Preparation of micro-calcite powder using fine-bubble assisted carbonation as toothpaste material

Abstract

ABSTRACT

Introduction: Calcite (CaCO₃) is typically used in commercial toothpaste with particle size ranges from 1-12 μm. In the latest study, calcite was synthesized by using Ca(OH)₂ precursor from natural resources However, the resulting particle size does not match the size of the toothpaste filler. This study aims to prepare micro-calcite via fine-bubble assisted carbonation as toothpaste material. Methods: The calcite powder was prepared from Ca(OH)₂ analytical grade powder utilizing the fine-bubble carbonation process with the Ca(OH)₂ concentration and initial pH variation. The study was started by making a Ca(OH)₂ suspension with a concentration of 0.25, 0.5, 0.75, 1 and 1.25 M using 2.000 ml methanol as a solvent. 0.5 M NaH₂PO₄ solutions were utilized to adjust the initial pH of 0.5 M Ca(OH)₂ suspension into 8, 9, and 10. The suspensions were aerated using CO₂ fine-bubble for two hours to produce CaCO₃ samples. All precipitated CaCO₃ particles were characterized by PSA, Zeta-Potential, and FTIR measurements. Results: The calcite phase was identified from the FTIR transmittance. Aragonite or vaterite phase was not observed in the samples. PSA result shows the size of CaCO₃ particles from samples 0.25 M to 1.25 M are as follows 3.03, 3.23, 2.79, 3.70, 0.99 μm respectively. Meanwhile, the particle sizes of CaCO₃ in samples with a pH of 8, 9 and 10 are 3.00, 2.03 and 2.50 μm respectively. The zeta potential shows the value ranges from -23.2 mV to -11.9 mV, indicating fair dispersion ability. Conclusion: The fine bubble assisted carbonation method in this study helps in producing calcite in micron size that could be used as alternative fillers for toothpaste.

Keywords: calcite, fine-bubble, carbonation, particle size, toothpaste