Precipitated Calcium Carbonate Synthesis by Simultaneous Injection to Produce Nano Whisker Aragonite

Abstract

The synthesis of pure calcium carbonate nanocrystals was achieved using a simultaneous injection method to produce nano particles of uniform size. These were characterized using scanning electron microscopy and powder X-ray diffraction. The nano particles were needle-shaped aragonite polymorphs, approximately 100-200 nm in length. The aragonite polymorph of calcium carbonate was prepared using aqueous solutions of CaCl 2 and Na 2 CO 3 , which were injected simultaneously into double distilled water at 50°C and then allowed to react for 1.5 h. The resulting whisker-type nano aragonite with high aspect ratio (30) is biocompatible and potentially suitable for applications in light weight plastics, as well as in the medical, pharmaceutical, cosmetic and paint industries.

Calcium Carbonate Precipitation for CO2 Storage and Utilization: A Review of the Carbonate Crystallization and Polymorphism

“…Recently, Ramakrishna et al (2016) observed the formation of polymorphs according to the temperature, reaction time, and pH using 0.1 M CaCl2 and 0.1 M Na2CO3 solutions at 25 to 50°C and at pH 10-12. They reported that pH 10 is the most suitable condition for obtaining pure aragonite, whereas calcite became the dominant polymorph when pH exceeded 10.…”

Lab‐scale atmospheric CO2 absorption for calcium carbonate precipitation in sand

“…40-42 2. High pH conditions, greater than pH 11, are favorable for calcite formation, [40][41][42][43] hence carbonate solution produced through DAC with a pH of 13.9 is favorable. 3.…”

“…In view of the intended use of carbonate ion capture through DAC for CaCO 3 precipitation for ground improvement, the precipitation condition would be at an ambient condition of 1 atm and 20°C (300 K). Literature assessing calcite precipitation potential under these synthesis conditions has concluded the following: Synthesis temperature around 20–25°C is favorable for calcite formation High pH conditions, greater than pH 11, are favorable for calcite formation, hence carbonate solution produced through DAC with a pH of 13.9 is favorable. Potassium hydroxide ionic strength is lower than that of sodium or other metals, hence promoting calcite yield …”

“…Literature assessing calcite precipitation potential under these synthesis conditions has concluded the following: Synthesis temperature around 20–25°C is favorable for calcite formation High pH conditions, greater than pH 11, are favorable for calcite formation, hence carbonate solution produced through DAC with a pH of 13.9 is favorable. Potassium hydroxide ionic strength is lower than that of sodium or other metals, hence promoting calcite yield Calcium source concentration at 0.08 M Ca(OH) 2 containing 0.08962 mol of Ca 2+ is favorable as high ionic concentrations increase the formation of CaCO 3 particles due to an increase in specific surface area for particles to grow …”

Influence of synthesis conditions on the calcium carbonate microparticle properties obtained by homogeneous and heterogeneous precipitation

“…Therefore, calcium carbonate of the required quality is more frequently obtained by chemical methods. Two of the most widespread methods to obtain CaCO 3 are the carbonization of natural dolomite or other calcium-containing raw materials (Chilakala et al 2016;Teir et al 2016) and the chemical precipitation by mixing soluble calcium salts (calcium chloride or nitrate) with sodium carbonate in an aqueous medium (heterogeneous precipitation) (Kawano et al 2009;Ramakrishna et al 2016;Prasetia et al 2017). The sources of calcium can be industrial wastes such as: concrete waste (Van der Zee and Zeman 2016), steel production wastes (Teir et al 2016;Said et al 2013;Mattila and Zevenhoven 2014), spent marble crumb (Erdogan and Eken 2017), soda production wastes (Mikhaylova et al 2004;Molchanov et al 2006), etc.…”