Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates

Wolf, Stephan E.; Müller, Lars Peter; Barrea, Raúl A.; Kampf, Christopher J.; Leiterer, Jork; Panne, Ulrich; Hoffmann, Thorsten; Emmerling, Franziska; Tremel, Wolfgang

doi:10.1039/c0nr00761g

Cited by 120 publications

(127 citation statements)

References 59 publications

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“…They describe a non-classical nucleation mechanism through the existence of stable prenucleation clusters in subsaturated calcium carbonate solutions. Such clusters are discussed by Raiteri and Gale [24], Gebauer and Cölfen [25], and were experimentally verified by ultracentrifuge experiments, cryo-TEM and mass spectrometry [23][24][25][26]. It has been found that they remain hydrated [24].…”

Section: Magnetic Water Treatmentmentioning

confidence: 79%

“…Whereas their structure has not been determined yet, molecular dynamics simulations [27] describe them as disordered, hydrated flexible ionic polymers or DOLLOPs (dynamically ordered liquid like oxyanion polymers). They can aggregate into larger particles (up to about 100 nm) and form a liquid emulsion [26]. Coey [21] describes how a magnetic field gradient can act on the DOLLOPs, which could account for the so-called "magnetic memory" of water.…”

Section: Magnetic Water Treatmentmentioning

confidence: 99%

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Strong Gradients in Weak Magnetic Fields Induce DOLLOP Formation in Tap Water

Sammer¹,

Kamp²,

Paulitsch-Fuchs³

et al. 2016

Water

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Abstract:In 2012 Coey proposed a theory on the mechanism of magnetic water treatment based on the gradient of the applied field rather than its absolute strength. We tested this theory by measuring the effect of very weak field magnets (ď 10 G) containing strong magnetic inhomogeneities (∆B = 2 kG¨m´1) on tap water samples by the use of electric impedance spectroscopy (EIS) and laser scattering. Our results show an increased formation of nm-sized prenucleation clusters (dynamically ordered liquid like oxyanion polymers or "DOLLOPs") due to the exposure to the magnetic field and thus are consistent with Coey's theory which is therefore also applicable to very weak magnetic fields as long as they contain strong gradients.

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Section: Magnetic Water Treatmentmentioning

confidence: 79%

Section: Magnetic Water Treatmentmentioning

confidence: 99%

Strong Gradients in Weak Magnetic Fields Induce DOLLOP Formation in Tap Water

Sammer¹,

Kamp²,

Paulitsch-Fuchs³

et al. 2016

Water

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“…6 These not only provide the opportunity to perform hundreds of experiments very quickly, but the small reaction volume is such that the majority of droplets do not contain impurities; those that do generate outlying data points and can in principle be excluded. To this end, levitated droplets 7,8 and droplets created using automated dispensing systems 9-11 have previously been used to study homogeneous nucleation and to facilitate rapid screening of crystallisation conditions. Arrays of picolitre droplets formed on patterned self-assembled monolayers (SAMs) in contrast have provided an opportunity to study heterogeneous nucleation in confined volumes.…”

Section: Introductionmentioning

confidence: 99%

Calcium carbonate polymorph control using droplet-based microfluidics

2012

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Calcium carbonate (CaCO 3 ) is one of the most abundant minerals and of high importance in many areas of science including global CO 2 exchange, industrial water treatment energy storage, and the formation of shells and skeletons. Industrially, calcium carbonate is also used in the production of cement, glasses, paints, plastics, rubbers, ceramics, and steel, as well as being a key material in oil refining and iron ore purification. CaCO 3 displays a complex polymorphic behaviour which, despite numerous experiments, remains poorly characterised. In this paper, we report the use of a segmented-flow microfluidic reactor for the controlled precipitation of calcium carbonate and compare the resulting crystal properties with those obtained using both continuous flow microfluidic reactors and conventional bulk methods. Through combination of equal volumes of equimolar aqueous solutions of calcium chloride and sodium carbonate on the picoliter scale, it was possible to achieve excellent definition of both crystal size and size distribution. Furthermore, highly reproducible control over crystal polymorph could be realised, such that pure calcite, pure vaterite, or a mixture of calcite and vaterite could be precipitated depending on the reaction conditions and dropletvolumes employed. In contrast, the crystals precipitated in the continuous flow and bulk systems comprised of a mixture of calcite and vaterite and exhibited a broad distribution of sizes for all reaction conditions investigated.

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“…The LACC develops from pure, neutral, and saturated calcium bicarbonate solution crystallizing homogeneously in acoustic levitation [20]. These characteristic intermediates behave like a classical emulsion and are stabilized electrostatically [31]. Extended studies with additives resulted in destabilization phenomenon of LACC precursor using lysozyme, whereas the glycoprotein ovalbumin stabilizes this transient state, which carries a negative surface charge, and prevents undirected mineralization of the eggshell [32].…”

Section: Introductionmentioning

confidence: 99%

“…Our group pioneered a few years ago with the first time resolved in situ XRD experiments providing a continuous set of XRD patterns during a crystallization process [17,18,30]. In one of the early experiments, the non-classical crystallization pathway of calcium carbonate system involving a liquid/liquid phase separation and an emulsified of a highly hydrated liquid amorphous calcium carbonate (LACC) was investigated [20,31]. The LACC develops from pure, neutral, and saturated calcium bicarbonate solution crystallizing homogeneously in acoustic levitation [20].…”

Section: Introductionmentioning

confidence: 99%

Control of organic polymorph formation: crystallization pathways in acoustically levitated droplets

Nguyen

Roessler

Rademann

et al. 2016

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract:Theoretical and experimental studies indicate that crystal nucleation can take more complex pathways than expected on the ground of the classical nucleation theory. Among these pathways are the formation of prenucleation clusters and amorphous precursor phases. A direct in situ observation of the different pathways of nucleation from solution is challenging since the paths can be influenced by heterogeneous nucleation sites, such as container walls. Here, we provide insights into the crystallization process using the in situ combination of an acoustic levitator, Raman spectroscopy, and X-ray scattering. The contactless sample holder enables the observation of homogeneous crystallization processes and the detection of intermediates and final crystalline forms. We provide evidence for the existence of multiple pathways of nucleation based on the investigation of the crystallization of organic molecules from different solvents. Starting from a diluted solution, a supersaturation is reached during the experiment due to the evaporation of the solvent. The highly supersaturated solution reveals different pathways of crystallization. Depending on the degree of supersaturation either the thermodynamically stable or the metastable crystal form is observed.

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Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates

Cited by 120 publications

References 59 publications

Strong Gradients in Weak Magnetic Fields Induce DOLLOP Formation in Tap Water

Strong Gradients in Weak Magnetic Fields Induce DOLLOP Formation in Tap Water

Calcium carbonate polymorph control using droplet-based microfluidics

Control of organic polymorph formation: crystallization pathways in acoustically levitated droplets

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