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Fluoride adsorption on γ - Fe2O3 nanoparticles.

Jayarathna L, Bandara A, Ng WJ, Weerasooriya R - J Environ Health Sci Eng (2015)

Bottom Line: Fluoride adsorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at lower pH.Molecular clusters were found to be good agreement with experimental observations.These results show direct chemical interaction with fluoride ions.

View Article: PubMed Central - PubMed

Affiliation: Material Technology Section, Industrial Technology Institute, No 363, Bauddhaloka Mawatha, Colombo 07, Sri Lanka ; Chemical and Environmental System Modeling group, Institute of Fundamental Studies, Hanthana Road, Kandy, Sri Lanka.

ABSTRACT

Background: Fluoride contamination of groundwater, both anthropogenic and natural, is a major problem worldwide and hence its removal attracted much attention to have clean aquatic systems. In the present work, removal of fluoride ions from drinking water tested using synthesized γ-Fe2O3 nanoparticles.

Methods: Nanoparticles were synthesized in co-precipitation method. The prepared particles were first characterized by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). Density functional theory (DFT) calculations on molecular cluster were used to model infrared (IR) vibrational frequencies and inter atomic distances.

Results: The average size of the particles was around 5 nm initially and showed a aggregation upon exposure to the atmosphere for several hours giving average particle size of around 5-20 nm. Batch adsorption studies were performed for the adsorption of fluoride and the results revealed that γ-Fe2O3 nanoparticles posses high efficiency towards adsorption. A rapid adsorption occurred during the initial 15 min by removing about 95 ± 3 % and reached equilibrium thereafter. Fluoride adsorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at lower pH. Fourier transform infrared spectroscopy (FT-IR) was used for the identification of functional groups responsible for the adsorption and revealed that the direct interaction between fluoride and the γ-Fe2O3 particles.

Conclusions: The mechanism for fluoride removal was explained using the dehydoxylation pathway of the hydroxyl groups by the incoming fluoride ion. FT-IR data and other results from the ionic strength dependence strongly indicated that formation of inner-spherically bonded complexes. Molecular clusters were found to be good agreement with experimental observations. These results show direct chemical interaction with fluoride ions.

No MeSH data available.


Related in: MedlinePlus

FTIR spectra of as prepared γ-Fe2O3 particles (dotted line) and the particles treated with saturation of fluoride solution at pH 6 (solid line). These two spectra compare the changes in the system upon adsorption of fluoride in the whole range of 500–4000 cm-1
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Fig3: FTIR spectra of as prepared γ-Fe2O3 particles (dotted line) and the particles treated with saturation of fluoride solution at pH 6 (solid line). These two spectra compare the changes in the system upon adsorption of fluoride in the whole range of 500–4000 cm-1

Mentions: FTIR measurements were carried out on the synthesized and fluoride adsorbed particles in order to characterize the systems with their nature of bonding. At first, the FTIR measurements were done on the bare particles to observe the existing functionalities and that the spectrum is shown by a dashed line in Fig. 3. IR absorption bands observed in the range 450–750 cm-1 are due to Fe-O bond vibrations and two sharp peaks at ~800 and ~900 cm-1 are due to the bending vibrations of O…Fe…O groups. The broad peak at around 3400 cm-1 is due to the hydrogen bonded OH as the surface adsorbed water is present on the particles and this further supported by the bands appearing around 1600 cm-1 [29, 32, 37].Fig. 3


Fluoride adsorption on γ - Fe2O3 nanoparticles.

Jayarathna L, Bandara A, Ng WJ, Weerasooriya R - J Environ Health Sci Eng (2015)

FTIR spectra of as prepared γ-Fe2O3 particles (dotted line) and the particles treated with saturation of fluoride solution at pH 6 (solid line). These two spectra compare the changes in the system upon adsorption of fluoride in the whole range of 500–4000 cm-1
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4513747&req=5

Fig3: FTIR spectra of as prepared γ-Fe2O3 particles (dotted line) and the particles treated with saturation of fluoride solution at pH 6 (solid line). These two spectra compare the changes in the system upon adsorption of fluoride in the whole range of 500–4000 cm-1
Mentions: FTIR measurements were carried out on the synthesized and fluoride adsorbed particles in order to characterize the systems with their nature of bonding. At first, the FTIR measurements were done on the bare particles to observe the existing functionalities and that the spectrum is shown by a dashed line in Fig. 3. IR absorption bands observed in the range 450–750 cm-1 are due to Fe-O bond vibrations and two sharp peaks at ~800 and ~900 cm-1 are due to the bending vibrations of O…Fe…O groups. The broad peak at around 3400 cm-1 is due to the hydrogen bonded OH as the surface adsorbed water is present on the particles and this further supported by the bands appearing around 1600 cm-1 [29, 32, 37].Fig. 3

Bottom Line: Fluoride adsorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at lower pH.Molecular clusters were found to be good agreement with experimental observations.These results show direct chemical interaction with fluoride ions.

View Article: PubMed Central - PubMed

Affiliation: Material Technology Section, Industrial Technology Institute, No 363, Bauddhaloka Mawatha, Colombo 07, Sri Lanka ; Chemical and Environmental System Modeling group, Institute of Fundamental Studies, Hanthana Road, Kandy, Sri Lanka.

ABSTRACT

Background: Fluoride contamination of groundwater, both anthropogenic and natural, is a major problem worldwide and hence its removal attracted much attention to have clean aquatic systems. In the present work, removal of fluoride ions from drinking water tested using synthesized γ-Fe2O3 nanoparticles.

Methods: Nanoparticles were synthesized in co-precipitation method. The prepared particles were first characterized by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). Density functional theory (DFT) calculations on molecular cluster were used to model infrared (IR) vibrational frequencies and inter atomic distances.

Results: The average size of the particles was around 5 nm initially and showed a aggregation upon exposure to the atmosphere for several hours giving average particle size of around 5-20 nm. Batch adsorption studies were performed for the adsorption of fluoride and the results revealed that γ-Fe2O3 nanoparticles posses high efficiency towards adsorption. A rapid adsorption occurred during the initial 15 min by removing about 95 ± 3 % and reached equilibrium thereafter. Fluoride adsorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at lower pH. Fourier transform infrared spectroscopy (FT-IR) was used for the identification of functional groups responsible for the adsorption and revealed that the direct interaction between fluoride and the γ-Fe2O3 particles.

Conclusions: The mechanism for fluoride removal was explained using the dehydoxylation pathway of the hydroxyl groups by the incoming fluoride ion. FT-IR data and other results from the ionic strength dependence strongly indicated that formation of inner-spherically bonded complexes. Molecular clusters were found to be good agreement with experimental observations. These results show direct chemical interaction with fluoride ions.

No MeSH data available.


Related in: MedlinePlus