Fluoride adsorption studies on mixed-phase nano iron oxides prepared by surfactant mediation-precipitation technique
Mohapatra, M., Rout, K., Singh, P., Anand, S., Layek, S., Verma, H.C. and Mishra, B.K. (2011) Fluoride adsorption studies on mixed-phase nano iron oxides prepared by surfactant mediation-precipitation technique. Journal of Hazardous Materials, 186 (2-3). pp. 1751-1757.
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Mixed nano iron oxides powder containing goethite (α-FeOOH), hematite (α-Fe2O3) and ferrihydrite (Fe5HO8·4H2O) was synthesized through surfactant mediation-precipitation route using cetyltrimethyl ammonium bromide (CTAB). The X-ray diffraction, FTIR, TEM, Mössbauer spectroscopy were employed to characterize the sample. These studies confirmed the nano powder contained 77% goethite, 9% hematite and 14% ferrihydrite. Fluoride adsorption onto the synthesized sample was investigated using batch adsorption method. The experimental parameters chosen for adsorption studies were: pH (3.0-10.0), temperature (35-55°C), concentrations of adsorbent (0.5-3.0g/L), adsorbate (10-100mg/L) and some anions. Adsorption of fluoride onto mixed iron oxide was initially very fast followed by a slow adsorption phase. By varying the initial pH in the range of 3.0-10.0, maximum adsorption was observed at a pH of 5.75. Presence of either SO42- or Cl- adversely affected the adsorption of fluoride in the order of SO42->Cl-. The FTIR studies of fluoride loaded adsorbent showed that partly the adsorption on the surface took place at surface hydroxyl sites. Mössbauer studies indicated that the overall absorption had gone down after fluoride adsorption that implies it has reduced the crystalline bond strength. The relative absorption area of ferrihydrite was marginally increased from 14 to 17%.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Chemical and Mathematical Science|
|Copyright:||© 2010 Elsevier B.V.|
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