions (γOH and γF) on coagulation and electrocoagulation (EC) was studied to solve the problem of the over addition of acid or base. The efficiency of defluoridation was approximately 100% when the sum of γOH and γF (γOH+F) was close to 3. This finding reveals that the fluoride ions and the hydroxide ions can co-precipitate with Al(III) ions and the formula of the precipitate is AlnFm(OH)3n-m. However, when γOH was less than 2.4, the defluoridation efficiency, given that γOH+F=3, dropped as γOH fell, because the amount of aluminum polymer formed dropped. The efficiency of defluoridation of EC exceeded that of coagulation for equal γOH and γOH+F, when γOH+F>3, proving the existence of an electrocondensation effect.

AB - The effect of the molar ratio of hydroxide and fluoride ions to Al(III) ions (γOH and γF) on coagulation and electrocoagulation (EC) was studied to solve the problem of the over addition of acid or base. The efficiency of defluoridation was approximately 100% when the sum of γOH and γF (γOH+F) was close to 3. This finding reveals that the fluoride ions and the hydroxide ions can co-precipitate with Al(III) ions and the formula of the precipitate is AlnFm(OH)3n-m. However, when γOH was less than 2.4, the defluoridation efficiency, given that γOH+F=3, dropped as γOH fell, because the amount of aluminum polymer formed dropped. The efficiency of defluoridation of EC exceeded that of coagulation for equal γOH and γOH+F, when γOH+F>3, proving the existence of an electrocondensation effect.

KW - Aluminum

KW - Coagulation

KW - Defluoridation

KW - Electrocoagulation

KW - Fluoride

KW - Molar ratio

KW - Aluminum

KW - Coagulation

KW - Defluoridation

KW - Electrocoagulation

KW - Fluoride

KW - Molar ratio

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SN - 0021-9797

VL - 283

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JF - Journal of Colloid and Interface Science

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ER -

Effects of the molar ratio of hydroxide and fluoride to Al(III) on fluoride removal by coagulation and electrocoagulation

Abstract

Keywords

ASJC Scopus subject areas

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