The reaction of kaolin with fluorides: I. Effect of neutral and acid sodium fluoride solutions

Semmens, B.; Meggy, A. B.

doi:10.1002/jbt.2570160403

Cited by 7 publications

(6 citation statements)

References 8 publications

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“…5 ) and allophane (not shown here) are morphologically similar to curves found for Illinois soils. The apparent adsorption isotherm for kaolin is consistent with the dissolution of kaolinite by fluoride as a function of pH (Semmens and Meggy, 1966) 0.72X; -382.57X3 f 1.62X4 + 75.33X1 X j -0.09X1 X4 -0.03XZ X 4 . wherein fluoroaluminate and fluorosilicates are formed.…”

Section: Resultssupporting

confidence: 60%

Fluoride Adsorption by Illinois Soils

Omueti

Jones

1977

Journal of Soil Science

105

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ourteen surface and 6 subsurface horizons of' Illinois soils adsorbed significant amounts of 1;-with release of OH -. At low concentrations, adsorption was described by both Langmuir and Freundlich isotherms. The calculated Langmuir adsorption capacities were related to pH, clay, organic carbon, and amorphous aluminum contents.Two soils with different gross chemical properties behaved in essentially the same manner, with adsorption maxima occuring between pH 5.5 and 6.5. The similarity between adsorption at different pH values for the soils and those for bauxite, allophane and synthesized 'soil chlorite', and the lack of adsorption maxima between pH 5.5 and 6.5 for pure kaolinite and montmorillonite, suggest that F -adsorption in the soils is due primarily t o the presence of amorphous aluminum oxyhydroxides which are common weathering products in these soils.

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Section: Resultssupporting

confidence: 60%

Fluoride Adsorption by Illinois Soils

Omueti

Jones

1977

Journal of Soil Science

105

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“…They indicated that F forms Al and Fe complexes which disrupt the mineral surfaces. Similar studies on soils and soil minerals have been conducted by Semmens and Meggy (1966), Perrott et al (1976), and Omueti and Jones (1977).…”

Section: Introductionmentioning

confidence: 58%

Effect of fluoride and phosphate on yield and mineral composition of barley grown on three soils

Elrashidi

Persaud

Baligar

1998

Communications in Soil Science and Plant Analysis

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In a greenhouse experiment, the effect of fluoride (F) and phosphorus (P) addition on the growth and mineral composition of barley (Hordeum vulgare L.) was studied in three different soils, Cahaba sandy loam (acid), Weld loam (neutral), and Haverson silty loam (alkaline calcareous). Four levels of F [0, 100, 400, and 1,000 mg kg -1 soil as hydrogen fluoride (HF)] and three levels of P [50, 150, and 550 mg kg -1 soil as phosphoric acid (H 3 PO 4 )] were used.

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“…Romo [8], Kau [9], and Weerasooriya [10] attributed the release of OH -to the exchange between F -and OH in the lattice of clay minerals. Semmens [11] and He [12] concluded that the reaction of clay minerals with F -led to the destruction of crystal structures and the formation of cryolite. Bower and Hatcher [13] considered the adsorption mechanism at low F -concentration as the exchange between F -and OH in Al(OH) 3 or polymeric aluminum rather than in the lattice of clay minerals.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of fluoride on clay minerals and their mechanisms using X-ray photoelectron spectroscopy

Xiao

et al. 2010

Front. Environ. Sci. Eng. China

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This research investigates the adsorption mechanisms of fluoride (F) on four clay minerals (kaolinite, montmorillonite, chlorite, and illite) under different F -concentrations and reaction times by probing their fluoride superficial layer binding energies and element compositions using X-ray photoelectron spectroscopy (XPS). At high F -concentrations (C 0 = 5-1000 mg$L -1 ), the amount of F -adsorbed (Q F ), amount of hydroxide released by clay minerals, solution F -concentration, and the pH increase with increasing C 0 . The increases are remarkable at C 0 > 50 mg$L -1 . The Q F increases significantly by continuously modifying the pH level. At C 0 < 5-100 mg$L -1 , clay minerals adsorb H + to protonate aluminum-bound surface-active hydroxyl sites in the superficial layers and induce F -binding. As the C 0 increases, F -, along with other cations, is adsorbed to form a quasi-cryolite structure. At C 0 > 100 mg$L -1 , new minerals precipitate and the product depends on the critical Al 3+ concentration. At [Al 3+ ] > 10 -11.94 mol$L -1 , cryolite forms, while at [Al 3+ ] < 10 -11.94 mol$L -1 , AlF 3 is formed. At low C 0 (0.3-1.5 mg$L -1 ), proton transfer occurs, and the F -adsorption capabilities of the clay minerals increase with time.

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The reaction of kaolin with fluorides: I. Effect of neutral and acid sodium fluoride solutions

Cited by 7 publications

References 8 publications

Fluoride Adsorption by Illinois Soils

Fluoride Adsorption by Illinois Soils

Effect of fluoride and phosphate on yield and mineral composition of barley grown on three soils

Adsorption of fluoride on clay minerals and their mechanisms using X-ray photoelectron spectroscopy

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