Removal of Arsenic from Water Using Granular Ferric Hydroxide: Macroscopic and Microscopic Studies
Removal of arsenate from water using granular ferric hydroxide (GFH) was investigated under different pH and As(V) loading conditions, using batch equilibrium adsorption, FTIR, and EXAFS methods. the arsenate adsorption envelopes on GFH exhibited broad adsorption maxima when the initial As(V) concentration was less than 500 mg/L at sorbent concentration of 10 g/L. as the initial As(V) concentration increased to 500, 1000 or 2000 mg/L for the same sorbent concentration, distinct adsorption maxima appeared and shifted to lower pH. Acidimetric-alkalimetric titration and arsenic adsorption isotherm data indicated that the surface of GFH is high heterogeneous. FTIR spectra revealed that complexes of two different structures, bidentate and monodentate, were formed upon the adsorption of arsenate on GFH, and bidentate complexes were only observed at pH values greater than 6. the EXAFS analyses confirmed that arsenate form bidentate binuclear complexes with GFH at pH 7.4 as evidenced by an average Fe-As(V) bond distance of 3.32 Å.
J. Wang et al., "Removal of Arsenic from Water Using Granular Ferric Hydroxide: Macroscopic and Microscopic Studies," Journal of Hazardous Materials, Elsevier, Jan 2007.
The definitive version is available at http://dx.doi.org/10.1016/j.jhazmat.2007.12.012
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Adsorption; Arsenic; EXAFS; FTIR; Granular Ferric Hydroxide; Water
Article - Journal
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