Synthesis Of Calcium Carbonate Research Articles

Biomimetic synthesis of calcium carbonate under phenylalanine: Control of polymorph and morphology.

In biomineralization, organisms have the abilities to produce biominerals with superior properties. One of the most attractive features of biominerals is the presence of the proteins consisting of different contents of amino acids in crystals. In the present work, L-phenylalanine (Phe) was used as an additive for the controllable crystallization of calcium carbonate (CaCO3). The obtained CaCO3 crystals were characterized by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), elemental analysis and high-resolution transmission electron microscopy (HRTEM). The experimental results suggest that single calcite crystals are formed at low Phe concentrations. High concentrations of Phe inhibit the nucleation and growth of calcite, and promote the formation of vaterite crystals with solid or hollow structures. The morphology and crystal form of CaCO3 are also significantly affected by the flow rate of CO2. After that, a possible mechanism (competition mechanism) action of Phe in the formation of CaCO3 is proposed. Finally, the effects of temperature on the formation of vaterite were determined to explore the growth mechanism of hexagonal vaterite. The work of controlling the preparation of CaCO3 crystals in the presence of Phe will help us to imitate and learn nature, and bring new insights into understanding bionics. Meanwhile, it provides a new method for the synthesis of CaCO3 biomaterials with different crystal forms and morphologies.

Synthesis of Calcium Carbonate in the Presence of Bile, Albumen, and Amino Acids

The thermodynamic and experimental modeling of calcium carbonate crystallization in a model solution of human bile is performed. CaCO3 samples are synthesized in the presence of additives with variable additive concentrations. The phase and group-structure composition of the synthesized samples is determined by X-ray powder diffraction (XRD), Fourier-transform IR spectroscopy, and optical microscopy. Amorphous calcium carbonate and calcite are found to be primarily formed in the human bile model solution in the presence of glycine, glutamic acid, and albumen separately. When twenty amino acids and albumen are present in the highest concentrations permissible in the human body, vaterite is formed as the major phase. Distinctions in phase and group-structure compositions of samples are shown to occur depending on synthetic parameters. An effect is suggested to be caused by the compositions and concentrations of the additives used on the formation of a certain calcium carbonate polymorph.

Synthesis of highly dispersed calcium carbonate at excessive pressure of carbon dioxide

The purpose of the paper was to find out how the conditions for the synthesis of calcium carbonate, having the patent of the Russian Federation No. 2489355, affect the average particle size and their size distribution. The process was carried out in a transparent 1 liter plastic reactor; the excess pressure of carbon monoxide (IV) was quickly created and sharply dropped in no longer than 90 seconds at a temperature of 25ºC and in no longer than 6 minutes at 6ºC. The obtained highly dispersed carbonate was studied microscopically, and a histogram of the particle size distribution was constructed. The optimum process time at room temperature is 60 seconds. The resulting product is characterized by a narrow particle size distribution with a maximum of about 2.5 µm. The particle size reduction occurs when either the reaction time or the temperature decreases. Aggregate stability of the suspension depends on the molar ratios of calcium hydroxide and carbon monoxide (IV). The activation energy of the reaction is 59 kJ / mol.

Controllable Synthesis of Calcium Carbonate with Different Geometry: Comprehensive Analysis of Particle Formation, Cellular Uptake, and Biocompatibility

Carefully designed micro- and nanocarriers can provide significant advantages over conventional macroscopic counterparts in drug delivery applications. For the successful delivery of bioactive comp...

Biomimetic Synthesis of Calcium Carbonate with the Assistance of Amino Acids

Two acidic amino acids (aspartic acid, glutamic acid) and four neutral amino acids (cysteine, serine, tyrosine, glycine) were used as inducers for calcium carbonate biomimetic synthesis. The results showed that aspartic acid introduced is more effective for the growth of aragonite, while glutamic acid used is more effective for the growth of vaterite. Compared to those acidic amino acids, neutral amino acids used lead to less aragonite or vaterite produced, and tyrosine and serine show stronger effects on the growth of aragonite and vaterite than cysteine and glycine. On the other hands, it was found that the increased concentration of amino acid shows positive effects on the growth of aragonite and vaterite. In addition, the enhanced concentration of calcium chloride results in the increased crystalline volume of calcite significantly, as well as the more orderly structure as shown in scanning electron microscopy investigation. Meanwhile, the high calcium chloride concentration indicates weak inhibitory effect on aragonite growth but no significant influence on the growth of vaterite.

Synergistic effects of the alternating application of low and high frequency ultrasound for particle synthesis in microreactors

Ultrasound (US) is a promising method to address clogging and mixing issues in microreactors (MR). So far, low frequency US (LFUS), pulsed LFUS and high frequency US (HFUS) have been used independently in MR for particle synthesis to achieve narrow particle size distributions (PSD). In this work, we critically assess the advantages and disadvantages of each US application method for the case study of calcium carbonate synthesis in an ultrasonic microreactor (USMR) setup operating at both LFUS (61.7 kHz, 8 W) and HFUS (1.24 MHz, 1.6 W). Furthermore, we have developed a novel approach to switch between LFUS and HFUS in an alternating manner, allowing us to quantify the synergistic effect of performing particle synthesis under two different US conditions. The reactor was fabricated by gluing a piezoelectric plate transducer to a silicon microfluidic chip. The results show that independently applying HFUS and LFUS produces a narrower PSD compared to silent conditions. However, at lower flow rates HFUS leads to agglomerate formation, while the reaction conversion is not enhanced due to weak mixing effects. LFUS on the other hand eliminates particle agglomerates and increases the conversion due to the strong cavitation effect. However, the required larger power input leads to a steep temperature rise in the reactor and the risk of reactor damage for long-term operation. While pulsed LFUS reduces the temperature rise, this application mode leads again to the formation of particle agglomerates, especially at low LFUS percentage. The proposed application mode of switching between LFUS and HFUS is proven to combine the advantages of both LFUS and HFUS, and results in particles with a unimodal narrow PSD (one order of magnitude reduction in the average size and span compared to silent conditions) and negligible rise of the reactor temperature.

Biomimetic mineralisation of calcium carbonate using xanthan gum as morphology control agent

Biomimetic synthesis of calcium carbonate (CaCO 3 ) with various sizes and morphologies using organic matrix has become an interesting hotspot. CaCO 3 was synthesised by the reaction of Na 2 CO 3 and CaCl 2 in the presence of xanthan gum (XG). The results showed that the fresh mineralised CaCO 3 /XG were microspheres with large surface area and porosity. The original CaCO 3 /XG microspheres transformed to brick-like CaCO 3 after ageing 7 days at 4°C. During the morphology transformation, CaCO 3 spheres rearranged by attaching to XG molecular, and transformed from a macroscopic view of CaCO 3 microspheres to a hexahedral structure related with the XG uncoiled single chains re-associating into loose several-fold helix. The study demonstrated that environmental effect coupled XG could be one feasible approach to regulate the structure of CaCO 3 .

Facile Synthesis of Uniform Calcite Microcubes and Their Enhanced Tribological Performance in Lithium-Based Commercial Grease

This study describes a facile synthesis of calcium carbonate (CaCO3) monodispersed fine particles from an abundant indigenous and economical source (quicklime) and its enhanced tribological performance as a green additive in commercial lithium grease (CLG). The effects of various experimental parameters on particle morphology were thoroughly examined, and the conditions were optimized. The synthesized uniform particles were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and thermogravimetric (TG) /differential thermal analysis (DTA), and their results confirmed the calcite structure of the synthesized particles. The friction and wear studies were carried out under the applied load of 0.863 N at an ambient temperature for 5 min. The tribological performance of various amounts (1–7%) of cubic-CaCO3 (CCC) particles in CLG showed that 5 wt. % of CCC was the optimum concentration as additive in the present case. For comparison purposes, a commercial CaCO3 powder was used and a decrease in the friction coefficient of CLG was observed to be 33.4% and 16.4% for 5 wt. % CCC and commercial CaCO3 additives, respectively. The significantly enhanced antiwear and antifriction performance of the optimum CCC-CLG in comparison with the blank and commercial CaCO3-additized CLG was quite encouraging, and extensive studies in a real machine-operating environment are in progress for evaluation of the CCC-CLG blend to be used as an economical, green, and high-performance lubricant in mechanical components.

Precipitation of Spherical Vaterite Particles via Carbonation Route in the Bubble Column and the Gas-Lift Reactor

Spherical vaterite particles were produced by carbonation of calcium chloride solution with addition of ammonia to facilitate CO2 absorption. Synthesis of calcium carbonate was carried out in a bubble column or gas-lift reactor. The course of the reaction was monitored by pH measurements. Precipitated solids were analyzed by Fourier-transformed infrared spectroscopy, x-ray powder diffraction and scanning electron microscopy, and the particle size distribution was determined by a laser diffraction method. Synthesized calcium carbonate products were mainly vaterite. The calcium chloride concentration and carbon dioxide volume fraction in a gas phase had the main impact on the size of the produced particles in both reactors. A slight decrease in the mean particle size was observed for the highest mixing intensity. Both tested reactors can be applied to produce vaterite particles, although formation of homogeneous non-agglomerated spherical particles in a gas-lift reactor required careful selection of the process parameters.

Effect of a lipopeptide biosurfactant on the precipitation of calcium carbonate.

Observing flora and fauna, it can be said that nature is a great architect. Nature can create amazing structures with unique properties that may find potential applications in industry. This phenomenon is why the biomimetic synthesis of calcium carbonate with various polymorphs, sizes and morphologies using natural biomolecules, such as proteins and polysaccharides, has become an interesting topic in recent years. This novel work uses natural surfactants produced by Bacillus species (surfactins) in the formation of calcium carbonate particles. Calcium carbonate was synthesized by the reaction of Na2CO3 and CaCl2. The effects of surfactin concentration and pH on calcium carbonate crystal growth were investigated. Precipitated calcium carbonate was characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The pore size and specific surface area were measured via the BET isotherm method. Surfactin molecules were observed to prevent the transformation of vaterite into calcite in the reaction system, especially at pH 8. Surfactin possesses two negatively charged groups (COO-), which have strong affinity towards metal ions at pH 8. When the surfactin concentration was 20 ppm, the surfaces of calcite crystals were punctuated by spherical and oval depressions. Surface roughness may substantially improve the properties of the obtained structures, for example, as inorganic templates for polymeric capsules.

Biomineralization of calcium carbonate controlled by biomolecules produced by Bacillus sp.

In this study, culture supernatant of Bacillus subtilis KP7 growing on liquid LB medium consisted of 2 % of molasses was used for calcium carbonate synthesis. Synthesis of the calcium carbonate structures was performed in a reactor by mixing CaCl2 and Na2CO3 solutions at 25°C. The calcium carbonate particles were characterized by optical microscopy, FTIR and XRD analysis. In addition, the size distribution and the value of zeta potential were determined. It was observed that properties of obtained calcium carbonate depend on the supernatant amount. The smallest crystals of pure calcite with disordered structure were obtained when the concentration of the cell-free supernatant was 5 % (v/v).

Synthesis of calcium carbonate in alkali solution based on graphene oxide and reduced graphene oxide

This paper reports a new approach of producing CaCO3 particles in alkali solution. CaCO3 particles with pure calcite structure were obtained from the reaction of water-dispersed graphene oxide (GO) or reduced graphene oxide (rGO) with either Ca(OH)2 or CaO. In Fourier Transform Infrared (FTIR) spectra, the pure calcite structure was demonstrated by fundamental bands at 1425 (ν3), 873 (ν2), and 712 cm−1 (ν4). The Raman spectra showed the characteristic peak of calcite structure at 1085 cm−1 (ν1). X-ray diffraction pattern (XRD) and X-ray photoelectron spectroscopy (XPS) analyses further confirmed that only the pure calcite phase of CaCO3 was formed in both synthesis approaches. Scanning electron microscopy (SEM), Energy dispersive X-ray analyzer (EDX), and High-resolution transmission electron microscopy (HRTEM) also confirmed that distorted cubic and rhombic calcite particles were obtained with GO, while the pine flower-like and flower-like particles were obtained with rGO, and the average crystallite sizes varied from 26 to 44 nm. The mechanism of the reaction was investigated and it was found that the decomposition of oxygen functional groups on the surface of GO or rGO in certain alkaline media to release CO, CO2, and water was a key process as the released CO2 further reacted with OH- and Ca2+ to form CaCO3. This demonstrated that both GO and rGO could be used as main reactants for the synthesis of calcite.

Stable Nano Calcite Synthesis

Synthesis of calcium carbonate (CaCO3) particles in the presence of a population of carbon dioxide (CO2) bubbles was investigated in the calcium hydroxide (Ca(OH)2) solution, which is a natural stabilizer for CaCO3. Possible chemical speciation reactions were presented for an inorganic synthesis of hollow nano-CaCO3 particles. In the progress of CaCO3 synthesis, some of the particles started to dissolve at their edges and turned into hollow nano-CaCO3 particles. Some of the pores closed at the end of crystallization as a result of dissolution-recrystallization mechanism. Hollow nano-CaCO3 particles with sizes of about 300 nm were synthesized with a narrow size distribution. It was concluded that the hollow nano-CaCO3 particles could be advantageous due to lower weights and higher surface areas.

Synthesis of Calcium Carbonate Micro Particles using Emulsion Membrane Process Applied for Drug Release Studies

The aim of this work is the synthesis of calcium carbonate (CaCO3) nano and microparticles and their application as biomaterials (vehicles) for the sustained release of doxycycline. CaCO3 micro particles were synthesized by water-in oil (W/O) emulsion method using emulsion liquid membranes with bis (2-ethylhexyl) phosphate (D2EHPA) as carrier, Span 80 as surfactant, and toluene and kerosene as organic solvents. The aqueous phases contained 1 M CaCl2, and 1 M Na2CO3, respectively. The Dynamic Light Scattering (DLS) data showed CaCO3 particles with sizes ranging from around 100 nm to 3500 nm. The CaCO3 particles with the average diameters around 600 nm attained an adsorbtion of doxycycline of maximum 97.9%, and a slow and steady release with a cumulative value of approximative 50% after ten days.

Synthesis of Calcium Carbonate and Calcium Sulfate by Bio-activated Method and Application in Stabilization of Sand Particles

Synthesis of Calcium Carbonate and Calcium Sulfate by Bio-activated Method and Application in Stabilization of Sand Particles

Synthesis and Characterization of β-Tricalcium Phosphate Derived From Haliotis sp. Shells.

To develop a methodology for the synthesis of β-tricalcium phosphate (β-TCP, Ca3(PO4)2) from the shell of Haliotis sp. (abalone shell) and to verify its characterization and biocompatibility. Calcium oxide (CaO) was synthesized from abalone shell by sintering and was suspended in distilled water to prepare calcium hydroxide (Ca(OH)2). For the synthesis of calcium carbonate (CaCO3), carbon dioxide was used to infuse Ca(OH)2 at pH 7.4. CaCO3 was reacted with phosphoric acid at pH 6.0 to obtain dicalcium phosphate (CaHPO4). Subsequently, β-TCP was synthesized by a chemical reaction between CaHPO4 and CaO at 950°C to 1100°C for 3 hours. Fourier transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) was performed to verify the physiochemical characteristics of the composite synthesized from abalone shell. FT-IR and XRD results showed that β-TCP was successfully synthesized from abalone shell. The synthesized β-TCP did not affect cell viability of either normal human oral keratinocytes or osteoblastic MG-63 cells. These data indicate that β-TCP synthesized from abalone shell is biologically safe. β-TCP (Ca3(PO4)2) synthesized from abalone shell can be used as a potential source of bone grafting material.

Biomimetic synthesis of calcium carbonate with different morphologies and polymorphs in the presence of bovine serum albumin and soluble starch

Calcium carbonate has been synthesized by the reaction of Na2CO3 and CaCl2 in the presence of bovine serum albumin (BSA) and soluble starch. Effects of various bovine serum albumin (BSA) and soluble starch on the polymorph and morphology of CaCO3 crystals were investigated. Crystallization of vaterite is favored in the presence of BSA and soluble starch, respectively, while calcite is favored in the presence of a mixture of BSA and soluble starch. The morphologies of CaCO3 particles in the presence of mixture of BSA and soluble starch are mainly rod-like, suggesting that the BSA, soluble and their assemblies play key roles in stabilizing and directing the CaCO3 crystal growth.

Biomimetic Regulation of Microbially Induced Calcium Carbonate Precipitation Involving Immobilization of Sporasarcina pasteurii by Sodium Alginate

Many researchers in the past decade have explored the controlled synthesis of calcium carbonate with specific size, morphology, and polymorphism. This study explored the biomimetic regulation of microbially induced calcium carbonate precipitation (MICP) via employing immobilization technology. Calcium alginate gel was used to immobilize Sporosarcina pasteurii, a urea-positive microorganism. CO32– was generated driven by ureolysis and reacted directly with Ca2+ that was cross-linked in sodium alginate to produce CaCO3 precipitation. Based on SEM, TEM, XRD, HRTEM, and SAED results, amorphous calcium carbonate, vaterite, and calcite appeared in order. This evolution of CaCO3 morphology and polymorphism apparently conforms to Ostwald’s rule. Various concentrations (1–3%) of sodium alginate caused different alginate molecules to form due to the collapse of calcium alginate gel carrying negative charges and exerting a significant influence on the morphology of CaCO3 from hexagonal vaterite to capsule-shaped vat...

Synthesis of calcium carbonate in trace water environments.

Calcium carbonate (CaCO3) was synthesized from diverse water-free alcohol solutions, resulting in the formation of vaterite and calcite precipitates, or stable particle suspensions, with the dimensions and morphologies depending upon the conditions used. The obtained results shed light on the importance of solvation during crystallization of CaCO3 and open a novel synthetic route for its precipitation in organic solvents.

Protein-Mediated Precipitation of Calcium Carbonate.

Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure’s growth in the investigated system. In this study, samples of CaCO3 particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to ‘stack-like’ structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO3 formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein.