Synthesis Of Calcium Carbonate Research Articles

High local supersaturation formation for precipitated calcium carbonate synthesis by applying a rotating disk reactor

High local supersaturation formation for precipitated calcium carbonate synthesis by applying a rotating disk reactor

Facile surface-controlled synthesis of phytic acid-facilitated calcium carbonate composites for highly efficient ferric ion adsorption and recovery from rust

This work presents a simple synthesis of calcium carbonate (CaCO3)-based composites designed for the efficient adsorption of ferric ions (Fe3+) from solution, and specifically applied for Fe3+ recovery from rust. The strategy involves coordinating phytic acid (PA) with calcium ions (Ca2+) and coprecipitation with carbonate ions (CO32−) at room temperature to form phytate-CaCO3 (Ph-CC) composites. The obtained composites exhibited a robust mesoporous crystal structure with numerous phosphate groups of phytate functionalized on CaCO3 microparticles. The surface properties of the composites were optimized by adjusting the molar ratio (x) of PA:Ca2+ in synthesis. The Ph-CC0.10 composite (x = 0.10), with the highest specific surface area (99.56 m2/g), demonstrated exceptional Fe3+ adsorption (>99% efficiency in 80 min). The adsorption process followed the pseudo-second-order and Langmuir isotherm models, indicating monolayer coverage. Impressively, the maximum adsorption capacity reached 1385.85 mg/g, surpassing that of previously reported adsorbents. Thermodynamic studies confirmed a spontaneous and exothermic adsorption process. The superior Fe3+ adsorption of the composite was attributed to electrostatic and chelation interactions, with partial ion exchange. Furthermore, the Ph-CC0.10 composite effectively captured Fe3+ from rust dissolution in an acidic solution (pH 3) under sonication at 35 kHz for 60 min. These results highlight the potential use of the developed composites in mitigating environmental pollution and transforming waste materials into valuable sources. Therefore, Ph-CC composites are promising alternatives for wastewater treatment and metallurgical 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.

Recombinant Collagen-Templated Biomineralized Synthesis of Biocompatible pH-Responsive Porous Calcium Carbonate Nanospheres.

The synthesis of calcium carbonate with controlled morphology is crucial for its biomedical applications. In this study, we synthesized well-ordered porous calcium carbonate nanospheres using recombinant collagen as a biomineralization template. Porous collagen-calcium carbonate was created by incubating calcium chloride and sodium carbonate with collagen biotemplates at room temperature. Our results show that the recombinant collagen-calcium carbonate nanomaterials underwent a morphological transition from solid nanospheres to more porous nanospheres and a phase transformation from vaterite to a mixture of calcite and vaterite. This study highlights the crucial role of recombinant collagen in modulating the morphology and crystallinity of calcium carbonate nanoparticles. Importantly, the highly porous recombinant collagen-calcium carbonate hybrid nanospheres demonstrated superior loading efficacy for the model drug cefoperazone. Furthermore, the drug loading and releasing results suggest that hybrid nanospheres have the potential to be robust and biocompatible pH-responsive drug carriers. Our findings suggest that recombinant collagen's unique amino acid content and rodlike structure make it a superior template for biomineralized synthesis. This study provides a promising avenue for the production of novel organic-inorganic nanostructures, with potential applications in biomedical fields such as drug delivery.

Understanding Hierarchical Structure Construction Strategies and Biomimetic Design Principles: A Review

Organisms use gene and cell engineering to tailor the mineralization process and synthesize structure composites with special functions and favorable properties. This spurs scientists to design functional materials based on learning from nature. Herein, a systematic review of the biomimetic synthesis and hierarchical structure design of calcium carbonate–based minerals is presented. First, biomimetic synthesis strategies, including additive‐induced, template‐oriented, and gel‐mediated routes to direct the construction of the hierarchical structure, are reviewed. The molecular‐recognition technique and directional assembly pathway are then summarized to precisely describe the interactions between inorganic minerals and organic matter, and direct the mineral growth. Next, the underlying mineralization mechanisms governing the evolution of the complex morphology and structure are discussed. Nonclassical pathways that control mineral growth, including the theories of the amorphous phase, oriented attachment, mesocrystal formation, and liquid precursor, are concluded. Finally, herein, the applications of calcium carbonate–based minerals are discussed. Unique hierarchical structure endows minerals with special functions, including optical performance, biomedical applications, and environmental and ecological restoration. Overall, in this report, the biomimetic synthesis of calcium carbonate–based minerals is reviewed, covering the fundamental principles, construction of the hierarchical structure, underlying mechanisms of mineral growth, and functional designs.

Progress in the Preparation of Calcium Carbonate by Indirect Mineralization of Industrial By-Product Gypsum

To avoid the long-term pollution of land and water by industrial gypsum by-products, the exploitation of this resource has become a priority. The indirect synthesis of calcium carbonate from the industrial by-product gypsum has received substantial attention as a viable method for resource utilization. Currently, the primary problems in the indirect manufacture of calcium carbonate from the industrial by-product gypsum are additive recycling and process simplification. This paper describes the present state of development and compares various indirect mineralization systems. The factors affecting leaching and mineralization in the indirect mineralization of CO2 from by-product gypsum and the management of CaCO3 crystallinity are discussed, and the current additive regeneration cycle is summarized. The applications of other technologies in the indirect mineralization of by-product gypsum are also summarized, as are the obstacles, and required future work. This review provides guidelines for the laboratory indirect mineralization of by-product gypsum as well as practical applications.

Mechanisms of carbonate precipitation induced by two model bacteria

The investigation of microbially induced calcium carbonate precipitation is essential to understanding CO2 fixation, marine carbonate rock formation, and biogeochemical cycling of life-essential elements. In this study, two model bacteria Bacillus subtilis (possess the cell wall of G+ bacteria) and Escherichia coli (possess the cell wall of G− bacteria) were used as representatives to induce carbonate mineralization. The mineralization ability of the two bacteria and carbonate precipitation mechanisms were studied with the biochemical analysis of bacterial fermentation products, mineral characterization, and biomimetic mineralization experiments. The results showed that both bacteria induced biomineral formation by using the cell wall as a template, but B. subtilis was more capable of inducing mineralization than E. coli. Particularly, the percentage of Ca2+ removal from the culture medium by the former reached 36% in 7 days, which induced the formation of vaterite and calcite, while that of Ca2+ removal by the latter reached 28%, and the resulting carbonate was amorphous calcium carbonate. Biomimetic mineralization experiments showed that protein molecules were the key factors inducing the formation of biological vaterite, while polysaccharides tended to bind small vaterite particles to form large organo-mineral aggregates. By comparing the results of inducing calcium carbonate under the same culture conditions, the two types of bacteria with completely different cell wall structures had significant differences in the ability to induce calcium carbonate synthesis, among which that was stronger by Bacillus subtilis (G+) than by Escherichia coli (G−). It was found that factors such as bacterial cell wall structure, extracellular secretions including carbonic anhydrase, pH value, etc. all affect the microbial-induced carbonate precipitation to varying degrees, providing new insights into the theory of bacterial-induced carbonate mineralization.

Investigation of Thermophysical and Rheological Properties of Scallop Shell Powder/SAE 5w-30 Nanolubricant

Nanolubricant is a type of nano fluid that contains base-fluid lubricant (water or oil) and nanoparticles. This study aims to analyze the thermophysical and rheological properties of lubricants with the addition of nanoparticles. The nanoparticles used are Calcium Carbonate (CaCO3) made from scallop shell waste. The base lubricant is SAE 5W-30 synthetic oil which has quite good performance. Synthesis of Calcium Carbonate (CaCO3) into SAE 5W-30 lubricant uses a two-step method. Variations in the addition of volume fraction of Calcium Carbonate (CaCO3) of 0.05%, 0.10%, 0.15%. Furthermore, the nanolubricant was tested for its thermophysical properties which included thermal conductivity, specific heat, density, viscosity, and sedimentation. After that, the rheology of the nanolubricant can be known from the viscosity data by calculating the shear rate and shear stress.

Self-Healing Concrete: Concepts, Energy Saving and Sustainability

The production of cement accounts for 5 to 7% of carbon dioxide emissions in the world, and its broad-scale use contributes to climate imbalance. As a solution, biotechnology enables the cultivation of bacteria and fungi for the synthesis of calcium carbonate as one of the main constituents of cement. Through biomineralization, which is the initial driving force for the synthesis of compounds compatible with concrete, and crystallization, these compounds can be delivered to cracks in concrete. Microencapsulation is a method that serves as a clock to determine when crystallization is needed, which is assisted by control factors such as pH and aeration. The present review addresses possibilities of working with bioconcrete, describing the composition of Portland cement, analysis methods, deterioration, as well as environmental and energetic benefits of using such an alternative material. A discussion on carbon credits is also offered. The contents of this paper could strengthen the prospects for the use of self-healing concrete as a way to meet the high demand for concrete, contributing to the building of a sustainable society.

A Primary Study on Mechanical Properties of Heat-Treated Wood via in-situ Synthesis of Calcium Carbonate

This study aims to improve the value of fast-growing wood and extend the heat-treated wood utilization using inorganic calcium carbonate (CaCO3) crystals via an in-situ synthesis method. CaCl2 and Na2CO3 solutions with a concentration ratio of 1:1 were successively introduced into the thermally modified poplar wood obtained by steam heat treatment (HT) at 200°C for 1.5 and 3 h, resulting in the in-situ synthesis of CaCO3 crystals inside the heat-treated wood. The filling effect was best at the concentration of 1.2 mol/L. CaCO3 was uniformly distributed in the cell cavities of the heat-treated wood, and some of the crystals were embedded in the fissures of the wood cell walls. The morphology of CaCO3 crystals was mainly spherical and rhombic polyhedral. Three main types of CaCO3 crystals were calcite, vaterite, and aragonite. The HT of poplar wood at 200°C resulted in degrading the chemical components of the wood cell wall. This degradation led to reduced wood mechanical properties, including the surface hardness (HD), modulus of rupture (MOR), and modulus of elasticity (MOE). After CaCO3 was in-situ synthesized in the heat-treated wood, the HD increased by 18.36% and 16.35%, and MOR increased by 14.64% and 8.89%, respectively. Because of the CaCO3 synthesization, the char residue of the 200°C heat-treated wood samples increased by 9.31% and the maximum weight loss rate decreased by 19.80%, indicating that the filling with CaCO3 cannot only improve the mechanical properties of the heat-treated wood but also effectively enhance its thermal stability.

Utilization of green mussel shell waste for calcium carbonate synthesis through the carbonation method with temperature variation

In this study, PCC (precipitate calcium carbonate) was synthesized from green mussel shell waste via calcination and subsequent carbonation methods. Organic substances were removed from green mussel shell powder using a 5-hour calcination at 900 °C. Furthermore, the carbonation method was used in the Ca (NO3)2 solution at constant stirring speed with pH control by NH4OH, followed by the injection of carbon dioxide at 50, 70, and 90 °C temperature variations to precipitate calcium as CaCO3 (PCC). According to Rietveld’s quantitative XRD analysis, PCC products at 50 °C, 70 °C, and 90 °C exhibited primarily calcite and aragonite phases, with a significant needle-like morphology of aragonite growth during synthesis. Aragonite growth appears to have increased with increasing temperature. The results show that a simple, low-cost approach to green recycling works.

Probabilistic nucleation governs time, amount, and location of mineral precipitation and geometry evolution in the porous medium

One important unresolved question in reactive transport is how pore-scale processes can be upscaled and how predictions can be made on the mutual effect of chemical processes and fluid flow in the porous medium. It is paramount to predict the location of mineral precipitation besides their amount for understanding the fate of transport properties. However, current models and simulation approaches fail to predict precisely where crystals will nucleate and grow in the spatiotemporal domain. We present a new mathematical model for probabilistic mineral nucleation and precipitation. A Lattice Boltzmann implementation of the two-dimensional mineral surface was developed to evaluate geometry evolution when probabilistic nucleation criterion is incorporated. To provide high-resolution surface information on mineral precipitation, growth, and distribution, we conducted a total of 27 calcium carbonate synthesis experiments in the laboratory. The results indicate that nucleation events as precursors determine the location and timing of crystal precipitation. It is shown that reaction rate has primary control over covering the substrate with nuclei and, subsequently, solid-phase accumulation. The work provides insight into the spatiotemporal evolution of porous media by suggesting probabilistic and deterministic domains for studying reactive transport processes. We indicate in which length- and time-scales it is essential to incorporate probabilistic nucleation for valid predictions.

Controlling Calcium Carbonate Particle Morphology, Size, and Molecular Order Using Silicate

Calcium carbonate (CaCO3) is one of the most abundant substances on earth and has a large array of industrial applications. Considerable research has been conducted in an effort to synthesize calcium carbonate microparticles with controllable and specific morphologies and sizes. CaCO3 produced by a precipitation reaction of calcium nitrate and sodium carbonate solution was found to have high polymorphism and batch to batch variability. In this study, we investigated the polymorphism of the precipitated material and analyzed the chemical composition, particle morphology, and crystalline state revealing that the presence of silicon atoms in the precipitant is a key factor effecting particle shape and crystal state. An elemental analysis of single particles within a polymorphic sample, using energy-dispersive X-ray spectroscopy (EDS) conjugated microscopy, showed that only spherical particles, but not irregular shaped one, contained traces of silicon atoms. In agreement, silicon-containing additives lead to homogenous, amorphous nanosphere particles, verified by X-ray powder diffraction (XRD). Our findings provide important insights into the mechanism of calcium carbonate synthesis, as well as introducing a method to control the precipitants at the micro-scale for many diverse applications.

In Situ TEM Imaging of Solution-Phase Chemical Reactions Using 2D-Heterostructure Mixing Cells.

Liquid-phase transmission electron microscopy is used to study a wide range of chemical processes, where its unique combination of spatial and temporal resolution provides countless insights into nanoscale reaction dynamics. However, achieving sub-nanometer resolution has proved difficult due to limitations in the current liquid cell designs. Here, a novel experimental platform for in situ mixing using a specially developed 2D heterostructure-based liquid cell is presented. The technique facilitates in situ atomic resolution imaging and elemental analysis, with mixing achieved within the immediate viewing area via controllable nanofracture of an atomically thin separation membrane. This novel technique is used to investigate the time evolution of calcium carbonate synthesis, from the earliest stages of nanodroplet precursors to crystalline calcite in a single experiment. The observations provide the first direct visual confirmation of the recently developed liquid-liquid phase separation theory, while the technological advancements open an avenue for many other studies of early stage solution-phase reactions of great interest for both the exploration of fundamental science and developing applications.

The Properties of White Mineral Trioxide Aggregate (WMTA) Made of Rice Husk Ash Silica and Limestone Calcium Carbonate and the Effect of Silica Particles Addition

White Mineral Trioxide Aggregate (WMTA) using a combination of precursors consisting entirely of SiO2, CaCO3, Al2O3, and Bi2O3 which are widely used as cement for tooth restoration has been prepared. SiO2 was extracted from rice husk ash containing about 85-95% of silica found in rice husk ash from complete combustion. On the other hand, rice husks, in general, are still regarded as agricultural waste resulting from the rice milling process. In the rice milling process, around 20-30% of rice is obtained, and around 14-20% of ash is produced from burning rice husks. CaCO3 can be synthesized from limestone and it contains about 95% calcium carbonate. In this research, the researcher made WMTA from rice husk silica and CaCO3 from limestone. This research was carried out in several stages of silica extraction from rice husk ash using the high-purity sol-gel method, then the synthesis of calcium carbonate with the carbonation method obtained precipitated calcium carbonate (PCC). Preparation of WMTA by reacting silica sonicated + PCC + Al2O3 accompanied by stirring and heating 85 °C for 24 hours for homogenization, gelation, and maturation processes will be obtained by MTA’s gel. The MTA gel dried and calcined 1000 °C for 3 hours to obtain a white powder, the final product was added Bi2O3 of 18% produced high-quality WMTA. The results of making WMTA and modification silica of rice husk ash and PCC from limestone were characterized using XRD, FTIR showed characters that had similarities with WMTA ProRoot and had better diameter tensile strength test capabilities.

Generality of liquid precursor phases in gas diffusion-based calcium carbonate synthesis

We confirm the presence of liquid calcium carbonate precursor species in absence of additives in gas diffusion systems.

Calcium carbonate synthesis from waste concrete for carbon dioxide capture: From laboratory to pilot scale

This research article explains the synthesis and scale-up of calcium carbonate (CaCO3) from waste concrete as calcium-rich material by an inorganic carbonation process. The operating parameters include S/L ratio, HCl concentration, contact time, and extraction pH were investigated. The calcium hydroxide (Ca(OH)2) was synthesized by reaction between calcium chloride (CaCl2) and sodium hydroxide (NaOH), which induced the spontaneous reaction of CaCO3 without additional energy consumption. The productivity of CaCO3 was 1 kg/d in the laboratory scale experiment, and the CaCO3 productivity was scale-up to 20 kg/d through pilot scale process by same way as the laboratory scale. The approximately 4800 g of CaCO3 was produced and 2112 g of CO2 was captured per each cycle operation. Consequently, considered power consumption, the estimated amount of reduced CO2 was 465 g of CO2 in the pilot-scale reactor per cycle and produced CaCO3 with a purity of 99.0 %.

Optimization of Milling Procedures for Synthesizing Nano-CaCO3 from Achatina fulica Shell through Mechanochemical Techniques

The possibility of obtaining calcium carbonate nanoparticles from Achatina fulica shell through mechanochemical synthesis to be used as a modifying filler for polymer materials has been studied. The process of obtaining calcium carbonate nanopowders includes two stages: dry and wet milling processes. At the first stage, the collected shell was dry milled and undergone mechanical sieving to ≤50 μm. The shell particles were wet milled afterward with four different solvents (water, methanol, ethylene glycol, and ethanol) and washed using the decantation method. The particle size and shape were investigated on transmission electron microscopy, and twenty-three particle counts were examined using an iTEM image analyzer. Significantly, nanoparticle sizes ranging from 11.56 to 180.06 nm of calcium carbonate was achieved after the dry and wet milling processes. The size particles collected vary with the different solvents used, and calcium carbonate synthesis with ethanol offered the smallest organic particle size with the average size ranging within 13.48-42.90 nm. The effect of the solvent on the chemical characteristics such as the functional group, elemental composition, and carbonate ion of calcium carbonate nanopowders obtained from Achatina fulica shell was investigated. The chemical characterization was analyzed using Fourier transform infrared (FTIR) and a scanning electron microscope (SEM) equipped with an energy-dispersive spectroscope (EDX). The effect of milling procedures on the mechanical properties such as tensile strength, stiffness, and hardness of prepared nanocomposites was also determined. This technique has shown that calcium carbonate nanoparticles can be produced at low cost, with low agglomeration, uniformity of crystal morphology, and structure from Achatina fulica shell. It also proved that the solvents used for milling have no adverse effect on the chemical properties of the nano-CaCO3 produced. The loading of calcium carbonate nanoparticles, wet milled with different solvents, exhibited different mechanical properties, and nanocomposites filled with methanol-milled nano-CaCO3 offered superior mechanical properties.

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.