Calcium Carbonate Solution Research Articles

Synthesis and Modification of Zeolite ZSM-5 Catalyst with Solutions of Calcium Carbonate (CaCO3) and Sodium Carbonate (Na2CO3) for Methanol to Gasoline Conversion

Abstract In this article, the ZSM-5 catalyst was used as the base catalyst and its structure was modified for conducting Methanol to Gasoline reactions. ZSM-5 catalyst reacts to the solutions with diverse concentrations of calcium carbonate (CaCO3) and sodium carbonate (Na2CO3), and consequently, some changes were applied to its internal structure. Thus, Methanol to Gasoline (MTG) process was carried out under pressure of 1 atm, the temperature of 400°C, and specific surface area of 300 m2g-1 on synthetic zeolite ZSM-5 catalyst by a fixed-bed reactor. Structure and morphology of the synthesized catalyst were investigated by XRD, FT-IR, SEM, XRF and BET analyses. The effect of CaCO3 and Na2CO3 solutions used for catalyst modification on the distribution of hydrocarbon products were studied and compared to ZSM-5 catalyst. The result of catalyst activity evaluation tests shows that the modified catalyst with a 0.1 molar solution of CaCO3 and Na2CO3 provides the highest selectivity and efficiency compared to the hydrocarbons in boiling point range of C6+ gasoline.

Behavioral Changes of Multipotent Mesenchymal Stromal Cells in Contact with Synthetic Calcium Phosphates in vitro

Migration, proliferation, and osteogenic differentiation of human adipose-derived (AD) multipotent mesenchymal stromal cells (MMSCs) during in vitro modeling of indirect contact with calcium phosphate (CP) or nanoparticles of synthetic hydroxyapatite (HA) have been studied. The results were registered with electrode (real-time cell analysis, RTCA) or visual (Cell-IQ) systems of long-term observation of cell cultures. Bulk specimens were use in a Cell-IQ® v2 MLF device as pure titanium substrates (10 × 10 × 1 mm3) covered by a CP relief (roughness index Ra = 2.4–4.4 μm) bilateral coating that was prepared by the micr-arc method from an aqueous solution of orthophosphoric acid (20 wt %), calcium carbonate (9 wt %), and synthetic HA (6 wt %). HA crystallites (1 mg/mL) were fabricated by mechanochemical synthesis and served as an irritant in RTCA investigation. The Cell-IQ system identified a 3.5- to 10-fold decrease in cell number at the interface with CP coatings with differing roughness during 14-day cell culturing. After 21 days, it was accompanied by a weak reduction of MMSC antigen expression (CD73, CD90, and CD105) as opposed to an increase in MMSC osteogenic differentiation and intercellular-matrix mineralization. In turn, HA nanodispersion reduced the speed of MMSC migration by 1.5 times (P < 0.001) during 25-h RTCA recording, which simulated cell invasion through the microporous membrane (8-μm diameter). Inhibition of migration and cell division with increased osteogenic differentiation of MMSCs has been suggested to be a possible effect of biodegradation products of synthetic CP materials.

Inhibition of calcium carbonate scaling by precipitation using secondary nucleation coupled to degassing with atmospheric air

Scaling by calcium carbonate precipitation is an important challenge during exploitation of geothermal water or geothermal district heating systems. Water decarbonation is a promising solution to mitigate calcium carbonate precipitation and reduce the scaling risks. In the current work, the decarbonation of geothermal water by coupling atmospheric air bubbling with seeding was investigated. For that, several operating conditions were studied and optimized such as air and water flows, hydrodynamics, residence time, and bubbling rate. Synthetic and real solutions were tested. To reveal the efficiency of the proposed process, the addition of chemicals was avoided. Results showed that, using continuously operating reactor and under optimized operating conditions, the decarbonation rate of a calcium carbonate solution tested (4 mmol/L of CaCO3, T = 50 °C) can exceed 30% without using chemicals. It was also shown that he residence time in the reactor is relatively short (2.5 min) and the protection of the walls from precipitate adherence was guaranteed.

Supersaturated calcium carbonate solutions are classical.

Mechanisms of CaCO3 nucleation from solutions that depend on multistage pathways and the existence of species far more complex than simple ions or ion pairs have recently been proposed. Herein, we provide a tightly coupled theoretical and experimental study on the pathways that precede the initial stages of CaCO3 nucleation. Starting from molecular simulations, we succeed in correctly predicting bulk thermodynamic quantities and experimental data, including equilibrium constants, titration curves, and detailed x-ray absorption spectra taken from the supersaturated CaCO3 solutions. The picture that emerges is in complete agreement with classical views of cluster populations in which ions and ion pairs dominate, with the concomitant free energy landscapes following classical nucleation theory.

Characteristics of calcium carbonate solution flowing in pipe

Issue of energy is important because energy is one of economic foundation to support a nation. Indonesia have abundant resources of renewable energy and it can be used as friendly energy source. Innovations continue to be developed to find the right method about good quality and cheap of energy sources that is widely available in nature. Calcium carbonate powder of shellfish are the one of the environmentally friendly materials that are available in nature. In this study, calcium carbonate are used in aqueous solution of water-ethylene glycol fluid with a ratio of 40:60. The purpose of this study is to determine characteristics and hydrodynamic behavior of non-Newtonian calcium carbonate solution that is flowed in a small pipe. Concentration of powder was from varied 100 ppm, 300 ppm and 500 ppm on the base fluid, respectively. The test was performed on a circular pipe with 4 mm of inner diameter, horizontally. Pressure drop was determined between two different points in which there were high pressure and low pressure taps by different data acquisition. Changes of friction factor value become a parameter of the indicator to drag reduction. The highest drag reduction in transition flow is about 26.3 % for the 300 ppm concentration with Reynolds number is around 3000.

Additives influence the phase behavior of calcium carbonate solution by a cooperative ion-association process.

Amorphous calcium carbonate (ACC) has been widely found in biomineralization, both as a transient precursor and a stable phase, but how organisms accurately control its formation and crystallization pathway remains unclear. Here, we aim to illuminate the role of biologically relevant additives on the phase behaviour of calcium carbonate solution by investigating their effects on the formation of ACC. Results show that divalent cations like magnesium (Mg2+) ions and negatively charged small organic molecules like aspartic acid (Asp) have little/no effect on ACC formation. However, the particle size of ACC is significantly reduced by poly(aspartic acid) (pAsp) with long chain-length, but no effect on the position of the phase boundary for ACC formation was observed. Phosphate (PO4 3-) ions are even more effective in reducing ACC particle size, and shift the phase boundary for ACC formation to lower concentrations. These phenomena can be explained by a cooperative ion-association process where the formation of ACC is only influenced by additives that are able to attract either Ca2+ ions or CO3 2- ions and, more importantly, introduce an additional long range interaction between the CaCO complexes and promote the phase separation process. The findings corroborate with our proposed model of ACC formation via spinodal decomposition and provide a more realistic representation of how biology can direct mineralization processes.

Influence of magnetic fields on calcium carbonate scaling in aqueous solutions at 150 °C and 1 bar

The experiments performed as a part of this study were conducted to evaluate the effect of magnetic field treatment upon the scale forming tendency of brine solution composed primarily of calcium bicarbonate ions. The reported results were generated using a Dynamic Scale Loop system with the brine solution exposed to a magnetic field generated by a 6480 Gauss magnet of grade N45SH in a diametrical orientation for 2.5s. Following magnetic exposure, the brine solution was exposed to an elevated temperature 150°C at 1bar to promote the formation of scale within a capillary tube. The extent of scaling was measured by recording the differential pressure across the tube as scaling proceeded.Three important conclusions regarding the effect of magnetic field treatment upon scale formation in calcium bicarbonate solutions were reached. Firstly, the ratio of calcium to bicarbonate plays a key role in determining how magnetic fields influence scale formation, whether promoting or inhibiting it. Solutions containing high concentrations of the bicarbonate, or equal concentrations of the bicarbonate and calcium species showed inhibited scale formation following magnetic exposure. Secondly, the electrical conductivity of the calcium carbonate solution was noticeably impacted by the exposure to the magnetic field through manipulation of the ionic hydration shell and may also provide a measure of the extent of scale formation. Finally, the application of magnetic field treatment for scale inhibition may provide an alternative eco-friendly scale inhibition strategy in place of traditional chemical scale inhibitors.

Effect of Calcium Carbonate on Compressive Strength and Physical Properties of Alkali-Activated Lightweight Concrete

This study presents the compressive strength and physical properties of alkali-activated lightweight concrete. Alkali-activated lightweight concrete was synthesized with fly ash, calcium carbonate and sodium hydroxide solution. Calcium carbonate was designed to replace part of fly ash at 5 and 10 wt.%. Sodium hydroxide solution at 5, 7.5 and 10 M was used as a liquid solution. Liquid to ash ratio (L/A ratio) at 0.45 was designed and aluminium powder was used as a foaming agent. The results showed that, the compressive strength of alkali-activated lightweight concrete made with fly ash was increased with NaOH concentration increased. The maximum compressive strength at 6.0 MPa was obtained from 10M NaOH mixture. For fly ash-calcium carbonate system, the compressive strength of lightweight concrete was improved when containing calcium carbonated, especially at 5 and 7.5 M NaOH mixtures. The maximum of compressive strength at 8.1 MPa and bulk density were obtained from the 5 wt.% calcium carbonated with 10M NaOH mixture. Water absorption and voids of all mixtures trend to decrease with increased NaOH concentration. XRD showed the sodium aluminum silicate hydrated as an alkali-activated product and composed of Si/Al atomic ratio at 2.1 and Na/Al atomic ratio at 1.4, respectively. Bulk density and compressive strength of alkali-activated lightweight concrete made with both fly ash and fly ash-calcium carbonated were acceptable in accordance with the specified criteria of TIS 2601. The well pore structure distribution of alkali-activated lightweight concrete was acceptable.

Carbonate Apatite Precipitation from Synthetic Municipal Wastewater

An important component of phosphorite (phosphate rock) is carbonate apatite, as it is required for phosphorous fertilizer production due to its increased phosphate solubility caused by carbonate substitution in the apatite mineral lattice. High phosphate concentrations in municipal wastewater treatment plants are commonly reduced by precipitating iron phosphate by addition of iron chloride. We investigated the possibility of precipitating carbonate apatite from a potential range of phosphate concentrations that could be available from municipal wastewater treatment plants with anaerobic digestion reactors (5 mM–30 mM). Synthetic phosphate solutions at neutral pH were mixed in batch experiments with a calcium carbonate solution produced by dissolving calcite in contact with carbon dioxide gas, with and without carbonate apatite seed. Batch experiments were used to identify the carbonate apatite supersaturation ranges for homogeneous and heterogeneous nucleation, and the precipitates analyzed with Raman spectroscopy, powder X-ray diffraction, inorganic carbon coulometry, and scanning electron microscopy. Some precipitates contained carbonate weight fractions within the range reported for geological phosphate rock (1.4–6.3 wt %). The precipitates were spherical, poorly crystalline carbonate apatite, suggesting an amorphous precursor transformed to a poorly crystalline carbonate apatite without changing morphology.

Qualitative discussion of prenucleation cluster role in crystallization of calcium carbonate under high concentration of magnesium based on experimental phenomena

Crystallization of calcium carbonate under high concentration of magnesium was studied. Interesting phenomena were observed. Approximately 80% of calcium ions stably existed in the solution up to 60min after amorphous calcium carbonate was separated by centrifugation, and induction time was significantly affected by concentration and feeding rate of sodium carbonate when other operating conditions remained unchanged. Experiments and computer simulation have proved that prenucleation cluster exists during crystallization of calcium carbonate in solutions. This paper tried to figure out specific crystallization process of calcium carbonate under high concentration of magnesium, and to interpret unforeseen phenomena combining with the idea of prenucleation cluster. With regarding prenucleation cluster which can incorporate magnesium into its structure as amorphous calcium carbonate, most of the phenomena including significant influence of local mixing could be better understood. Prenucleation cluster played an important role in crystallization of calcium carbonate, which was related to the induction time, morphology and final product, thus more fundamental studies of prenucleation cluster structure and magnesium role in it should be done.

Characterization and Kinetics of Calcium Sulfate Dihydrate Crystallization in the Presence of Trimesic Acid

AbstractIn this study, calcium sulfate dihydrate crystallization was studied within a mixed‐suspension, mixed‐product‐removal‐type crystallizer at 65 °C and 2.5 pH in pure media and in the presence of trimesic acid. The experiments were performed at different trimesic acid concentrations (250, 1000, and 2500 p.p.m.) through the reaction of calcium carbonate solution with sulfuric acid solution. The crystal size distributions (CSDs) and filtration rates of calcium sulfate dihydrate crystals were measured, and the crystals obtained were also analyzed by thermogravimetric analysis–coupled with Fourier transform infrared–mass spectrometry and scanning electron microscopy. It was determined that the length/width ratio of the crystals obtained in the trimesic acid additive media decreased compared with the crystals obtained in the pure media. Both the filtration rate and the average particle size decreased with an increase in trimesic acid concentration. The kinetics of crystal growth of calcium sulfate dihydrate has been analyzed on the basis of McCabe's ΔL law. It has been found that the growth rate of crystals depends on the particle size, which was specified using Abegg, Stevens, and Larson, Canning and Randolph, two‐parameter Mydlarz and Jones, and three‐parameter Mydlarz and Jones size‐dependent growth models. Results indicated that three‐parameter Mydlarz and Jones model ideally fitted for the characterization of the system because it has high relative coefficient and low square deviation. The presence of trimesic acid also led to a decrease in the growth rate of calcium sulfate dihydrate crystals. © 2017 Curtin University of Technology and John Wiley &amp; Sons, Ltd.

Calcite passivation by gypsum: the role of the cooperative effect

The overgrowth of gypsum (CaSO4·2H2O) on calcite (CaCO3), used as a substrate, has been obtained in order to verify the hypothesis of a crystallographic fit between the two phases. Lattice coincidences show that many orientations of gypsum with respect to calcite can occur. Experimentally, only two among these are fulfilled during the early stages of growth, the selection criterion reasonably being the adhesion energy. Moreover, it has been shown that the presence of calcium carbonate as a specific surface impurity in solution modifies the growth habit of gypsum acting on the growth rate and surface morphology of some gypsum forms. At high concentration, the calcium carbonate in solution promotes the twinning of gypsum according to the Montmartre law.

Retardation of heat exchanger surfaces mineral fouling by water-based diethylenetriamine pentaacetate-treated CNT nanofluids

Mineral scale deposition on heat exchanging surfaces increases the thermal resistance and reduces the operating service life. The effect is usually intensified at higher temperatures due to the inverse temperature solubility characteristics of some minerals in the cooling water. Scale formation build up when dissolved salt crystallize from solution onto the heated surface, forming an adherent deposit. It is very important for heat transfer applications to cope with the fouling problems in industry. In this present study, a set of fouling experiments was conducted to evaluate the mitigation of calcium carbonate scaling by applying DTPA-treated MWCNT-based water nanofluids on heat exchanger surfaces. Investigation of additive DTPA-treated MWCNT-based water nanofluids (benign to the environment) on fouling rate of deposition was performed. 300mgL−1 of artificially-hardened calcium carbonate solution was prepared as a fouling solution for deposit analysis. Assessment of the deposition of calcium carbonate on the heat exchanger surface with respect to the inhibition of crystal growth was conducted by Scanning Electron Microscope (SEM). The results showed that the formation of calcium carbonate crystals can be retarded significantly by adding MWCNT-DTPA additives as inhibition in the solution.

Studi Pengurangan Cemaran Gas Buang Sulfur Dioksida (So2) dari Emisi Cerobong Pabrik Nikel dengan Menggunakan Senyawa Kimia Penjerapamonium Hidroksida

Research on absorption of gaseous SO2 from factory emissions of nickel ore industry using solution of ammonium hydroxide has been done. Research conducted with variations including concentration, temperature, and time of contact. Variation of the concentration used were 1%, 2%, 3%, 4% and 5%; while variations of the temperature used were 20 o C, 25 o C, 30 o C, 35 o C, and 40oC; and the contact time were 10, 15, 20, 25 and 30 minutes. SO2 gas emissions sampling is done at a time when the factory operates at flow velocity and temperature conditions exhaust gas emissions. Results showed the greater concentration of the solution absorbing the greater the concentration of sulfur dioxide gas absorption, absorption temperature range between 30° C-40° C, and the longer the absorption of the greater number of SO2 absorption. A comparison of the percentage of the results of the average accumulation of absorption between absorbent solution (ammonium hydroxide) and slurry of calcium carbonate to reduce sulfur dioxide emissions to ambient air showed results still under the limestone slurry i.e. absorption capability comparison 95.00%: 62,91%. Difference in SO2 gas that is not absorbed out as emissions are still on top of the raw set quality standard (750 mg/m3). The gas is absorbed to form ammonium sulphate compounds that could be accommodated and packaged for commercialized as a by-product in the form of inorganic fertilizers valued economically. As such, ammonium hydroxide is used as an alternative to allow compound absorbent and produces no side residue so that the result is considered safe for the environment.

On the Phase Diagram of Calcium Carbonate Solutions

A liquid–liquid phase boundary is experimentally determined in calcium carbonate solutions obtained by rapid mixing. Nanoparticles of amorphous calcium carbonate form at concentration higher than this boundary and their size diverges close to the boundary, which is interpreted as a spinodal line. At lower concentrations, the solution is metastable against the nucleation of crystalline calcium carbonate phases. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Engineering a novel bilayer membrane for bone defects regeneration

We report the fabrication of a novel bilayer scaffold as a barrier membrane via modified-solvent casting and evaporation technique for the regeneration of bone defects. The blended solution of polycaprolactone (PCL) and calcium carbonate (CaCO3) was treated with hydrochloric acid (HCL), which resulted in the in situ formation of carbon dioxide (CO2) and water. This led to the phase separation between the PCL and calcium-based compounds and subsequently to the formation of a bilayer membrane. Surface morphology, surface wettability, and energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the formation of a bilayered construct with a PCL-rich thin layer on the upper surface and a calcium-rich porous layer on the lower surface. From the FE-SEM images, the PC30 membrane showed a smooth upper layer with pores less than 10µm diameter, whereas the lower layer contained many interconnected larger pores up to 1000µm diameter in addition to the visibly identified macrovoids. The cell adhesion assay showed that both surfaces of the membrane responded well to the cells. In addition, the upper surface prevented the down-growth of the fibroblasts. The initial results suggest a new strategy for the fabrication of the bilayer membrane for regenerative medicine.

Calcium incorporation in graphene oxide particles: A morphological, chemical, electrical, and thermal study

Surface chemical modification and functionalization are common strategies used to provide new properties or functionalities to a material or to enhance existing ones. In this work, graphene oxide prepared using Hummers' method has been chemically modified with calcium ions by immersion in a calcium carbonate solution. Transmission electron microscopy analyses showed that graphene oxide (GO) and calcium incorporated graphene oxide have a morphology similar to an ultra-thin membrane composed of overlapping sheets. X-ray diffraction and Fourier-infrared spectroscopy show that calcium carbonate residue was completely removed by hydrochloric acid washes. Energy dispersive X-ray spectroscopy mapping showed spatially homogeneous calcium in Ca-incorporated graphene oxide sample after HCl washing. This Ca is mainly ionic according to X-ray photoelectron spectroscopy, and its incorporation promoted a small reduction in the graphene oxide structure, corroborated also by four-point probe measurements. A thermal study shows a remarkable increase in the GO stability with the presence of Ca2+ ions.

How nature grows one tough biomineral

By weaving tiny bits of protein into the lattices of growing crystals, nature long ago figured out how to convert calcium carbonate, a brittle, fragile material, to the tough biomineralized form of calcite, the carbonate-based material from which seashells and some animal claws are made. Just recently, scientists figured out how nature does it. The new study shows that the mechanism controlling calcite crystallization is directed by surface chemistry, not simple physical processes, as had been commonly assumed. The findings could lead to new strategies for synthesizing tough composites and CO2 storage materials. Materials scientist James J. De Yoreo of Pacific Northwest National Laboratory described his team’s study at the American Chemical Society national meeting in San Diego last week. To probe the biomineralization process, De Yoreo and colleagues exposed a freshly cleaved calcite crystal to a concentrated water-based solution of calcium carbonate in an atomic force microscopy liquid sample

Fouling mitigation on heat exchanger surfaces by EDTA-treated MWCNT-based water nanofluids

Fouling can be defined as adherent deposits of unwanted compounds that are formed by the precipitation of soluble salts from water and crystal growth on the surfaces of processing equipment. The deposition layer becomes an insulating layer that deteriorates the heat transfer efficiency and shortens the service life. The development of functionalized nanomaterial leads to multi-functionality, such as the ability to adsorb scaling cations with high thermal conductivity, which is very important for heat transfer applications to manage the fouling problems. The purpose of this study was to evaluate the mitigation of calcium carbonate scaling by applying EDTA-treated MWCNT-based water nanofluids on heat exchanger surfaces. A set of fouling experiments was conducted by using additive EDTA-treated MWCNT-based water nanofluids (benign to the environment) to verify the additives’ retardation of the fouling rate of deposition. Fouling solution for deposit analysis was prepared by using 300 mg/L of artificially-hardened calcium carbonate solution. Also the assessment of the deposition of calcium carbonate on the heat exchanger surface with respect to the inhibition of crystal growth was conducted by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectrometry (EDS). The results showed that the formation of calcium carbonate crystals can be retarded significantly by adding MWCNT-EDTA additives to the solution.

Support vector machines for modelling phosphocalcic hydroxyapatite by precipitation from a calcium carbonate solution and phosphoric acid solution

The aim of this work was to develop an effective quantitative relationship model using support vector machines for the synthesis of phosphocalcic hydroxyapatite by precipitation from a calcium carbonate solution and a phosphoric acid solution. The model was created using a set of factors consisting of the pH of the reaction solution, the Ca/P molar ratio of the reagents, the reaction time and the initial concentration of calcium. Previous studies modelled these relationships using different classification techniques. In this paper, a novel approach based on support vector machines (SVMs) is introduced. This latter approach yields the best result compared to polynomial regression (PR), linear regression (LR) and artificial neural networks (ANN). In addition, the contribution of each descriptor is evaluated. Thus, the proposed method can be successfully used to predict the Ca/P analysis directly from the considered factors.