Fluorine Compounds, Inorganic

Aigueperse, Jean; Mollard, P.; Devilliers, Didier; Chemla, M.; Faron, R.; Romano, René; Cuer, Jean Pierre

doi:10.1002/14356007.a11_307

Cited by 50 publications

(43 citation statements)

References 118 publications

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“…The disappearance of the peak at δ F = −127.9 ppm for SiF 6 2− could be due to the reaction of SiF 6 2− + NaOH → NaF + SiO 2 + H 2 O (used in water fluoridation). 37 However, the huge upfield shift close to the unbound fluoride (δ F = −122.3 ppm) could be the result of the decomplexation of fluoride at higher pH (~ 7.0), as expected.…”

supporting

confidence: 54%

A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H₂O)]₄^4– in a Molecular Box

et al. 2012

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We present an unprecedented fluoride-water cyclic cluster of [F(H2O)]44− assembled in a cuboid-shaped molecular box formed by two large macrocycles. Structural characterization reveals that the [F(H2O)]44− is assembled by strong H-bonding interactions [OH···F = 2.684(3) to 2.724(3) Å], where a fluoride anion plays the topological role of a water molecule in the classical cyclic water octamer. The interaction of fluoride was further confirmed by 19F NMR and 1H NMR spectroscopies, indicating the encapsulation of the anionic species within the cavity in solution. High level DFT calculations and Bader topological analyses fully support the crystallographic results, demonstrating that the bonding arrangement in the fluoride-water cluster arises from the unique geometry of the host.

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supporting

confidence: 54%

A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H₂O)]₄^4– in a Molecular Box

et al. 2012

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“…However, it was recently demonstrated that during the solubilization process, PSMs become exposed to various chemical elements released from the RP (7). Released fluoride (F Ϫ ) was observed to cause a strong decrease in P solubilization, suggesting that most of the microbial RP solubilization systems may operate at suboptimal conditions (7), given that fluorine is a ubiquitous element in RPs (8). Thus, it is expected that strategies to remove F Ϫ while it is released from RPs could increase the overall efficiency of RP solubilization.…”

mentioning

confidence: 99%

Biochar Enhances Aspergillus niger Rock Phosphate Solubilization by Increasing Organic Acid Production and Alleviating Fluoride Toxicity

Mendes

Zafra

Vassilev

et al. 2014

Appl Environ Microbiol

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e During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F ؊ ) is released together with phosphorus (P), strongly inhibiting the process. In the present study, the effect of two F ؊ adsorbents [activated alumina (Al 2 O 3 ) and biochar] on RP solubilization by Aspergillus niger was examined. Al 2 O 3 adsorbed part of the F ؊ released but also adsorbed soluble P, which makes it inappropriate for microbial RP solubilization systems. In contrast, biochar adsorbed only F ؊ while enhancing phosphate solubilization 3-fold, leading to the accumulation of up to 160 mg of P per liter. By comparing the values of F ؊ measured in solution at the end of incubation and those from a predictive model, it was estimated that up to 19 mg of F ؊ per liter can be removed from solution by biochar when added at 3 g liter ؊1 to the culture medium. Thus, biochar acted as an F ؊ sink during RP solubilization and led to an F ؊ concentration in solution that was less inhibitory to the process. In the presence of biochar, A. niger produced larger amounts of citric, gluconic, and oxalic acids, whether RP was present or not. Our results show that biochar enhances RP solubilization through two interrelated processes: partial removal of the released F ؊ and increased organic acid production. Given the importance of organic acids for P solubilization and that most of the RPs contain high concentrations of F ؊ , the proposed solubilization system offers an important technological improvement for the microbial production of soluble P fertilizers from RP.

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“…During the 1990s, the demand for fluorspar decreased (briefly) thanks to the international phaseout of CFCs. CFC substitutes, though, Table 2 Usage of fluorspar in thousand tonnes in the United States for 1960, 1980(Davenport 1979and Miller 2003 notably hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs), are responsible for increasing hydrofluoric acid consumption in more recent years (Aigueperse 2000). Table 2 shows the consumption of fluorspar in the United States in 1960States in , 1980States in , and 2003 by application.…”

Section: Consumption and Usesmentioning

confidence: 99%

Accounting for Fluorine: Production, Use, and Loss

Villalba

Ayres

Schrøder³

2007

J of Industrial Ecology

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Summary Fluorine is an essential element to human health and to the chemical industry. In spite of our dependence on fluorine and fluorine compounds, we have yet to learn to use them wisely. Our fluorine history, which spans about a hundred years, has had negative effects such as hydrofluoric acid pollution caused by aluminum smelters and ozone depletion due to chlorofluorocarbon (CFC) emissions. More recent concerns center on greenhouse effects from CFCs, hydrofluorocarbons (HFCs), and sulfur hexafluoride (SF6). In this article we note also that fluorine is a nonrenewable resource that is nonsubstitutable for many purposes. This article tracks fluorine from sources through conversion processes to end uses, most of which are dissipative. We present a stock‐flow model of the fluorine system. Based on this model we consider some possible measures that could be taken to increase the degree of recovery. To mention one example, a large percentage of the world demand for fluorspar could be supplied by the phosphate rock (fertilizer) industry, which currently dissipates a great deal of recoverable fluorine in waste phospho‐gypsum.

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Fluorine Compounds, Inorganic

Cited by 50 publications

References 118 publications

A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H₂O)]₄^4– in a Molecular Box

A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H₂O)]₄^4– in a Molecular Box

Biochar Enhances Aspergillus niger Rock Phosphate Solubilization by Increasing Organic Acid Production and Alleviating Fluoride Toxicity

Accounting for Fluorine: Production, Use, and Loss

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Fluorine Compounds, Inorganic

Cited by 50 publications

References 118 publications

A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H2O)]44– in a Molecular Box

A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H2O)]44– in a Molecular Box

Biochar Enhances Aspergillus niger Rock Phosphate Solubilization by Increasing Organic Acid Production and Alleviating Fluoride Toxicity

Accounting for Fluorine: Production, Use, and Loss

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A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H₂O)]₄^4– in a Molecular Box

A Self-Assembled Fluoride–Water Cyclic Cluster of [F(H₂O)]₄^4– in a Molecular Box