Facile synthesis of vaterite fine powder CaCO3 from padalarang natural limestone with pH modifying via fine-bubble carbonation
Natural limestone, known for its high calcium carbonate (CaCO _3 ) content (∼95%) and safety in health applications, is widely used in science and industry. It exists in three forms: calcite, vaterite, and aragonite. Vaterite’s spherical structure, non-toxic nature, biocompatibility, and high porosi...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | Materials Research Express |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/2053-1591/add66d |
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| Summary: | Natural limestone, known for its high calcium carbonate (CaCO _3 ) content (∼95%) and safety in health applications, is widely used in science and industry. It exists in three forms: calcite, vaterite, and aragonite. Vaterite’s spherical structure, non-toxic nature, biocompatibility, and high porosity is particularly valuable for biomedical applications. However, its metastability makes it more challenging to synthesize consistently compared to calcite and aragonite. This study aimed to synthesize CaCO _3 from natural limestone from Padalarang, West Java, Indonesia, using a fine-bubble carbonation method, varying HCl concentrations to assess pH’s influence on vaterite formation. The method involved converting natural limestone to CaO then to Ca(OH) _2 as the primary carbonation precursor. Fine CO _2 bubbles were introduced into a Ca(OH) _2 solution (a mixture of 5% water and 95% methanol), with HCl concentrations of 0.02 M, 0.04 M, and 0.08 M added. The carbonation process was conducted at 300 rpm, 20 ± 3 °C, and a flow rate of 1 l min ^−1 for 2 h. The CaCO _3 powders were characterized using x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electronic microscopy (SEM), and a particle size analyzer (PSA). The XRD result indicated that a 0.04 M HCl concentration yielded the highest vaterite content (93%). SEM shows the spherical morphology of vaterite CaCO _3 both in 00.4 M and 0.08 M HCl concentrations, while FTIR confirmed the presence of calcite (712, 872, 1087 cm ^−1 ) and vaterite (744 cm ^−1 ). PSA showed that HCl concentration influenced particle size and the calcite-vaterite ratio, with Z-average particle sizes ranging from 114.8 nm to 118.2 nm. |
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| ISSN: | 2053-1591 |