The influence of xanthan on the crystallization of calcium carbonate

Yang, Xiaodeng; Xu, Guiying

doi:10.1016/j.jcrysgro.2010.11.158

Cited by 45 publications

(18 citation statements)

References 44 publications

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“…On the other hand, the rosette-like aggregates are predominant calcite forms in both Ca-gels. This is in agreement with findings of some other authors that precipitated CaCO 3 in presence of alginate or xanthan, but at concentrations lower than critical for gel formation [45,47]. The predominant formation of rosette-like calcite was explained by its nucleation on a gelled microparticles template.…”

Section: Caco 3 Precipitation In Alginate Gelssupporting

confidence: 93%

Crystallization of Calcium Carbonate in Alginate and Xanthan Hydrogels

et al. 2017

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Calcium carbonate polymorphs were crystallized in alginate and xanthan hydrogels in which a degree of entanglement was altered by the polysaccharide concentration. Both hydrogels contain functional groups (COOH and OH) attached at diverse proportions on saccharide units. In all systems, the precipitation process was initiated simultaneously with gelation, by the fast mixing of the calcium and carbonate solutions, which contain the polysaccharide molecules at respective concentrations. The initial supersaturation was adjusted to be relatively high in order to ensure the conditions suitable for nucleation of all CaCO 3 polymorphs and amorphous phase(s). In the model systems (no polysaccharide), a mixture of calcite, vaterite and amorphous calcium carbonate initially precipitated, but after short time only calcite remained. In the presence of xanthan hydrogels, precipitation of either, calcite single crystals, porous polyhedral aggregates, or calcite/vaterite mixtures were observed after five days of ageing, because of different degrees of gel entanglement. At the highest xanthan concentrations applied, the vaterite content was significantly higher. In the alginate hydrogels, calcite microcrystalline aggregates, rosette-like and/or stuck-like monocrystals and vaterite/calcite mixtures precipitated as well. Time resolved crystallization experiments performed in alginate hydrogels indicated the initial formation of a mixture of calcite, vaterite and amorphous calcium carbonate, which transformed to calcite after 24 h of ageing.

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Section: Caco 3 Precipitation In Alginate Gelssupporting

confidence: 93%

Crystallization of Calcium Carbonate in Alginate and Xanthan Hydrogels

et al. 2017

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“…[40]. As shown in Figure 3a, the broad absorption peak at 3351 cm −1 indicated the existence of the stretching vibration of hydroxyl groups, while the absorption peak at 1724 cm −1 was attributed to the C=O stretching carbonyl ester of the acetate group [20,41,42]. The absorption peaks at 1626 and 1379 cm −1 were a result of the asymmetrical C=O stretching vibration of the succinate and acetate functional groups and symmetrical stretching vibration of the carboxylate -COO − group from acid residues, respectively [20,41].…”

Section: Attenuated Total Reflection-fourier Transform Infrared (Atr-mentioning

confidence: 99%

Preparation of Succinoglycan Hydrogel Coordinated With Fe3+ Ions for Controlled Drug Delivery

Jeong

Kim

et al. 2020

Polymers

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Hydrogel materials with a gel-sol conversion due to external environmental changes have potential applications in a wide range of fields, including controlled drug delivery. Succinoglycans are anionic extracellular polysaccharides produced by various bacteria, including Sinorhizobium species, which have diverse applications. In this study, the rheological analysis confirmed that succinoglycan produced by Sinorhizobium meliloti Rm 1021 binds weakly to various metal ions, including Fe2+ cations, to maintain a sol form, and binds strongly to Fe3+ cations to maintain a gel form. The Fe3+-coordinated succinoglycan (Fe3+-SG) hydrogel was analyzed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, circular dichroism (CD), and field-emission scanning electron microscopy (FE-SEM). Our results revealed that the Fe3+ cations that coordinated with succinoglycan were converted to Fe2+ by a reducing agent and visible light, promoting a gel-sol conversion. The Fe3+-SG hydrogel was then successfully used for controlled drug delivery based on gel-sol conversion in the presence of reducing agents and visible light. As succinoglycan is nontoxic, it is a potential material for controlled drug delivery.

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“…Crystallization of CaCO 3 received both scientific and industrial interest and has been widely studied for decades [1,2]. Generally, it exists in six different forms of which three are of anhydrous crystalline forms: calcite, aragonite, and vaterite and three of hydrated forms: amorphous CaCO 3 (ACC), calcium carbonate monohydrate (CaCO 3 H 2 O), and calcium carbonate hexahydrate (CaCO 3 6H 2 O) [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…The applications of CaCO 3 are strictly restricted to its crystalline properties such as chemical purity, specific surface area, particle size, and morphology [1,[6][7][8]. In recent past, synthesis of CaCO 3 has been intensively studied with the aim of understanding how crystal polymorph and structural features can be controlled by organic additives [9][10][11], due to its wide range of applications in paper-making, cosmetics, medicines, detergents, ceramics, rubber, paint, and batch precipitation [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Effect of NTA and temperature on crystal growth and phase transformations of CaCO3

Gopi

Kumaravel

Subramanian

2015

Desalination and Water Treatment

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A B S T R A C TPhase transition from vaterite to calcite is a general behavior of CaCO 3 materials. The effect of nitrilotriacetic acid disodium salt (NTA) on the crystallization behavior and polymorphism of CaCO 3 was studied at different temperatures between 60 and 230˚C. The morphologies and the structure of the precipitates were characterized using scanning electron microscope, field emission scanning electron microscopy, powder X-ray diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy. It was observed that NTA could change the morphologies and crystal structures of CaCO 3 with temperature and stabilize least stable vaterite at high temperature. An anomalous conversion of calcite to vaterite in the presence of NTA was observed. The effect of amount of NTA added on the crystallization behavior at selected temperatures is reported.

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The influence of xanthan on the crystallization of calcium carbonate

Cited by 45 publications

References 44 publications

Crystallization of Calcium Carbonate in Alginate and Xanthan Hydrogels

Crystallization of Calcium Carbonate in Alginate and Xanthan Hydrogels

Preparation of Succinoglycan Hydrogel Coordinated With Fe3+ Ions for Controlled Drug Delivery

Effect of NTA and temperature on crystal growth and phase transformations of CaCO3

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