Removal of fluoride ions from aqueous solution at low pH using schwertmannite

Akbar Eskandarpour, Maurice S. Onyango, Aoyi Ochieng, Shigeo Asai

Research output: Contribution to journalArticle

131 Citations (Scopus)

Abstract

Wastewater containing fluoride requires polishing after precipitation/coagulation treatment in order to meet stringent environmental legislation. Accordingly, adsorption characteristics of fluoride onto schwertmannite adsorbent were studied in a batch system with respect to changes in initial concentration of fluoride, equilibrium pH of sample solution, adsorbent dosage and co-existing ions. Equilibrium adsorption data were obtained at 295.6, 303 and 313K, and are interpreted in terms of two-site Langmuir, Freundlich, Langmuir–Freundlich, Redlich–Peterson, Tóth and Dubinin–Radushkevitch isotherm models. The experimental and equilibrium modeling results revealed that the capacity of schwertmannite for fluoride is high but insensitive to changes in solution temperature. An increase in equilibrium pH of sample solution reduced significantly the fluoride removal efficiency. In binary component systems, inner-sphere complex forming species had negative effects on fluoride adsorption while outer-sphere complex forming species improved slightly the fluoride removal efficiency. The schwertmannite adsorbent was regenerable and had the ability to lower the fluoride concentration to acceptable levels.
Original languageEnglish
Pages (from-to)571-579
Number of pages9
JournalJournal of Hazardous Materials
Volume152
Issue number2
DOIs
Publication statusPublished - 2008

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schwertmannite
Fluorides
fluoride
Adsorbents
aqueous solution
Ions
Adsorption
ion
Coagulation
Polishing
Isotherms
Wastewater
adsorption
environmental legislation
removal
Waste Water
Legislation
coagulation
Temperature
isotherm

Cite this

Eskandarpour, Akbar ; Onyango, Maurice S. ; Ochieng, Aoyi ; Asai, Shigeo. / Removal of fluoride ions from aqueous solution at low pH using schwertmannite. In: Journal of Hazardous Materials. 2008 ; Vol. 152, No. 2. pp. 571-579.
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abstract = "Wastewater containing fluoride requires polishing after precipitation/coagulation treatment in order to meet stringent environmental legislation. Accordingly, adsorption characteristics of fluoride onto schwertmannite adsorbent were studied in a batch system with respect to changes in initial concentration of fluoride, equilibrium pH of sample solution, adsorbent dosage and co-existing ions. Equilibrium adsorption data were obtained at 295.6, 303 and 313K, and are interpreted in terms of two-site Langmuir, Freundlich, Langmuir–Freundlich, Redlich–Peterson, T{\'o}th and Dubinin–Radushkevitch isotherm models. The experimental and equilibrium modeling results revealed that the capacity of schwertmannite for fluoride is high but insensitive to changes in solution temperature. An increase in equilibrium pH of sample solution reduced significantly the fluoride removal efficiency. In binary component systems, inner-sphere complex forming species had negative effects on fluoride adsorption while outer-sphere complex forming species improved slightly the fluoride removal efficiency. The schwertmannite adsorbent was regenerable and had the ability to lower the fluoride concentration to acceptable levels.",
author = "Akbar Eskandarpour and Onyango, {Maurice S.} and Aoyi Ochieng and Shigeo Asai",
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Removal of fluoride ions from aqueous solution at low pH using schwertmannite. / Eskandarpour, Akbar; Onyango, Maurice S.; Ochieng, Aoyi; Asai, Shigeo.

In: Journal of Hazardous Materials, Vol. 152, No. 2, 2008, p. 571-579.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Removal of fluoride ions from aqueous solution at low pH using schwertmannite

AU - Eskandarpour, Akbar

AU - Onyango, Maurice S.

AU - Ochieng, Aoyi

AU - Asai, Shigeo

PY - 2008

Y1 - 2008

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AB - Wastewater containing fluoride requires polishing after precipitation/coagulation treatment in order to meet stringent environmental legislation. Accordingly, adsorption characteristics of fluoride onto schwertmannite adsorbent were studied in a batch system with respect to changes in initial concentration of fluoride, equilibrium pH of sample solution, adsorbent dosage and co-existing ions. Equilibrium adsorption data were obtained at 295.6, 303 and 313K, and are interpreted in terms of two-site Langmuir, Freundlich, Langmuir–Freundlich, Redlich–Peterson, Tóth and Dubinin–Radushkevitch isotherm models. The experimental and equilibrium modeling results revealed that the capacity of schwertmannite for fluoride is high but insensitive to changes in solution temperature. An increase in equilibrium pH of sample solution reduced significantly the fluoride removal efficiency. In binary component systems, inner-sphere complex forming species had negative effects on fluoride adsorption while outer-sphere complex forming species improved slightly the fluoride removal efficiency. The schwertmannite adsorbent was regenerable and had the ability to lower the fluoride concentration to acceptable levels.

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