Fluoride Adsorption Onto Granular Ferric Hydroxide: Effects of Ionic Strength, PH, Surface Loading, and Major Co-Existing Anions

Abstract

Fluoride adsorption onto granular ferric hydroxide (GFH) was investigated using batch methods, under various ionic strength, pH, surface loading, and major co-existing anion conditions. Adsorption of fluoride on GFH included an initial fast adsorption phase followed by a slow adsorption phase. within the pH range of 2-11, fluoride adsorption equilibrium was not affected by ionic strength, but was significantly affected by pH. Maximum adsorption was achieved in the pH range of 3-6.5. under the same pH condition, fluoride adsorption followed the Freundlich isotherm, indicating that the GFH surface was heterogeneous. X-ray photoelectron spectroscopy (XPS) and attenuated total reflection-infrared (ATR-IR) spectroscopy data showed evidence for fluoride sorption on the GFH surface via inner-sphere complexation accompanying increased hydrogen bonding and surface hydroxylation. Major anions, including phosphate, bicarbonate, sulfate, and chloride, reduced fluoride adsorption in the following order: H2PO4- > HCO3- > SO42- > Cl-.

Department(s)

Civil, Architectural and Environmental Engineering

Second Department

Chemistry

Sponsor(s)

China Scholarship Council
Missouri University of Science and Technology. Environmental Research Center
University of Missouri Research Board

Keywords and Phrases

XPS; Granular Ferric Hydroxide; Ionic Strength; pH; Adsorption; Fluorides; X-ray photoelectron spectroscopy

International Standard Serial Number (ISSN)

0304-3894

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2009 Elsevier, All rights reserved.

Publication Date

01 Nov 2009

Link to Full Text

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