Synthesis Of CaCO3 Research Articles

Microbial induce carbonate precipitation derive bio-concrete formation: A sustainable solution for carbon sequestration and eco-friendly construction.

The microbial-induced calcium carbonate precipitation (MICP) technique has high potential in the development of bio-concrete, enhancing the strength, durability, and self-healing properties of construction materials. In this review work, we have explored the crucial role of microorganisms in carbon sequestration, microbial methods in CaCO3 synthesis, and the application of bio-concrete formation, based on the SCOPUS database from 2010 to 2024. The production of construction materials consumes a significant amount of energy, which can emit high amounts of carbon dioxide (CO2) into the atmosphere. As a sustainable solution, researchers are working to introduce novel construction biomaterials through MICP, which play a key role in CO2 sequestration to address this issue. Herein, microorganisms (bacteria) can utilize CO2 through multiple absorption processes, converting it into value-added compounds or inducing CaCO3 precipitation. For example, specific bacteria like Bacillus cereus, Bacillus sphaericus, Bacillus pasteurii, Bacillus subtilis, and Bacillus megatherium are known for their capability to thrive in alkaline conditions and play a key role in bio-concrete formation. Furthermore, it has been highlighted that the bio-concrete ability to sequester CO2 through the carbonation process, emphasizes the roles of urease activity and carbonic anhydrase (CA) in bio-concrete. Overall, this paper provides a complete synopsis of recent research on the formation of bio-concrete through MICP and the various elements influencing the technique, including cementation solution, temperature, injection, pH, and bacteria. This suggests that emerging trends in bio-concrete utilization could significantly reduce CO2 emissions while enhancing the strength of non-reinforced concrete.

Bioinspired transparent ultratough birefringent photonic films with engineerable interference colors derived from in-situ synthesis of CaCO3

Chameleons can rapidly modify their coloration by manipulating the arrangement of iridophores encompassing guanine crystals in their dermis, which enables incident light to undergo birefringence. Various biomaterials have been designed to mimic the arrangement of guanine crystals, yet instances of synthesizing bottom-up structures with anisotropy for optical functionality remain rare. In this study, we report a novel two-step gas diffusion method for in-situ synthesis of CaCO3 (Vaterite) within a hydrogel to fabricate a bio-photonic film displaying birefringence interference colors. This strategy enables the successful fabrication of an inorganic–organic photonic film with superior mechanical properties and flexibility, resulting in high transparency, superior toughness, and adjustable optical anisotropy. Through a combination of experiment and simulation results, we elucidated the critical role played by shape factor (distribution) and structural factor (particle size) in producing transmitted interference colors. Finally, the birefringent photonic films prepared using the dot-plate method can function as optical patterns accurately representing the “on”/“off” state within a binary system. This system offers high spatial resolution, excellent repeatability, and precise controllability of optical properties, making it applicable in fields such as information encryption and decrytion. Our study has successfully synthesized photonic material with anisotropic structure though in-situ method while elucidating the underlying mechanism governing their ability to generate transmission interference colors, thus opening up new avenues for transparent flexible polarized optics, imperceptible wearable devices, and advanced information encryption.

Synthesis of Calcium Carbonate from Orange Peel Waste Extract: A Mechanistic Investigation

The present work reports the mechanism and synthesis of calcium carbonate (CaCO3) formation from orange peel, which is one of the most common agriculture waste generated throughout the globe. The zest of oranges was co-distilled with distilled water to separate the essential oil content. Further, the residue was washed twice with distilled water to get the desired extract. For the green synthesis of CaCO3, a saturated solution of calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) was mixed thoroughly with orange peel extract in the 1:3 proportion. This solution was kept on magnetic stirrer while maintaining temperature at 85˚C, heated at 100˚C for 13 h which was further annealed at 300˚C, 500˚C and 700˚C. X-ray diffraction (XRD) shows the presence of calcite phase corresponding to CaCO3. Fourier transform infrared spectra (FTIR) exhibits the bands corresponding to Ca-O, C-O and vibrations of CO3-2 bonds whereas UV–Visible spectroscopy shows the optical behavior of CaCO3. The qualitative analysis of orange peel extract as well as the black-brown gel formed as a result of sol–gel synthesis method was examined using Gas Chromatography & Mass Spectrometry (GCMS). It revealed the presence of acidic groups (2,3-butanediol & 1,4-benzenediol) which led to the development of a mechanism, governing the formation of CaCO3.

THE EFFECT OF PRECURSOR CONCENTRATION, pH OF THE SOLUTION AND CARBONATION DURATION ON CACO3 PARTICLE SIZE VIA CARBONATION METHOD

Background. There are multiple techniques for generating CaCO3, one of which is the carbonation method. Currently, the particle size of CaCO3 is primarily determined by the combined influence of various variables. Objective. This study investigates the effect of precursor concentrations, pH of the solution, and carbonation duration on the size of CaCO3 particles Methods. The type of research in this study is experimental laboratory with a descriptive presentation of data. This study is divided into two stages: first, synthesis of CaCO3 with different concentration of precursors and carbonation duration. Second, it used different pH value of the solution and carbonation duration. The particle size of CaCO3 were characterized using the Particle Size Analyzer (PSA) (Horiba Scientific SZ-100 Nanopartica). Result. The result show the smallest CaCO3 at first stage, 548 nm, obtained at concentration of 0.75 M with carbonation duration of 30 minutes. The largest CaCO3-size, 6194 nm, is seen at a 0.5 M concentration with a carbonation duration of 10 minutes. The second stage show the smallest particle size, 1165 nm, obtained at a pH value of 8 with a carbonation duration of 60 minutes. Meanwhile, the largest size, 5621 nm, is obtaining at a pH value of 9 with a carbonation duration of 90 minutes Conclusion. The concentration of precursors and the duration of carbonation have no effect on the size of CaCO3 particles, however the pH value of the solution may affect the particle size of CaCO3. It is directly proportional to the pH value of the solution

A novel approach to assessing the antioxidant and anti-diabetic potential of synthesized calcium carbonate nanoparticles using various extracts of Ailanthus altissima.

Calcium carbonate nanoparticles (CaCO3) have been found to exhibit unique properties that show their potential to be used in various therapies. Green synthesis of CaCO3 has been progressively gaining ac-ceptance due to its cost-effectiveness and energy-efficient nature. In the current study, different extracts of Ailanthus altissima were used to synthesize the calcium carbonate nanoparticles the synthesis and characterization of CCNPs were confirmed by using Fourier Transform Infra-Red spectroscopy, UV-Vis spectroscopy, and Scanning Electron Microscopy (SEM). The antioxidant activities (hydrogen peroxide, phosphomolydbenum, and ferric reducing) of calcium carbonate nanoparticles were affirmed by a good range of percentages of inhibition against free radical scavenging. The antidebate assays of CCNPs were observed by in-vitro and in silico approaches in a range at various concentrations while maximum inhibition occurred. In conclusion, the current study depicted that conjugated CaCO3 with A. altissima has a good potential to cure oxidative stress and Type II diabetes and could be used in the future as biogenic nanomedicine for the treatment of other metabolic diseases.

Size Control of Biomimetic Curved-Edge Vaterite with Chiral Toroid Morphology via Sonochemical Synthesis.

The metastable vaterite polymorph of calcium carbonate (CaCO3) holds significant practical importance, particularly in regenerative medicine, drug delivery, and various personal care products. Controlling the size and morphology of vaterite particles is crucial for biomedical applications. This study explored the synergistic effect of ultrasonic (US) irradiation and acidic amino acids on CaCO3 synthesis, specifically the size, dispersity, and crystallographic phase of curved-edge vaterite with chiral toroids (chiral-curved vaterite). We employed 40 kHz US irradiation and introduced L- or D-aspartic acid as an additive for the formation of spheroidal chiral-curved vaterite in an aqueous solution of CaCl2 and Na2CO3 at 20 ± 1 °C. Chiral-curved vaterites precipitated through mechanical stirring (without US irradiation) exhibited a particle size of approximately 15 μm, whereas those formed under US irradiation were approximately 6 μm in size and retained their chiral topoid morphology. When a fluorescent dye was used for the analysis of loading efficiency, the size-reduced vaterites with chiral morphology, produced through US irradiation, exhibited a larger loading efficiency than the vaterites produced without US irradiation. These results hold significant value for the preparation of biomimetic chiral-curved CaCO3, specifically size-reduced vaterites, as versatile biomaterials for material filling, drug delivery, and bone regeneration.

Synthesis of CaCO3 supported nano zero-valent iron-nickel nanocomposite (nZVI-Ni@CaCO3) and its application for trichloroethylene removal in persulfate activated system

Nano zero-valent (nZVI) based composite have been widely utilized in environmental remediation. However, the rapid agglomeration and quick deactivation of nZVI limited its application on large scale. In this work, CaCO3 supported nZVI-Ni catalyst, namely nZVI-Ni@CaCO3 was prepared and used for the efficient removal of trichloroethylene (TCE) in PS oxidation process. The successful disbursement of nZVI-Ni on CaCO3 support material not only increased the surface area of nZVI-Ni@CaCO3 (69.45 m2/g) with respect to CaCO3 (5.92 m2/g) and bare nZVI (13.29 m2/g) but also improved the catalytic activity. XRD, XPS and FTIR analysis confirmed the successful formation of nZVI-Ni@CaCO3 nanoparticles. The nZVI-Ni@CaCO3 nanoparticles combined with PS had achieved complete removal of TCE (99.8%) with dosage of 36 mg/L and 1.34 mM respectively. These results showed that the use of CaCO3 as support material for nZVI-Ni could have significant influence on contaminant removal process. Scavenging and EPR tests validated the existence of SO4•–, OH• and O2•– radicals in PS/nZVI-Ni@CaCO3 system and highlighted the dominant role of SO4•– radicals in TCE removal process. HCO3ˉ ions and humic acid have shown adverse effect on TCE removal due to radical scavenging and buffering effect. Owing to improved catalytic activity and easy preparation, the nZVI-Ni@CaCO3 nanoparticles could be served as an alternative strategy for environmental remediation.

Bioinspired controllable CaCO3 synthesis from solid waste by an “all in one” amino acid-in strategy: Implication for CO2 mineralization

CO2 mineralization suffers from extensive consumption of acidic/alkaline reagents due to the limited kinetics, which necessitates the development of an atom/energy-efficient process. An “all in one” reagent amino acid-based Ca2+ leaching-CO2 mineralization process inspired by biomineralization was proposed. This study explored the interactions between amino acids and Ca leaching, CaCO3 pre-nucleation, nucleation, and growth by investigating the evolution of Ca concentration, solution turbidity and CaCO3 morphology in complex CFA. Promising Ca2+ leaching efficiencies were observed, being 51.1 %, 34.2 %, and 21.0 % for glycine (Gly), L-alanine (Ala), and L-arginine (Arg), respectively, negatively correlated with their pI but positively correlated with their bonding energy with Ca2+. These amino acids ultimately led to a CaCO3 production of Gly (114.8 g/kg) > Ala (78.2 g/kg) > Arg (54.5 g/kg) from CFA. Gly leachate remained transparent (1.23 NTU) in the first 3 min of CO2 bubbling even though the solution was supersaturated and then got turbid suddenly (6508.75 NTU in 10 min) as continued CO2 bubbling, indicating the inhibition of Gly on CaCO3 nucleation. Observations using Cryo-SEM confirm the presence of abundant CaCO3 nanoparticles in the early stages of mineralization, which later assemble into vaterite crystal particles with a sub-structure and coalesce into larger particles in Gly and Ala. Meanwhile, Arg inhibited calcite growth along the C-axis, leading to the formation of thin, blocky-like particles. Furthermore, 0.010 ∼ 0.027 mmol/g amino acids are occluded into the CaCO3, stabilizing the metastable vaterites and imparting thermal stability, which was believed to be associated with this multistep pathway involving a transient prenucleation cluster, nanoparticle precursor formation, and particle–particle coalescence.

Morphological control of CaCO3 superstructures in seawater: Insights into Ca-source anion influence and formation mechanism

This work provides crucial insights into the crystallization and morphogenesis of CaCO3 polymorphs in seawater at elevated temperatures. Using Ca source anions as a controlling factor, we modify the crystallization of CaCO3 and demonstrate that stable and intricate particle morphologies of CaCO3, such as hexagonal bipyramidal, disks, and twin structures, can be generated in seawater without surfactants. The synthesis of CaCO3 was accomplished through a direct hydrothermal method utilizing water-soluble Ca salts (calcium chloride, calcium nitrate, and calcium acetate) as Ca source and urea as a carbonate source. Depending on the specific source anions used, various morphological changes were observed. The CaCO3 prepared with the nitrate source yields vaterite as the major polymorph with hexagonal bipyramidal morphology. Pseudohexagonal prisms of aragonite were the primary product obtained with calcium acetate as the source. In contrast, chloride ions yielded vaterite and aragonite depending on the reaction temperature and time. The purity of CaCO3 prepared with seawater was > 94 % regardless of the Ca source. We observe that the phase formation follows the order of gypsum-vaterite-aragonite with an increase in hydrothermal reaction time. Further, we propose the formation mechanism of vaterite hexagonal bipyramidal and aragonite pseudohexagonal prism superstructures where directional aggregation of particles occurs in the presence of ammonium ions and seawater solvent. These findings, obtained through the exploration of seawater and different Ca sources, offer a comprehensive understanding of how source anions influence the selective formation of CaCO3 polymorph and its morphological tuning. This information can be applied to tailor the synthesis of CaCO3 for specific applications.

Carbon dioxide capture with aqueous calcium carbide residual solution for calcium carbonate synthesis and its use as an epoxy resin filler

Calcium carbide residue (CCR) is a waste obtained from the production of acetylene gas by the hydration reaction of calcium carbide. This residue is generated in large quantities annually and requires appropriate disposal. The main composition of the residue is calcium hydroxide (Ca(OH)2). Ca(OH)2 can react with CO2 gas and form CaCO3 particles. This process is well known but not very attractive since Ca(OH)2 is obtained from limestone using an energy-intensive thermal conversion process. This paper examined the synthesis of CaCO3 from CCR solutions by capturing CO2 with the aid of triethanolamine (TEA) solutions at doses of 0, 5, 10 and 20% w/w. The precipitated CaCO3 was characterized, and the application of CaCO3 as a filler in epoxy resin was tested. The results showed that the precipitated CaCO3 was mainly calcite, with a 76.6% yield. Cubic calcite was primarily obtained in TEA solutions, whereas small and agglomerated spherical vaterite and cubic calcite particles were formed in non-TEA solutions. The CaCO3-filled epoxy composites showed higher compressive strength than the neat resin. However, the transparency of specimen plates was reduced. These results can serve as guidelines for the application of CCR slurry filtrate obtained from the sedimentation ponds of acetylene plants and help to reduce the amount of wastewater that needs to be treated. CO2 gas from industrial flue gas combined with TEA solution could be applied to precipitate CaCO3 for carbon-neutral manufacturing.

Performance Enhancement of the Poplar Wood Composites Biomimetic Mineralized by CaCO3.

Inspired by the natural matrix-mediated biomineralization, wood composites were prepared by vacuum impregnation using the gel effect of sodium alginate (SA) on calcium ions, which improved the mechanical properties, flame retardant, and smoke suppression properties of the wood composites. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed that the SA inducer had promoted the orderly deposition and directional crystallization of calcium carbonate (CaCO3) inside the wood cell walls and intercellular spaces. The density and weight gain rate of the biomimetic mineralized wood showed that CaCO3 effectively adhered to the interior of wood with SA as an inducer. The compressive and flexural strengths were 15.65% and 37.66% higher than those of the control, respectively. Thermogravimetric analysis (TG) proved that SA alleviated the thermal decomposition and complete combustion of the mineralized wood and improved the thermal stability. Microcalorimetry (MCC) and cone calorimetry (CONE) analyses revealed that the maximum heat release rate (HRR), total heat release (THR), and the total smoke production (TSP) rate of the mineralized wood was reduced by 59.51%, 48.52%, and 51.67%, respectively, compared with those of the control. This research demonstrates the in situ synthesis of CaCO3 within the cellular microstructure of the poplar which is using it as a biotemplate. With the enhancement of the flame retardant property and others, the wood composite biomimetic mineralized materials modified by CaCO3 and SA could be utilized more widely in the construction industry or other fields.

Calcium carbonate: controlled synthesis, surface functionalization, and nanostructured materials.

Calcium carbonate (CaCO3) is an important inorganic mineral in biological and geological systems. Traditionally, it is widely used in plastics, papermaking, ink, building materials, textiles, cosmetics, and food. Over the last decade, there has been rapid development in the controlled synthesis and surface modification of CaCO3, the stabilization of amorphous CaCO3 (ACC), and CaCO3-based nanostructured materials. In this review, the controlled synthesis of CaCO3 is first examined, including Ca2+-CO32- systems, solid-liquid-gas carbonation, water-in-oil reverse emulsions, and biomineralization. Advancing insights into the nucleation and crystallization of CaCO3 have led to the development of efficient routes towards the controlled synthesis of CaCO3 with specific sizes, morphologies, and polymorphs. Recently-developed surface modification methods of CaCO3 include organic and inorganic modifications, as well as intensified surface reactions. The resultant CaCO3 can then be further engineered via template-induced biomineralization and layer-by-layer assembly into porous, hollow, or core-shell organic-inorganic nanocomposites. The introduction of CaCO3 into nanostructured materials has led to a significant improvement in the mechanical, optical, magnetic, and catalytic properties of such materials, with the resultant CaCO3-based nanostructured materials showing great potential for use in biomaterials and biomedicine, environmental remediation, and energy production and storage. The influences that the preparation conditions and additives have on ACC preparation and stabilization are also discussed. Studies indicate that ACC can be used to construct environmentally-friendly hybrid films, supramolecular hydrogels, and drug vehicles. Finally, the existing challenges and future directions of the controlled synthesis and functionalization of CaCO3 and its expanding applications are highlighted.

High selective synthesis of CaCO3 superstructures via ultra-homoporous interfacial crystallizer

Precise regulation of biomimetic mineralization for highly ordered superstructures is one of the perpetual concerns in biomaterial synthesis and crystal engineering. Herein, we propose a ultra-homoporous interfacial crystallizer (UHIC) as a novel interfacial microdevice, which has realized high selective synthesis of CaCO3 superstructures during Gas–Liquid reactive crystallization process. This UHIC with ultra-uniform mass transfer porous channel and interfacial superhydrophilicity render the droplet ultra-homo nucleation site and coordinatively regulate the interfacial nucleation energy. The highly precise microchannel in UHIC can control the CO2 gas flow rate and sufficient interfacial Gas–Liquid diffusion of the CaCO3 pre-nucleation cluster (PNC). By coordinating the PNC diffusion, self-organization and nucleus growth, the proportion of synthesized CaCO3 crystals with spherical and polyhedral structures both increased to higher than 96.77 %, and the crystal size distribution was very uniform (minimum C.V. =11.7%). Fundamental theory of CaCO3 synthesis with UHIC as a desire interfacial reactive were then outlined, which can shed light on the high-selective synthesis of the microscale biomaterials.

Sonochemical Synthesis of Vaterite-Type Calcium Carbonate Using Steamed Ammonia Liquid Waste without Additives.

Herein, metastable spheroidal vaterite calcium carbonate (CaCO3) was prepared using a simple ultrasound technique. The fabricated material comprises an irregular nanoparticle aggregate when steamed ammonia liquid waste, that is, (CaCl2) and (NH4)2CO3, is used as the raw material at atmospheric temperature, without any surfactants. The effects of ultrasound amplitude, probe immersion depth, and solution volume on particle properties were investigated. The obtained samples were identified and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and the Brunauer–Emmett–Teller technique. Our experiments show that the probe immersion depth and the reaction volume are the key parameters that impact the diameter size and size distribution of the fabricated spheroidal vaterite CaCO3 particles. The ultrasound amplitude considerably affected the particle size and the specific surface area. A possible formation mechanism for pure vaterite is proposed herein, which suggests that simple vaterite CaCO3 is formed owing to the special properties of steamed ammonia liquid waste and the synergistic effects of the ultrasonic system. This study may provide a new method for vaterite CaCO3 synthesis.

Maximizing the red emission of CaCO3:Eu3+ phosphors by using a Taguchi L9 orthogonal design

This work reports the structural, morphological and luminescent properties of CaCO3:Eu3+ phosphors synthesized by a precipitation method. Those phosphors were made under different conditions such as: mole ratio for Ca:CO3 (1:1, 1:2 and 1:3), pH (from 7 to 11), temperature (from 25 to 75 °C) and Eu3+ concentration (from 1 to 5 at.%). We used a Taguchis’ design (orthogonal L9 array) to find the optimum conditions that allow the synthesis of CaCO3:Eu3+ phosphors with the highest red emission intensity. After this, only 9 samples were synthesized. According to the X-ray diffraction patterns, all the samples presented a mixture of vaterite and calcite phases. Different morphologies were also observed by scanning electron microscopy such as porous microspheres, stacked pillars, microbelts or coalesced particles. We also measured the photoluminescence (PL) spectra for these 9 samples and calculated their integrated PL intensity. Those values were used as input in the ANOVA analysis, which was employed to find the critical parameters that affect the emission intensity of the samples. As a result, we found that the temperature and the mole ratio of Ca:CO3 are the most influential factors on the luminescent properties. We also employed the McCamy formula to calculate the correlated color temperature (CCT) and obtained values in the range of 1763–2797 K, which correspond to warm lighting sources. Moreover, the phosphor with the highest orange/red emission intensity presented a color purity of 96.66%, which is close to that used by the National Television Standard Committee (NTSC). Hence, the results presented here demonstrated that the CaCO3:Eu3+ phosphors could be used as a red-emitting component in White LEDs excited with UV chips.

Recycling CO2 from flue gas for CaCO3 nanoparticles production as cement filler: A Life Cycle Assessment

CaCO3 nanoparticles as filler have received considerable attention for the mechanical improvement that they provide to cements. However, their life-cycle impact on the environment remains almost unexplored, even if the cement industry is considered one of the largest CO2 emitters. In this perspective, this research work assessed a novel method for using CO2 from cement flue gases to produce nanoCaCO3 as cement filler within the cradle to cradle thinking. For this purpose, two routes of CO2 capture were assessed followed by the study of the synthesis of CaCO3 through a mineral carbonation. Three scenarios for the synthesis of CaCO3 nanoparticles were assessed targeting the use of waste or by-products as raw materials and recirculation of them to reduce any kind of emission. The three scenarios were evaluated by means of the Life Cycle Assessment methodology. Once the best considered route for nanoCaCO3 production was determined, this research work examined the environmental effect of including 2 wt% of CaCO3 nanoparticles into the cement. Closing the loop follows a circular economy approach since the CO2 is captured within the same cement factory. The results were compared with conventional Portland cement. Regarding nanoCaCO3 results, the scenario with simultaneous production of NH4Cl, and using as calcium source CaCl2 deriving from the soda ash Solvay process, proved to be the best option. Moreover, when cement was filled with 2 wt% of this nanoCaCO3, the benefit in terms of emission reductions in the Climate Change category was higher than 60 % compared to the conventional Portland cement.

Control of aragonite formation and its crystal shape in CaCl2-Na2CO3-H2O reaction system

Calcium carbonate (CaCO3) was synthesized in the CaCl2-Na2CO3-H2O reaction system at the reaction temperature of 40, 50, 60, and 70℃. The initial pH was changed to 2.4–11.0 at 50–70 ℃. The initial pH was adjusted by changing the pH of CaCl2 aqueous solution using HCl and NH3 aqueous solution. The CaCO3 precipitates obtained were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and specific surface area measurement. In the case of no adding the pH adjustment solution, the product was a mixture of calcite and vaterite at 40 ℃. The formation of aragonite was observed at ≥50 ℃, and single-phase aragonite was obtained at ≥60 ℃, according to XRD measurements. Thus, Aragonite could be synthesized by changing the reaction temperature. At 70 ℃, the synthesis of CaCO3 was performed by changing the initial pH of 2.4–11.0. The formation of single-phase aragonite was detected in the initial pH range of 2.4–10.4. However, a small amount of calcite was contained in aragonite at the initial pH ≥ 10.8. The crystal shape of obtained aragonite was needle-like, and its particle size became finer as the initial pH increased. At an initial pH 2.4, the length and width of the crystals were 2–7 μm and 0.5–1.0 μm, respectively. The finest particles were samples synthesized at the initial pH 11.0, its length and width were 1–2 μm and 0.1–0.2 μm, respectively. The specific surface area of the products was 4.12–14.88 m2 g−1 at the initial pH of 2.4–11.0. The particle size of aragonite could be controlled by changing the initial pH at 70 ℃.

Highly Stable and Fine-Textured Hybrid Microspheres for Entrapment of Cosmetic Active Ingredients.

This study details the preparation and application of supramolecular host–guest inclusion complexes entrapping biomineralized microspheres for long-term storage and their pH-responsive behavior. The microspheres were assembled using a CaCO3 synthesis process coupled with cyclodextrin–tetrahydrocurcumin (CD–THC) inclusion complexes, forming fine-textured and mechanically stable hybrid materials. The products were successfully characterized using field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and particle size analysis (PSA). Various parameters such as the Brunauer–Emmett–Teller (BET) surface area, single point total pore volume, and pore size via adsorption/desorption analysis were also determined. The obtained THC-entrapped hybrid microspheres contained as high as 20 wt % THC loading and were very stable, preserving 90% of the initial concentration over four weeks of storage at different temperatures, largely limiting THC leaching and indicating high stability in a physiological environment. In addition, the pH-responsive release of THC from the hybrid microspheres was observed, showing potential use for application to weakly acidic skin surfaces. To our knowledge, this is the first demonstration of antiaging cosmetic formulation technology using biomineralization based on the co-synthesis of CaCO3 and CD–THC complexes.

Synthesis of CaCO3 and trimethyl borate by reaction of ulexite and methanol in the presence of CO2

Abstract Developing CO2 capture and use of technologies to reduce anthropogenic emissions can be part of the solution against climate change. The purpose of this study is to develop a novel method to synthesize CaCO3 and trimethyl borate solution by utilizing and capturing carbon dioxide in a high pressure reactor. Dissolution of ulexite has been investigated to determine the effect of important working parameters by using Taguchi method. The parameters and their ranges were given as follows: reaction temperature, 80-120 °C; pressure, 10-30 bar; solid-to-liquid ratio, 5/100-20/100 g/mL; particle size, -106 + 75 μm-212 + 154 μm; stirring speed, 500-750 rpm; reaction time, 20-60 min. The findings of this research were given as follows: (1) the optimum operational conditions were found to be reaction temperature 120 °C, pressure 30 bar, solid to liquid ratio 0.05 g/ml, stirring speed 750 rpm, reaction time 60 min, particle size -154 + 106 μm, (2) 92.94 %of B2O3 was taken into solution under optimum condition (2) the sequestration capacity of CO2 was found to be 188 kg per ton ulexite (3) characterization of products by FTIR, SEM, XRD and ICP-OES confirmed that trimethyl borate and CaCO3 were synthesized. The utilization of CO2 in this process could sequester a considerably amount of CO2, therefore it can be contribute to decrease CO2 emission that causes greenhouse effect.

Optimization of CaCO3 synthesis through the carbonation route in a packed bed reactor

This article presents an investigation on the recovery of CO2 from the combustion gases of the cement industry through a carbonation route in order to obtain Calcium Carbonate Nanoparticles (CCnP), which could find application as either polymer or cement fillers. Two different experimental setups, a Continuously Stirred Bubbling Reactor (CSBR) and a Packed Bed Reactor (PBR), were studied in order to improve the final product and enhance the process yield. The influence of the experimental parameters on the particle size and morphology was tested for both reactors. The process was intensified by employing the PBR, where cubic calcite particles smaller than 300 nm were synthesized and higher CO2 conversions were obtained with respect to the CSBR performance.