Fluoride Adsorption on Goethite in Relation to Different Types of Surface Sites

Hiemstra, Tjisse; Riemsdijk, W.H. van

doi:10.1006/jcis.1999.6697

Cited by 131 publications

(107 citation statements)

References 41 publications

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“…Attempts to determine the site density of singly-coordinated surface groups of goethite with the fluoride ion showed that at high concentrations doubly-coordinated surface groups might also be involved (Hiemstra and Van Riemsdijk, 2000). The use of protons to derive the site density of the proton reactive surface groups is also questionable.…”

Section: à2mentioning

confidence: 99%

A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density

Hiemstra

Riemsdijk

2009

Geochimica et Cosmochimica Acta

237

216

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Section: à2mentioning

confidence: 99%

A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density

Hiemstra

Riemsdijk

2009

Geochimica et Cosmochimica Acta

237

216

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“…This is a common phenomenon with iron based adsorbents, which has also been reported by Wang and Reardon 15) and Hiemstra and van Riemsdijk. 16) At low pH, the active sites, being positively charged, have a strong binding power for anionic ligands through the formation of inner sphere complexes. In this section, Cr(VI) adsorption results at pH 4.2 are presented in the form of equilibrium isotherms as shown in Fig.…”

Section: Adsorption Equilibriummentioning

confidence: 99%

Magnetic Fixed-bed Column for Cr(VI) Removal from Aqueous Solution Using Schwertmannite

et al. 2008

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The fine particles of schwertmannite as an iron oxyhydroxide adsorbent has been suggested as a novel and strong Cr(VI) sorbent for treatment of Cr-contaminated industrial wastewater. The removal process was conducted in both batch and continuous trials. As a result of the batch experiments, the maximal adsorption capacity of the schwertmannite was obtained as 178 mg/g which was quite high amount in comparison with the usual applied Cr(VI) sorbents in the literatures. The continuous removal process involved a combination of a fixed bed column with a high gradient magnetic field which was firstly introduced as a novel designation of a fixed bed column to overcome the difficulties accompanied with the application of some especial fine particle adsorbents through the fixed-beds. The experimental results revealed that the magnetization force had a great function in this process to control the shape and the fitness of the bed during the sorption test as well as to simplify the experimental set-up.KEY WORDS: magnetic fixed bed column; Cr removal; high magnetic field; schwertmannite; wastewater treatment; electromagnetic processing of materials.tion, however, has some inherent limitations to be utilized as a continuous filtering system because of time-dependent plugging and saturation of its matrix.The most optimal configuration for continuous-flow sorption is the packed-bed column which gets gradually saturated from the feed to the solution exit end. High-quality fixed-bed column hardware is the subject of several US patents. In our study work, the experimental trials of the process have been conducted for many times by directly packing the column with the fine particle size of schwertmannite as the most strong Cr adsorbents. Extremely fine particles and mud like properties of the adsorbent, however, has caused a verity of problems to the system such as high pressure drop, mass transfer resistance and so on. To solve the problems dealing with the system, a magnetic fixed-bed column, as a novel designation of the fixed-bed columns, has been presented in this study. Moreover, the batch Cr(VI) adsorption data containing equilibrium models using the schwertmannite adsorbent and also the effect of pH on the adsorption to predict the sorption characteristics of the adsorbent have been given. Materials and MethodsAll chemicals used were of high purity and analytical grades. The schwertmannite powder as the chemical adsorbent of Cr(VI) in these experiments was made by homogenous hydrolysis of iron ferric salt (Fe 2 (SO 4 ) 3 · nH 2 O) according to the methods mentioned in our pervious work. 14)Stock solution of 130 mg/L of Cr(VI) for use in the fixed column experiment was prepared by dissolving of a known amount of K 2 Cr 2 O 7 in dionized water. In the batch mode adsorption trials, 50 mL of the solution with desired concentrations of Cr and the adsorbent were mixed in a bottle of 100 mL and shaken for about 5 h to reach to the equilibrium state. Then the yielded solution was filtered through a paper filter and then chromium c...

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“…11,19 Ligand exchange between surface hydroxyl group and F is also the predominate F adsorption mechanism. 17,20 Nevertheless, limited knowledge is available about the local coordination environment of As(V) surface complexes in the presence of F. The lack of this crucial information may inhibit the design of effective adsorbent for As(V) and F simultaneous removal.…”

Section: ■ Introductionmentioning

confidence: 99%

Fabrication, Characterization, and Application of a Composite Adsorbent for Simultaneous Removal of Arsenic and Fluoride

Jing

Cui

Hao

et al. 2012

ACS Appl. Mater. Interfaces

105

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Coexisting arsenic (As) and fluoride (F) in groundwater poses severe health risks worldwide. Highly efficient simultaneous removal of As and F is therefore of great urgency and high priority. The purpose of this study was to fabricate a novel composite adsorbent and explore the mechanism for concurrent removal of As(V) and F at the molecular level. This bifunctional adsorbent with titanium and lanthanum oxides impregnated on granular activated carbon (TLAC) exhibits a pronounced As(V) and F adsorption capacity over commercially available iron-and aluminumbased adsorbents for synthetic and real contaminated groundwater samples. Synchrotron-based X-ray microfluorescence analysis demonstrates that La and Ti were homogeneously distributed on TLAC. Extended X-ray absorption fine structure spectroscopic results suggest that As(V) formed bidentate binuclear surface complex as evidenced by an averaged Ti−As bond distance of 3.34 Å in the presence of F. Adsorption tests and Fourier transform infrared spectroscopy analysis indicate that F was selectively adsorbed on lanthanum oxides. The surface configurations constrained with the spectroscopic results were formulated in the charge distribution multisite complexation model to describe the competitive adsorption behaviors of As(V) and F. The results of this study indicate that TLAC could be used as an effective adsorbent for simultaneous removal of As(V) and F.

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Fluoride Adsorption on Goethite in Relation to Different Types of Surface Sites

Cited by 131 publications

References 41 publications

A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density

A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density

Magnetic Fixed-bed Column for Cr(VI) Removal from Aqueous Solution Using Schwertmannite

Fabrication, Characterization, and Application of a Composite Adsorbent for Simultaneous Removal of Arsenic and Fluoride

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