Addition Of CaCO3 Research Articles

3D-imprinted superhydrophobic polyvinylidene fluoride membrane contactor incorporated with CaCO3 nanoparticles for carbon capture

Carbon capture using membrane gas absorption was limited by membrane wetting. In this work, superhydrophobic poly(vinylidene fluoride) (PVDF) membrane contactors were developed through 3D-imprinting and nanoparticle incorporation. Membranes were cast on woven support before phase inversion in a water bath to imprint the micro-roughness. The low-cost and biocompatible calcium carbonate (CaCO3) nanoparticles were blended into PVDF dope solution to build the hierarchical structure. The nanoparticles were premodified using stearic acid to reduce surface energy or removed using ethylenediaminetetraacetic acid for achieving nanotemplating. The presence of CaCO3 nanoparticles could be observed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The membrane hydrophobicity, pore size, and porosity were significantly improved due to the addition of CaCO3 and stearic acid-modified CaCO3 (SA-CaCO3). Removing CaCO3 nanoparticles enlarged the pore size greatly but affected the surface hydrophobicity slightly. The PVDF membrane incorporated with SA-CaCO3 achieved a CO2 permeation flux as high as 1.86 ± 0.05 × 10−2 mol m−2 s−1 and only showed slight changes in surface hydrophobicity after being immersed in amine solution for 50 h.

The physicochemical properties of Portland cement blended with calcium carbonate with different morphologies as a supplementary cementitious material

This study proposes the addition of calcium carbonate produced from flue-gas carbon dioxide to reduce carbon emissions of Portland cement manufacturing from 0.96 kgCO2/kg of Portland cement to 0.33 kgCO2/kg of Portland cement with comparable strengths. This study reviews the impact of calcite addition on properties of cement based on the literature. Experimental findings are presented on how the addition of different polymorphs of calcium carbonate influence physicochemical behaviour of Portland cement in terms of hydration chemistry, compressive and flexural strength and thermal analysis. Three polymorphs of calcium carbonate (amorphous, micro calcite and nano calcite) are studied. This is the first study to report the impact of three different calcium carbonate polymorphs especially that in the amorphous form. The addition of CaCO3 in Portland cement can increase the compressive strength by about 20% when compared to the benchmark. Examining the hydration shows the formation of scawtite and tilleyite with competing effect on the product strength during hydration. Formation of 8 mass% of combined scawtite–tilleyite phases at ambient conditions using CaCO3 is a new discovery; it results first in an increase in compressive strength and then, above 8 mass% it negatively impacts compressive strength. This study also provides avenues to use calcite as a sustainable supplementary cementitious material to reduce carbon emissions as well as improve early strengths. These characteristics are evidence that calcium carbonates provide a new regime of carbonate activity, modified hydration reactions, and can be used as a step towards the next generation of low-carbon Portland cements utilising mineral carbon capture technologies.

Torsion modulus with CaCO3 fillers in unsaturated polyester resin - mechanical spectroscopy

This work presents an alternative to studying and determining the torsion modulus, G, in composites. For this purpose, we use a measuring system with a rotation motion sensor coupled with a torsion pendulum that allows for determining the angular position as a function of the time. Then, through an equation derived from mechanical spectroscopy studies that permits the calculation of G’s value, the experiments focus on samples of different quantities of calcium carbonate (CaCO3) in unsaturated polyester resins. The results show that CaCO3 (33.33%W) fillers increase G’s value by 88% compared with unsaturated resin (100%W). Furthermore, there is a density increase of approximately 21% with the addition of CaCO3, considering the same two samples, which makes these composites the most massive. The relationship between G and composite density shows that it is possible to change the amount of CaCO3 to increase torsion resistance values in a controlled way.

Chloride impurity induced corrosion of nickel anode and its protection in molten Li2CO3-Na2CO3-K2CO3

It is well-known that Cl– can cause localized corrosion of metal in aqueous solutions, but its effect on material corrosion under anodic polarization in molten salts is less known. Herein, the effect of Cl– on the stability of nickel anode in molten Li2CO3-Na2CO3-K2CO3 was investigated. There existed a critical corrosion concentration of Cl– (0.2 mol% at 650 °C), above which serious corrosion of nickel anode took place. Cl– reduced the compactness and adherence of oxide scales. It was found that the addition of CaCO3 can effectively protect nickel anode from Cl– induced corrosion by increasing the electrolyte basicity.

3D-Printed Coaxial Hydrogel Patches with Mussel-Inspired Elements for Prolonged Release of Gemcitabine.

With the aim of fabricating drug-loaded implantable patches, a 3D printing technique was employed to produce novel coaxial hydrogel patches. The core-section of these patches contained a dopamine-modified methacrylated alginate hydrogel loaded with a chemotherapeutic drug (Gemcitabine), while their shell section was solely comprised of a methacrylated alginate hydrogel. Subsequently, these patches were further modified with CaCO3 cross linker and a polylactic acid (PLA) coating to facilitate prolonged release of the drug. Consequently, the results showed that addition of CaCO3 to the formula enhanced the mechanical properties of the patches and significantly reduced their swelling ratio as compared to that for patches without CaCO3. Furthermore, addition of PLA coating to CaCO3-containing patches has further reduced their swelling ratio, which then significantly slowed down the release of Gemcitabine, to a point where 4-layered patches could release the drug over a period of 7 days in vitro. Remarkably, it was shown that 3-layered and 4-layered Gemcitabine loaded patches were successful in inhibiting pancreatic cancer cell growth for a period of 14 days when tested in vitro. Lastly, in vivo experiments showed that gemcitabine-loaded 4-layered patches were capable of reducing the tumor growth rate and caused no severe toxicity when tested in mice. Altogether, 3D printed hydrogel patches might be used as biocompatible implants for local delivery of drugs to diseased site, to either shrink the tumor or to prevent the tumor recurrence after resection.

Evaluation, Effect of Whitening Agents on Physico-Chemical and Functional Properties of Sardine Surimi (Sardina pilchardus)

The effects of hydrogen peroxide (H2O2), sodium bicarbonate (NaHCO3) and calcium carbonate (CaCO3) treatments on the colour and textural properties of sardine surimi (Sardina pilchardus) were studied. Principal Component Analysis (PCA) was applied in order to investigate their effects and to determine the optimum whitening agents used. Addition of CaCO3 and H2O2 significantly improved whiteness of surimi in comparison to NaHCO3 treatments (p < 0.05). Some textural damage and a reduction in WHC values were observed for surimi treated withH2O2 and NaHCO3 (p < 0.05). PCA biplot showed that 1.5% CaCO3 tended to result in improved whiteness, WHC and textural properties since 1.5% CaCO3 sample sits closer to these functional properties vector lines than the other treatments. Whereas, 2.5% H2O2 had positively affected only the whiteness parameter. Results indicated that treating mince with the appropriate type and concentration of whitening agent can improve the functional properties of surimi, particularly from fish species with darker meat such as sardine.
 Aims: In order to improve whiteness and functional properties of sardine surimi (Sardina pilchardus), the effects of hydrogen peroxide (H2O2), sodium bicarbonate (NaHCO3) and calcium carbonate (CaCO3) treatments were studied. Principal Component Analysis (PCA) was applied in order to investigate their effects and to determine the optimum whitening agents used.
 Study Design: Experimental Research Design
 Place and Duration of Study: Research Unit “Biopreservation and Valorisation of Agro-Food Products” of the Higher Graduate School of Food Industry of Tunisia. The study was conducted in 3 months.
 Methodology: Sardine surimi samples were prepared with different treatments at different concentrations: calcium carbonate (CaCO3), hydrogen peroxide (H2O2) and sodium bicarbonate (NaHCO3). Proximate composition, total pigment, whiteness, water holding capacity and textural properties were investigated. Optimal levels of each whitening agent were determined using PCA.
 Results: Addition of CaCO3 and H2O2 significantly improved whiteness of surimi in comparison to NaHCO3 treatments (p < 0.05). Some textural damage and a reduction in WHC values were observed for surimi treated withH2O2 and NaHCO3 (p < 0.05). PCA biplot showed that 1.5% CaCO3 tended to result in improved whiteness, WHC and textural properties since 1.5% CaCO3 sample sits closer to these functional properties vector lines than the other treatments. Whereas, 2.5% H2O2 had positively affected only the whiteness parameter.
 Conclusion: Results indicated that treating mince with the appropriate type and concentration of whitening agent can improve the functional properties of surimi, particularly from fish species with darker meat such as sardine.

Stability, Microstructure, and Rheological Properties of CaCO3 S/O/W Calcium-Lipid Emulsions.

Calcium carbonate (CaCO3) is a commonly used fortified calcium, but poor suspension stability and easy precipitation seriously limited its food processing and products application. The formation of CaCO3 loaded microparticles based on the form of solid/oil/water (S/O/W) emulsion is a promising method to improve the dispersion stability of CaCO3 in liquid food. In this study, CaCO3, soybean oil, and sodium caseinate (NaCas) were used as the solid, oil, and W phase, respectively. The fabrication involved two steps: the S/O emulsion was prepared by adding CaCO3 into soybean oil by magnetic stirring and high-speed shearing, and then put the S/O crude emulsion into NaCas solution (W phase) to obtain S/O/W emulsion by high-speed blender. The particle size distribution, zeta potential, stability of the microsphere, infrared spectral analysis, and XRD of the S/O/W calcium-lipid microsphere were explored. The stability and rheological mechanism of S/O/W calcium-lipid emulsion were investigated by combining the microstructure, shear rheological, and microrheological properties. It was found that the emulsion particles have more uniform particle size distribution and no aggregation, and the stability of the emulsion was improved with increasing the content of NaCas. The mean square displacement (MSD) curve and solid-liquid equilibrium (SLB) value of S/O/W emulsion increased with the increase in NaCas concentration, and the viscosity behavior is dominant. The results of confocal laser microscopy (CLSM) and cryo-scanning electron microscopy (Cryo-SEM) showed that the three-dimensional network structure of S/O/W emulsions was more compact, and the embedding effect of calcium carbonate (CaCO3) was slightly improved with the increase in NaCas concentration. According to infrared spectrum and XDR analysis, the addition of CaCO3 into the emulsion system caused crystal structure distortion. This study provides a reference for solving the dispersibility of insoluble calcium salt in liquid food.

The Impact of Natural Calcium Carbonate and Ubiquinone on Bone Mineral Density in Rabbits

Objective: The aim of this study was to investigate the effect of ubiquinone and/or calcium carbonate (CaCO3) on bone mineral density in rabbits at healing site in mandibular bone postoperatively. Materials and Methods: Sixty healthy white male New Zealand rabbits almost the same age, weight and circumstance were used in this study. All animals were submitted to operation in the mandibular bone region. The groove of 2mm diameter and 6mm length was drilled by the heavy-duty dental engine. After operation rabbits were randomly divided into six groups (each group 10 rabbits) five rabbits for each period; control group (groove was not filled by anything) and treated groups which subdivided into five groups as follows: group I (groove was filled with Ubiquinone), group II (groove was filled with CaCO3), group III (groove was filled with CaCO3: Ubiquinone as a ratio (1:1)), group IV (groove was filled with CaCO3: Ubiquinone as a ratio (1:2)) and group V (groove was filled with CaCO3: Ubiquinone as a ratio (2:1)). Estimated BMD using Densitometry analysis was measured after 15 and 30 days respectively. Results: Statistical analysis showed significant differences between all groups (control and treated). The estimated BMD showed significant increase group I(101±1.05), group II(111±2.23), group III(125±3.54), group IV(126±5.13) and group V(133±6.29) comparing to control group (92±0.15) at follow-up times at 15 day. Also in the present study we found that significant decrease in BMD after 30 days of operation in group I(144±3.45), group II(153±6.24), group III(160±8.94), group IV(165±9.11) and group V(182±12.56) compare to control group(109±1.25) respectively. Adding the ubiquinone and/or CaCO3 showed a significant increase in BMD manifested by bone healing like space-filling and newly formed bone trabeculae and a high number of lacunas compared with the control group. Conclusion: This study concluded that the addition of ubiquinone and/or CaCO3 was successfully increasing in bone healing by increasing BMD compared with the control group. Keywords: Ubiquinone, CaCO3, Bone healing, BMD (Bone Mineral Density).

Development of self-cleaning bricks surfaces by CaCO3modified nano-TiO2 composite coatings

Recently, many studies have been carried out on self-cleaning characteristic because it is being regarded as one of the most interesting topics in biomimicry because of its potential applications in energy conversion, and biomedical and environmental protection. In this study, spin coating process has been introduced to coat bricks surfaces with TiO2 nanoparticles based polymer composite coatings modified using CaCO3 particles for self-cleaning and environmental purposes. The matrix solutions were prepared from Polystyrene. Particle size analyzing PSA and x-ray diffraction XRD were employed for characterization of the particles. The coatings were characterized by SEM and AFM techniques, and contact angle measurement CA. Results proved that CA increased with the increasing of PS ratio and additions of nano-TiO2 and CaCO3.The composite coatings have dense topography with roughness increased with increasing of the CaCO3 addition, and porous morphology characterized by clear distribution of the nano TiO2 particles and larger CaCO3 modification particles. Also, it could be concluded that the %20PS/%6TiO2/1gCaCO3 coatings, could give promised effect in modification of bricks surfaces from superhydrophilic substrates to Superhydrophobic with higher contact angle 167.3987°. This results will encourage the future research in surface engineering of bricks surfaces using CaCO3 particles for self-cleaning and environmental applications.

In Situ X-ray Diffraction at High Temperatures: Formation of Ca2SiO4 and Ternesite in Recycled Autoclaved Aerated Concrete

This study provides an insight into possible recycling processes for autoclaved aerated concrete (AAC) at low temperatures (<1000 °C). Belite binders were synthesized from wastes of AAC by the addition of CaCO3 and adaption of the molar CaO/SiO2 (C/S ratio) in the range of 2 to 2.5. An in situ XRD study performed during heating up to 1000 °C and subsequent quenching to room temperature evidenced the formation of ternesite besides C2S in sulfate-containing systems. Several factors influencing the reaction kinetics and the evolution of the phase composition were investigated thoroughly. Increased sulfate content and dwelling time during heating increase the ternesite content and promote the formation of highly crystalline α’H-C2S. The C/S-ratio of the starting materials has to be adjusted to the sulfate content in order to prevent the formation of ternesite at the expense of C2S. Ternesite remains stable during quenching to room temperature or even increases in amount, except in cases of very low cooling rates or high residual quartz contents (C/S-ratio ≤ 2). Temperature and range of α’H-C2S to β-C2S phase transition on quenching strongly depend on the cooling rate. The onset temperature for β-C2S formation varies between 540 °C (slow quench) and 450 °C (fast quench). Thermal expansion coefficients of ternesite are calculated showing similarity with C2S. The incorporation of CaSO4 modules in the structure switches the direction of maximum compression.

Impact of substrate supplemented with CaCO3 on mycelial growth, yield, morphological features and storability of fruiting bodies of black poplar mushroom Agrocybe cylindracea (DC.) Marie.

Black poplar mushroom, Agrocybe cylindracea deserves special attention, due to its medicinal properties. Water and alcohol extracts from fruiting bodies of the fungus have an anti-oxidant, anti-cancer, anti-fungal, cholesterol and triglycerides blood level lowering abilities. This mushroom is rich in proteins and vitamins, mineral elements and low in fat. The aim of the experiments was to determine effect of a substrate supplementation with CaCO3 on mycelial growth, yield, morphological features and storability of fruiting bodies of four strains of A. cylindracea (DC.) Marie. The amount of additive to sawdust substrate affects rate of mycelial growth and yield of investigated strains. A. cylindracea mycelial growth was not affected by addition of CaCO3 to substrate, however a significant effect of this additive was found on yield, which was the highest with CaCO3 addition in an amount of 8 g/100 g of substrate. Carpophores characterized with the largest caps diameter, and the largest individual mass obtained of substrate enriched with CaCO3 addition of 8 g/100 g of substrate. In addition, it was found that supplementation with CaCO3 affect storability of A. cylindracea. The lowest weight loss of fruiting bodies after 3 and 7 days of storage was found with addition of CaCO3 to substrate in an amount of 4 g/100 g of substrate.

Performance evaluation of basalt fiber-reinforced geopolymer composites with various contents of nano CaCO3

High carbon footprint of cement production is the major drawback of plain cement concrete resulting in environmental pollution. Geopolymer composites paste can be effectively used as an alternative to Portland cement in the construction industry for a sustainable environment. The demand for high-performance composites and sustainable construction is increasing day by day. Therefore, the present experimental program has endeavored to investigate the mechanical performance of basalt fiber-reinforced fly ash-based geopolymer pastes with various contents of nano CaCO3. The content of basalt fibers was fixed at 2% by weight for all specimens while the studied contents of nano CaCO3 were 0%, 1%, 2%, and 3%, respectively. The compressive strength, compressive stress-strain response, flexural strength, bending stress-strain response, elastic modulus, toughness modulus, toughness indices, fracture toughness, impact strength, hardness, and microstructural analysis of all four geopolymer composite pastes with varying contents of nano CaCO3 using scanning electron microscopy (SEM) were evaluated. The results revealed that the use of 3% nano CaCO3 in basalt fiber-reinforced geopolymer paste presented the highest values of compressive strength and hardness while the use of 2% nano CaCO3 showed the highest values of flexural strength, impact strength, and fracture toughness of composite paste. The SEM results indicated that the addition of nano CaCO3 improved the microstructure and provided a denser geopolymer paste by refining the interfacial zones and accelerating the geopolymerization reaction.

Investigation of properties change in the reacted molten salts after molten chlorides cyclic thermal treatment of toxic MSWI fly ash

To realize the thermal detoxification of municipal solid waste incineration (MSWI) fly ash in a relatively mild environment, molten salts thermal treatment technology was proposed in our previous research, which showed good effects. To investigate the properties of molten salts (NaCl-CaCl2) during cycling reusing, the change of the main components and the physical properties of the used molten salts were estimated. Results showed that the salts in fly ash would dissolve into molten salts. During this process, the concentration of K+, SO42- kept increasing while Cl- was decreased. The changing trend of Na+ and Ca2+ was dependent on the ratio of Ca/Na in raw fly ash. Ca(OH)2 in fly ash would react with CaCl2 to form CaClOH. Moreover, the introduction of the salt components on the thermal properties of molten salts were also studied. The melting point hardly changed by NaCl, CaSO4, and SiO2. Nevertheless, it was lowered to 431 °C with 15% CaCO3 addition, while increased to 523 °C with 20% KCl. Besides, there were no significant influences on the viscosity, stability, and thermal diffusivity of molten salts. KCl had the greatest influence on the specific heat capacity of molten salt, with an increase of about 20%.

An Investigation on the Flexural and Thermo-mechanical Properties of CaCO3/Epoxy Composites

Present work focused on the flexural and thermo-mechanical characteristics of epoxy based composites filled with 3 different calcium carbonate (CaCO3) concentrations: 1.5, 3 and 5 wt.%. Composite specimens were fabricated through conventional casting method and subjected to flexural test via 3 point bending fixture. Additionally, dynamic-mechanical analyzer (DMA) with single cantilever mode was used to reval the thermo-mechanical responses of samples. The findings showed that the filler concentration increase led to the increase of storage modulus (E') for all specimens while the glass transition temperature (Tg) slightly decreased for 1.5 wt. % CaCO3 filled epoxy composite. The 5 wt.% CaCO3 loaded composite showed maximum E' and Tg values with 10% and 1.5% improvement, respectively. Based on flexural test results it was surprisingly found that, 1.5% wt. CaCO3 addition attained the highest strength with almost 27% improvement among all samples. However, 5 wt.% CaCO3 introduced composites displayed the lowest mechanical performance due to the presence of agglomerates/tactoids, which was verified from SEM images as well.

Dehydrofluorination behavior of poly(vinylidene fluoride) during thermal treatment using calcium carbonate

Various fluorine compounds types, such as electrolytes and binders, are present in lithium-ion batteries (LIBs). The novel pyrometallurgical process is applicable for metal recovery from spent LIBs; however, it results in the emission of toxic fluorides such as hydrogen fluoride (HF). For the safe treatment of spent LIBs, we investigated HF emission behavior during thermal treatment of poly(vinylidene difluoride) (PVDF) as the binder model. To suppress the emission of HF, we also examined the effect of calcium carbonate (CaCO3) addition. It was found that HF emission was suppressed from 72% of total F for pure PVDF to 0.8% through CaCO3 addition. Fluorine was fixed as stable calcium fluoride.

Spent mushroom compost and calcium carbonate modification enhances phytoremediation potential of Macleaya cordata to lead-zinc mine tailings

Phytoremediation is an essential technique for mines' ecological restoration. Modifiers addition can alleviate the stress of heavy metals to plants and enhanced remediation efficiency. Herein, spent mushroom compost (SMC) and calcium carbonate (CaCO3) were added to lead-zinc mine tailings to reveal the mechanism of Macleaya cordata adaptive to heavy metals stress. Pot experiments were conducted in 100% tailing (T), 90% tailing + 5% SMC + 5% CaCO3 (T+), and 100% natural soil (NS). The results indicate that SMC and CaCO3 amendments could improve the structure and fertility of tailings, and promote the growth of M. cordata, increase the content of heavy metals accumulated in plants, enhance the synthesis of chlorophyll and increas the content of soluble protein in leaves; enhance the activities of antioxidase, that can protectcelluar components from oxidative damage. Moreover, most of Pb, Zn, and Cd existed in the cell wall and soluble components, adding SMC and CaCO3 could promote the conversion of Pb, Zn, and Cd to chemical forms with less toxicity and migratory capability. The results of transmission electron microscopy (TEM) and Fourier transform infrared spectrometer (FTIR) showed that SMC and CaCO3 could protect the structural integrity of cells and increase the contents of –OH, –COOH functional groups that can bind to heavy metals in cells. The addition of SMC and CaCO3 can alleviate the stress of heavy metals on M. cordata, enhancing its adaptability to heavy metals and phytoremediation capacity.

Effect of Ca2+ - Si4+ on Y3Al5O12:Ce ceramic phosphors for white laser-diodes lighting

Y2.985-xCe0.015CaxAl5-xSixO12 (YAG:1.5%Ce+xCS) ceramic phosphors (CPs) were synthesized by a vacuum sintering method. The addition of CaCO3 and SiO2 significantly reduces the sintering temperature of CPs. The effects of Ca2+ - Si4+ on luminescent properties and microstructures of YAG:Ce CPs are discussed. The Ca2+ - Si4+ cannot be completely dissolved in the YAG:Ce CPs when x reaches to 0.2. Combining the results of XRD, photoluminescence, and cathodoluminescence spectra proved the existence of the Ca2Al2SiO7. The performances of the titled CPs in high-power white laser diodes lighting are characterized.

Investigation and improvement of the desulfurization performance of molten carbonates under the influence of typical pyrolysis gases

Co-pyrolysis with oxygen-lean waste tires could improve the quality of pyrolytic oil from the bio-wastes while H2S/COS generated during co-pyrolysis process has a negative impact on the utilization of oil/syngas as well as the flue gas pollution control. Compared to traditional wet desulfurization process, high-temperature desulfurization via molten carbonates could reduce heat loss and favor the recycling of captured sulfur. Notably, small-molecule pyrolytic gases might change the species of sulfur-containing gases and promote the re-emission of absorbed sulfur from the molten salts. To fully understand the effects of pyrolysis gases (H2/CO/H2O/CO2) on molten salts desulfurization efficiency as well as mutual conversion mechanism of H2S and COS, equilibrium compositions calculations and adsorption experiments were carried out in the present study. The results showed that H2/CO had few effects on molten salts desulfurization performance and mutual conversion of H2S/COS. In contrast, CO2 and H2O had obvious adverse effects on desulfurization efficiency through the transferring of free S2− into emitted sulfur-containing gases. More specifically, only a small amount of CO2 reacted with S2− to produce COS while more S2− was converted to H2S and released from the reactor outlet when H2O was introduced. Fortunately, the impact of H2O or CO2 on molten salts desulfurization could be weakened with the addition of CaCO3 by transferring the molten free S2− into precipitated CaS. Besides, multi-stage desulfurization units connected in series and parallel were proposed and estimated, which was confirmed to show good performance to maintain the high desulfurization efficiency from the complicated pyrolytic gases.

Effects of added calcium-based additives on swine manure derived biochar characteristics and heavy metals immobilization

Although pyrolysis is a promising way for treating animal manure, the application is restricted with some limitations of biochar. To improve the quality of biochar derived from swine manure and enhance the immobilization of heavy metals (Cu and Zn) in it, swine manure was mixed with four types of Ca-based additives (CaO, CaCO3, Ca(OH)2, and Ca(H2PO4)2) prior to pyrolysis at 300–700 °C. The thermogravimetric characteristics of swine manure were obviously influenced The addition of CaO, CaCO3, and Ca(OH)2 during the whole decomposition process. Furthermore, with the addition of CaO and Ca(OH)2, the emission of CO2 and CO was substantially decreased at 200–500 °C, whereas the formation of CO, H2, CO2, and CH4 was drastically increased at 600–800 °C. The biochar produced with CaO addition had the highest pH, surface area and carbon content. Moreover, by addition of Ca-based additives, except for Ca(H2PO4)2, the transformation of labile Cu and Zn to the stable fraction was promoted, and the leachability and environmental risk of them were simultaneously reduced. In contrast, CaO and Ca(OH)2 were more favorable for the immobilization of Cu and Zn than CaCO3. Our study indicated that the catalytic pyrolysis using CaO was an effective and valuable method of animal manure treatment.

Segregation potency at [formula omitted] and [formula omitted] twin boundaries in Mg with Zn and Ca co-addition: A first-principles study

The co-segregation behaviors of Zn and Ca at {101¯2} and {101¯1} twin boundaries (TBs) were investigated by analyzing the segregation energy and strain field on atomic-scale structures through the first-principles method. We pinpointed the co-segregation patterns at TBs with larger Ca atoms and smaller Zn atoms occupying the extension and compression sites, respectively. The enhanced propensity for TB segregation was found in the studied Mg–Zn–Ca alloys with increasing Zn contents. Furthermore, strain field analysis was performed to demonstrate the role of elastic strain relief in promoting TB segregation. The results are conducive to selecting multiple elements that may tailor twin properties and inspiring for the development of new high-performance Mg alloys.