Polymorph control of calcium carbonate by reactive crystallization using microbubble technique

Matsumoto, Masakazu; Fukunaga, Tetsuo; Onoe, Kaoru

doi:10.1016/j.cherd.2010.02.007

Cited by 64 publications

(44 citation statements)

References 16 publications

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“…Compared to the previous studies, our experimental results indicated that not only increasing V MeOH but also bubble injection and minimizing bubble size led to the enhanced production of unstable ß-form caused by the inhibition of polymorphic transformation from ß-form to α-form. Investigation about the electric charge on the minutebubble surface to clarify the occurrence of interactions at the gas-liquid interfaces revealed that the zeta potential of minute-bubbles with d bbl of 10 -30 µm was negative value between -50 and -100 mV [6,7,9], and the presence of glycine and methanol led to the zeta potential approach to 0 mV [12]. These findings indicated that glycine and methanol concentrations increased locally in the vicinity area of minute gas-liquid interfaces.…”

Section: Comparison Of Antisolvent Crystallization Of Glycine Polymorphsmentioning

confidence: 99%

“…While mixing methanol with the saturated glycine solution, N 2 bubbles with different values of the average bubble diameter (d bbl ) were continuously supplied to 300 ml of the mixed solution and glycine was crystallized. Minute-bubbles with a d bbl of 10 µm were generated using a self-supporting bubble generator by increasing the impeller shear rate under reduced pressure [7,9], with the rotation rate maintained at 1500 min -1 and the N 2 flow rate (F N2 ) controlled at 7.35 mmol/(l•min). Bubbles with a d bbl of 600, 900, or 2000 µm were obtained using a dispersing-type generator, and d bbl was varied by changing the hole size (65 -300 µm) on the dispersing plate at the same F N2 mentioned above.…”

Section: Production Of Glycine Polymorphs By Antisolvent Crystallizatmentioning

confidence: 99%

“…Minimizing bubble diameter in gas-liquid systems helps achieve the following: i) acceleration of mass transfer and reactive absorption with an increase in the gas-liquid interfacial area, ii) increase in the average residence time of the bubbles with a decrease in buoyancy, and iii) occurrence of interactions at the gas-liquid interface caused by electrification of minute-bubbles [6,7]. Because solute and antisolvent are accumulated near the gas-liquid interfaces by the residence of minute-bubbles with surface potential in the liquid phase for a long period of time, the production of a less stable polymorph and the shift in the overall solid-liquid equilibrium can be expected to occur.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Enhanced production of unstable polymorph by antisolvent crystallization supplying minute-bubbles

Matsumoto

Wada

Onoe

2013

MATEC Web of Conferences

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Section: Comparison Of Antisolvent Crystallization Of Glycine Polymorphsmentioning

confidence: 99%

Section: Production Of Glycine Polymorphs By Antisolvent Crystallizatmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Enhanced production of unstable polymorph by antisolvent crystallization supplying minute-bubbles

Matsumoto

Wada

Onoe

2013

MATEC Web of Conferences

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“…18,20) Most research on the in-situ formation process has focused on the synthesis of calcite in the pulp slurry. 1820) Because the characteristics of calcium carbonate are affected by its morphology, 13,15,21) controlling the structure and morphology of calcium carbonate is an important research subject.…”

Section: 16)mentioning

confidence: 99%

Improving Recycled Fiber by Applying <i>In-Situ</i> Aragonite Calcium Carbonate Formation Process

et al. 2014

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Needle-shaped aragonite, a thermodynamically metastable polymorph of CaCO 3 , was synthesized in a deinked old newspaper pulp (ONP) slurry, otherwise known as the in-situ aragonite formation process, in order to improve the optical properties such as the brightness and ERIC value (effective residual ink concentration) as well as to preserve the strength properties such as the breaking length of the resultant handsheet. The brightness and ERIC value of the handsheet obtained from pulp that was subjected to the in-situ aragonite formation process was improved by 20.4% (from 56.8 to 68.4%) and 55.4% (from 292.1 to 130.4 ppm), respectively, relative to a raw ONP sample. The effects of the in-situ aragonite formation process on the resultant handsheet were compared with the results obtained from a similar process in which rhombohedraltype calcite was synthesized instead of the needle-shaped aragonite. From the comparison, it can be concluded that the in-situ aragonite formation process provides better optical and strength properties to the resultant handsheet than that of calcite, and this is attributed to the needleshaped morphology of aragonite.

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“…Crystals of CaCO 3 can be divided into three types: calcite, vaterite, and aragonite. The majority of the CaCO 3 produced in concrete may be considered to be calcite: Ca(OH) 2 is first generated among the hardened bodies of cement, which then combines with CO 3 2− ions in water in the pores to form CaCO 3 in the form of calcite [24,25]. Meanwhile, vaterite is a hexagonal crystal, whose pore-filling effect is better than that of other CaCO 3 crystals because of its large volume [25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Control of the Polymorphism of Calcium Carbonate Produced by Self-Healing in the Cracked Part of Cementitious Materials

Choi

Inoue

et al. 2017

Applied Sciences

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Abstract:Cracking is an inherent development in reinforced concrete structures and can lead to serious damages during their service period. The repeated occurrence of such damages can enlarge the cracks, thereby allowing other deteriorating elements such as CO 2 and Cl − to further infiltrate the concrete, which can seriously compromise the concrete structure. This study focuses on the type of calcium carbonate (CaCO 3 ) crystals generated by the self-healing phenomenon. Owing to polymorphism, CaCO 3 has three types of crystal forms-calcite, vaterite, and aragonite-whose formation can be controlled by the temperature and pH. Vaterite has the highest density among these crystals, and it is expected to be capable of self-healing. Therefore, experiments were conducted to establish the conditions required to promote the generation of vaterite. A saturated Ca(OH) 2 solution with CO 2 nanobubbles (CN) was employed for effective self-healing. The temperature was controlled at 20, 40, and 60 • C, and the pH was controlled at 9.0, 10.5, and 12.0. The results showed that the self-healing of cracks occurred both on the surface and internally, and the main product of the self-healing phenomenon was vaterite in CaCO 3 crystals at a pH of 9.0 and a temperature of 40 • C. Furthermore, the addition of a saturated Ca(OH) 2 solution with CO 2 nanobubbles (CN) resulted in the most effective self-healing of the surface and internal cracks.

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Polymorph control of calcium carbonate by reactive crystallization using microbubble technique

Cited by 64 publications

References 16 publications

Enhanced production of unstable polymorph by antisolvent crystallization supplying minute-bubbles

Enhanced production of unstable polymorph by antisolvent crystallization supplying minute-bubbles

Improving Recycled Fiber by Applying <i>In-Situ</i> Aragonite Calcium Carbonate Formation Process

Control of the Polymorphism of Calcium Carbonate Produced by Self-Healing in the Cracked Part of Cementitious Materials

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