Addition Of Calcium Carbonate Research Articles

Alpine Pioneer Plants in Soil Bioengineering for Slope Stabilization and Restoration: Results of a Preliminary Analysis of Seed Germination and Future Perspectives

Stabilization of slopes subject to landslide by measures with low impact, such as those of bioengineering, is a topic of interest. The use of scarcely studied alpine pioneer plants could contribute to innovation in soil bioengineering and restoration ecology but to use them, knowledge of the ex situ germinability of their seeds is fundamental. This research analysed the germinability of seeds of nine alpine pioneer species (Papaver aurantiacum, Rumex scutatus, Tofieldia calyculata, Pulsatilla alpina, Silene glareosa, Adenostyles alpina, Dryas octopetala, Laserpitium peucedanoides and Laserpitium krapfii) treated with water, gibberellic acid (GA3) and/or calcium carbonate at room temperature. The seeds had different responses to the treatments: Laserpitium peucedanoides, L. krapfii and Silene glareosa showed difficulty in germinating (germination < 2.5%), while Dryas octopetala had good germination (39–61%) regardless of treatment. GA3 significantly increased the seed germination rate of Papaver aurantiacum, Pulsatilla alpina, Rumex scutatus and Tofieldia calyculata, while the addition of calcium carbonate made the seeds of Rumex scutatus and Tofieldia calyculata germinate more quickly. Results are discussed focusing on the perspectives of using alpine pioneer species in future soil bioengineering work for slopes stabilization and restoration, and on the actions that stakeholders should take to make this happen.

Calcium carbonate and ammonium polyphosphate flame retardant additives formulated to protect ethylene vinyl acetate copolymer against fire: Hydrated or carbonated calcium?

AbstractIn this study, the effect of the chemical nature of different calcium (Ca)‐based minerals as flame retardant additives in combination with ammonium polyphosphate (APP), in 1:1 proportions, on the flame retardancy behavior and performance of ethylene vinyl acetate copolymer was discussed. Combining APP with partly and completely hydrated calcium oxide led to superior flame‐retardant function detected in mass loss calorimeter measurements with respect to the corresponding system containing carbonated calcium. This privileged character was attributed to the higher reactivity of hydrated Ca‐based fillers toward APP in comparison with Ca carbonate, which induced the formation of an intumescent residue. The difference between reactivity potential of hydrated and dry Ca was demonstrated by the newly formed thermally stable species, and further evidenced by thermogravimetric analysis performed on APP/fillers blends. Moreover, the presence of more crystalline domains in the Ca/phosphorus‐based compounds was evidenced by XRD analysis of the mass loss calorimeter test residues. The results of this work highlight the role of blend additive systems on the performance of flame retardancy of polymer materials.

Optimization of Anguilla bicolor oxygen consumption in alkalinity culture media

One potential aquaculture commodity that can be developed is Anguilla bicolor. One effort that can be conducted to maximize the life and growth of A. bicolor by manipulating water quality through alkalinity parameters. Alkalinity is a buffer capacity for changing in water pH, and osmotic pressure of water. Alkalinity levelss in culture media can be managed by the addition of calcium carbonate (CaCO3), calcium oxide (CaO), or calcium hydroxide (CaOH) with a certain dose to the culture media. This study aimed to determine the effect of alkalinity on aquaculture media based on the level of oxygen consumption (OC) that related to growth value. This research was conducted with an experimental design using a completely randomized design (CRD) with four treatments, namely the addition of CaCO3 to maintenance media with different doses (A, 0 mg/L; B, 50 mg/L; C, 100 mg/L; D, 150 mg/L). The results showed that the treatment B (50 mg / L) showed an OC value (0.15 mgO2/g/h) and an optimal Growth Rate (GR) (3.75 g/day), while the Survival Rate (SR) parameter, the treatment had no significant effect. The conclusion was 50 mg/L of calcium carbonate (CaCO3) having the optimum alkalinity level in A. bicolor culture media. At the additional dose of CaCO3, the growth value (GR), and the level of eel fish oxygen consumption were optimal.

Improving the biocatalytic performance of co-immobilized cells harboring nitrilase via addition of silica and calcium carbonate.

To improve nicotinic acid (NA) yield and meet industrial application requirements of sodium alginate-polyvinyl alcohol (SA-PVA) immobilized cells of Pseudomonas putida mut-D3 harboring nitrilase, inorganic materials were added to the SA-PVA immobilized cells to improve mechanical strength and mass transfer performance. The concentrations of inorganic materials were optimized to be 2.0% silica and 0.6% CaCO3. The optimal pH and temperature for SA-PVA immobilized cells and composite immobilized cells were both 8.0 and 45°C, respectively. The half-lives of composite immobilized cells were 271.48, 150.92, 92.92 and 33.12h, which were 1.40-, 1.35-, 1.22- and 1.63-fold compared to SA-PVA immobilized cells, respectively. The storage stability of the composite immobilized cells was slightly increased. The composite immobilized cells could convert 14 batches of 3-cyanopyridine with feeding concentration of 250mM and accumulate 418g·L-1 nicotinic acid, while the SA-PVA immobilized cells accumulated 346gL-1 nicotinic acid.

Evaluation of the influence of calcium carbonate on the firing process and sintering time

This paper presents the use of calcium carbonate as an additive in the manufacturing process of ceramic bricks, in order to reduce the temperature and sintering time of the clays and to improve the quality of the products. In the study, samples of solid bricks with two different proportions were made. One was composed of 100% clay and the other of 70% clay and 30% calcium carbonate, which were fired in an intermittent kiln. The temperatures of the firing process were recorded using a virtual instrument. The samples manufactured were tested for water absorption and strength. The addition of calcium carbonate brought advantages such as an 8.66% decrease in fuel consumption, a 23.88% decrease in firing time, a 12.11% and 26.67% decrease in the firing temperature and gases released into the environment, respectively, as well as improvements in the quality of the product. The use of calcium carbonate as an additive decreased the time and temperature of ceramic firing and fuel consumption and increased energy efficiency, productivity and product quality, as well as reduced gas emissions into the environment.

Sustainable Micro and Nano Additives for Controlling the Migration of a Biobased Plasticizer from PLA-Based Flexible Films.

Plasticized poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blend-based films containing chitin nanofibrils (CN) and calcium carbonate were prepared by extrusion and compression molding. On the basis of previous studies, processability was controlled by the use of a few percent of a commercial acrylic copolymer acting as melt strength enhancer and calcium carbonate. Furthermore, acetyl n-tributyl citrate (ATBC), a renewable and biodegradable plasticizer (notoriously adopted in PLA based products) was added to facilitate not only the processability but also to increase the mechanical flexibility and toughness. However, during the storage of these films, a partial loss of plasticizer was observed. The consequence of this is not only correlated to the change of the mechanical properties making the films more rigid but also to the crystallization and development of surficial oiliness. The effect of the addition of calcium carbonate (nanometric and micrometric) and natural nanofibers (chitin nanofibrils) to reduce/control the plasticizer migration was investigated. The prediction of plasticizer migration from the films’ core to the external surface was carried out and the diffusion coefficients, obtained by regression of the experimental migration data plotted as the square root of time, were evaluated for different blends compositions. The results of the diffusion coefficients, obtained thanks to migration tests, showed that the CN can slow the plasticizer migration. However, the best result was achieved with micrometric calcium carbonate while nanometric calcium carbonate results were less effective due to favoring of some bio polyesters’ chain scission. The use of both micrometric calcium carbonate and CN was counterproductive due to the agglomeration phenomena that were observed.

The Role of Population and Half-Sib Family on Driving Suitable Functional Traits for Quercus suber L. Forest Restoration

Research Highlights: Seedlings of different Quercus suber L. populations and half-sib families differ in their response to multiple stressors, which may have consequences on the future distribution of this Mediterranean species. Background and Objectives: Global change will likely increase the frequency and severity of drought in drylands. Plant species’ distributions will largely depend on their ability to respond to the combined effect of drought and other environmental stressors. Genetic diversity in morpho-functional traits are key components of this response. Yet, information on the response to multiple stresses is scarce for many iconic species. The present study assessed the variability in the response of populations and half-sib families of a Mediterranean acidophilous tree, cork oak, to drought and changes in soil conditions. Materials and Methods: We sampled acorns of half-sib families from two cork oak populations genetically introgressed with the alkaline-tolerant species Quercus ilex L., and from a non-introgressed cork oak population located in its core habitat. We germinated the acorns and subjected seedlings to contrasted levels of water availability and additions of calcium and magnesium carbonate, and assessed their morpho-physiological response. Results: Response to drought and soil chemistry composition differed between populations and families. For some traits, introgressed populations responded similarly to drought than the non-introgressed population. Conversely, the response to soil chemistry was not clearly related to introgression. When considering half-sib families within populations, the population effect diminished, which revealed the importance of intra-population variation. However, relevant traits for water scarcity adaptations, such as specific leaf area and root:shoot ratio, remained significantly different at the population level, which highlights the relevance of these traits for management. Conclusions: Our study shows that the adaptive management and restoration of cork oak forests should consider not only geographic provenances, but also half-sib lines within populations.

The Effects of Using Different Levels of Calcium Carbonate (CaCO3) on Growth, Survival, Molting Frequency and Body Composıtion of Freshwater Crayfısh Juvenile, Pontastacus leptodactylus (Eschscholtz, 1823)

The present study was conducted to determine different calcium carbonate (CaCO3) level effects on growth, survival, molting frequency and body composition of freshwater crayfish juvenile, Pontastacus leptodactylus (Eschscholtz, 1823). Initial mean weight and length juvenile crayfish were measured to be 0.53±0.01 g and 22.0±0.05 mm, respectively. Crayfish were stocked randomly in twelve aquariums in area of 0.2 m2 at the rate of 50 crayfish/m2. The different level of CaCO3 was added into a commercial trout diet (Control), 3%, 6% and 12% for feeding the juvenile crayfish. After 90-day study, supplementation of CaCO3 significantly (P< 0.05) did affect growth rate, specific growth rate, feed intake, molting frequency, biomass, but reduced survival of crayfish at level of 6% diet as compared to the other groups. The proximate composition of tail meat of crayfish was unaffected by the diet. These results indicated that the calcium carbonate addition is required for crayfish. At the end of the experiment, 6% of calcium carbonate was suggested to be used in formulated diets for crayfish juvenile.

Improved permeation, separation and antifouling performance of customized polyacrylonitrile ultrafiltration membranes

Tailored polyacrylonitrile (PAN) ultrafiltration (UF) membranes are fabricated with Pluronic-F127 and polyethylene glycol phosphate decorated calcium carbonate (PGP-CaCO3) additives with the aim of high water permeation, macromolecular rejection and antifouling properties. The nanoscale CaCO3 synthesis is carried out via a single step carbonization route using PGP as a hydrophilic modifier to introduce hydroxyl groups onto its surface. The topographies of the nanoparticles are investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). PAN/PGP-CaCO3 mixed matrix membranes (MMMs) are fabricated via phase inversion method and examined by attenuated total reflectance-Fourier infra-red spectroscopy (ATR-FTIR), mechanical stability, thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM) to explore the changes in membrane properties due to the well-dispersed PGP-CaCO3 in the PAN membrane matrix. The UF performance of the membranes is investigated in terms of pure water flux, macromolecular rejection and antifouling property. The fouling resistance of membranes is assessed using bovine serum albumin (BSA) and humic acid (HA) as model foulants. The membrane loaded with 0.75wt.% (M3) of PGP-CaCO3 manifested increased wettability with reduced surface free energy leading to a higher pure water flux of 366L/m2h. M3 also displayed a rejection of 93.9% for BSA and 93.2% for HA. The success of the modification can be confirmed as the membrane M3 exhibited lower flux decline and displayed a flux recovery ratio of 90.98% during HA filtration. The results demonstrated the potential use of PAN/PGP-CaCO3 membranes in water treatment.

Calcium Carbonate Addition Improves L-Methionine Biosynthesis by Metabolically Engineered Escherichia coli W3110-BL.

L-Methionine (L-Met) is a sulfur-containing amino acid, which is one of the eight essential amino acids to human body. In this work, the fermentative production of L-Met with genetically engineered Escherichia coli W3110-BL in a 5-L fermentor was enhanced through supplement of Ca2+ into the fermentation medium. With the addition of 30 g/L calcium carbonate (CaCO3), the titer of L-Met and yield against glucose reached 1.48 g/L and 0.09 mol/mol glucose, 57.45% higher than those of the control, respectively. The flux balance analysis (FBA) revealed that addition of CaCO3 strengthened the tricarboxylic acid cycle and increased the intracellular ATP concentration by 39.28%. The re-distribution of carbon, ATP, and cofactors flux may collaborate to improve L-Met biosynthesis with E. coli W3110-BL. The regulation of citrate synthase and oxidative phosphorylation pathway was proposed to be important for overproduction of L-Met. These foundations provide helpful reference in the following metabolic modification or fermentation control for further improvement of L-Met biosynthesis.

Forced flowering of pineapple (Ananas comosus cv. Tainon 16) in response to ethephon with or without calcium carbonate

As a gaseous plant hormone, ethylene is responsible for inducing the initiation of reproductive development in pineapple. Reproductive development can be forced in pineapple (Ananas comosus) throughout the year with ethylene. Ethephon is the most common agent applied in pineapple forcing with high uniformity and convenience. We studied the effect of additive added to the ethephon solution on the plant and fruit of pineapple. Shoot apices of pineapple treated twice to evaluate the effect. Results showed that t 800mg/L ethephon could induce flowering successfully, addition of calcium carbonate could reduce the dose of ethephon significantly from 800 to 50. Furthermore, the addition of calcium carbonate not only caused the prolongation of the peduncle and increasing of slip number, but also increased fruilet numbers and fruit weight with a highly significant difference. 100mg/L ethephon with 0.04% calcium carbonate was the optimum forcing treatment for Tainon 16 cultivar.

Additive manufacturing of Portland cement pastes with additions of kaolin, superplastificant and calcium carbonate

The aim of this investigation is to develop inexpensive formulations of Portland cement pastes for use in additive manufacturing with the direct ink writing technique. Kaolin, a superplastificant based on cellulose, and calcium carbonate were used as additives and modifiers of printing quality. A total of 15 formulations were created for the printing process, of which 3 were able to produce printed parts with the right shape, stability and finish. Cylindrical samples of 17 mm in diameter and 26 mm in height were created for compression testing. Parts with complex geometries were also printed in order to evaluate the versatility of the formulations in the process. The microstructure was characterized with scanning electron microscopy and X-ray diffraction. Mass flow through the nozzle and density were measured and Weibull distribution graphs were plotted. The results showed that the best formulation was mainly associated to an optimal kaolin content, which functioned as a rheology regulator. Water absorption tests showed that the printed samples were porous materials, which would make them suitable for use in many applications.

Zinc and Calcium Cations Combination in the Production of Floating Alginate Beads as Prednisolone Delivery Systems.

The aim of this research was to verify the application of alginate in combination with Ca2+ and Zn2+ ions to produce a floating and prolonged release system for the oral administration of prednisolone. Hollow and floating gel-beads were designed using prilling/ionotropic gelation as the microencapsulation technique, zinc acetate in the gelling solution as the alginate external crosslinker, and calcium carbonate in the feed as the internal crosslinking agent able to generate gas when in contact with the acidic zinc acetate solution. To achieve this goal, drug/alginate solutions were opportunely combined with different amounts of calcium carbonate. The effect of the addition of calcium carbonate into the feed solution on buoyancy, encapsulation efficiency, morphology, size distribution, as well as in vitro drug release profile of the alginate particles was studied. Moreover, the ability of the floating beads to modulate in vivo the anti-inflammatory response was assayed using the carrageenan-induced acute oedema in rat paw. The proposed strategy allowed obtaining alginate beads with extremely high encapsulation efficiency values (up to 94%) and a very porous inner matrix conferring buoyancy in vitro in simulated gastric fluid up to 5 h. Moreover, in vivo, the best formulation, F4, resulted in the ability to prolong the anti-inflammatory effect up to 15 h compared with raw prednisolone.

Gasification of Torrefied Sewage Sludge With the Addition of Calcium Carbonate

Abstract Utilization of sewage sludge, in a way friendly to the environment, is still a subject of intensive investigation. One of the possible solutions is the gasification of sewage sludge. Torrefaction and the use of additive can enhance this process. This study presents the results of the gasification of raw and mildly torrefied sewage sludge, as well as mildly torrefied sewage sludge with the addition of calcium carbonate. Overall, the torrefaction in mild conditions had little influence on the composition of the obtained gas. The influence was much more visible when 5% of calcium carbonate was added. The additive caused the increased average concentration of CH4 and decreased average concentration of H2 in the producer gas. The use of additive also improved the kinetics of the gasification of torrefied sewage sludge. Moreover, the tar deposition diagram confirmed that the use of calcium carbonate enhanced the quality of the produced gas by decreasing the content of the compounds, with a melting point higher than 30 °C, thus minimizing the deposition problem.

Effect of functional mineral additive on processability and material properties of wood-fiber reinforced poly(lactic acid) (PLA) composites

This study examines the use of alkenyl succinic anhydride (ASA)-surface treated calcium carbonate as a functional mineral additive for application in wood fiber (WF)-reinforced PLA composites. The influence of addition quantity on the material properties of PLA composites with 40 wt% fiber reinforcement was examined at mineral addition levels of 10 wt%, 20 wt% and 30 wt%, respectively. The benefits of ASA surface-treated calcium carbonate over untreated mineral were exemplified by comparing the thermomechanical properties of PLA composites at an addition level of 10 wt%.The results demonstrate that the addition of ASA-treated calcium carbonate has distinctive advantages over untreated mineral, in terms of both processability and material properties. First, it enables better control of the process by reducing the flowability of the PLA matrix. Furthermore, it improves the fiber adhesion with the PLA, allowing for a substantial reduction of PLA content in the composite formulation while maintaining material properties.

Emissions of gaseous pollutants, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzo-furans from medical waste combustion in a batch fluidized-bed incinerator

The quantities of pollutants emitted during the incineration of medical waste using a batch fluidized-bed system have not yet been well characterized. In this study, the CO, NO, and SO2 in the gaseous emissions of a pilot scale vortexing fluidized-bed incinerator (VFBI) and the toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans (PCDD/Fs) in the fly ash collected from the baghouse were examined. Four kinds of simulated medical wastes with different chlorine contents were used. The effects of the feeding interval, chlorine content, and the addition of calcium carbonate were experimentally evaluated. The results showed that increasing the feeding interval decreased the amount of all pollutants due to the decreased bed temperature and prolonged residence time in the incinerator. The addition of calcium carbonate decreased the emissions of the three gaseous pollutants; however, the concentrations of PCDD/Fs of the fly ash increased while calcium carbonate was added. The concentration of NO and SO2 decreased while CO concentration increased with the increasing of chlorine content in the simulated medical waste. The magnitude of the effects of the operating parameters on the PCDD/F congeners formed followed the order: chlorine content > feeding interval > Ca/Cl ratio. Based on the experimental results, we extrapolate that the threshold value of the chlorine content was about 1% for PCDD/Fs generation. At a lower chlorine content, the PCDDs formation rate is higher than that at a higher chlorine content, especially for 1,2,3,4,6,7,8-HpCDD and OCDD. When the chlorine content exceeds the threshold value of 1%, the formation rate of PCDFs exceeds that of PCDDs.

Effective removal of fluoride and phosphate pollution using mixtures of dicalcium phosphate dihydrate (DCPD) and Tunisian reservoir sediment containing calcium carbonate

The removal of fluoride from environmental surface water and groundwater is an important environmental issue in Tunisia. Notably, Tunisia also faces a shortfall in reservoir capacity due to the buildup of sediment containing calcium carbonate. Dicalcium phosphate dihydrate (DCPD, CaHPO4·2H2O) reacts effectively with fluoride to form stable fluorapatite (FAp, Ca10(PO4)6F2), and the addition of calcium carbonate (CaCO3) effectively inhibits the release of phosphate generated during this reaction. In this study, we tested the potential for fluoride removal using a mixture of DCPD and Tunisian reservoir sediment. The release of phosphate from the reaction of DCPD with fluoride was successfully inhibited using the sediment. The application of the DCPD–sediment mixture led to a high rate of fluoride removal (15–19 mg/g), such that the resulting water met the World Health Organization (WHO) recommended limit for fluoride in water (1.5 mg/L). This removal rate is five to ten times those achieved with conventional fluoride adsorbents such as bone char. Based on these results, the utilization of Tunisian reservoir sediment seems to be an effective solution for removing fluoride from aqueous environments.

Effect of Calcium Carbonate on the Mechanical Properties and Microstructure of Red Clay

The influence of precipitated calcium carbonate on the strength and microstructure of red clay was studied. Precipitated calcium carbonate was added to red clay at ratios of 0%, 5%, 10%, 15%, and 20%. Shear tests were carried out on the samples to observe the effect of calcium carbonate on the mechanical properties of red clay. The results showed that, with increasing calcium carbonate content, the strength of red clay first decreased and then increased. The maximum strength was obtained for the sample with 20% calcium carbonate. Scanning electron microscopy (SEM) was used to observe the changes in microstructure caused by addition of calcium carbonate. The pores and cracks analysis system (PCAS) was used to quantitatively characterize the microstructure changes detected in SEM images. The addition of calcium carbonate decreased the pore area and increased the total number of pores of red clay. The incorporation of calcium carbonate caused the red clay particles to agglomerate. The higher the calcium carbonate content, the stronger the agglomeration of red clay particles in the soil samples.

Influence of different culture conditions on exopolysaccharide production by indigenous lactic acid bacteria isolated from pickles.

The objective of this study was to assess the effects of some culture conditions [temperature (20, 30, 37°C), incubation time (48, 72, 120h), pH (5.0, 6.0, 7.0), NaCl concentration (0, 3, 6%), carbon (glucose, fructose, lactose), nitrogen (sodium nitrate, ammonium sulfate, bacto-peptone), and mineral sources (calcium carbonate, ferric chloride)] on the exopolysaccharide (EPS) production by lactic acid bacteria (LAB) strains (belonging to Lactobacillus (L.) plantarum, L. namurensis, and Pediococcus (P.) ethanolidurans species) isolated from naturally fermented pickles. The maximum EPS production was determined at 30°C and pH 6.0. The highest amount of EPS was obtained after 120h of incubation, with glucose as carbon source, bacto-peptone as nitrogen source and calcium carbonate as mineral source for most of the tested strains. The EPS formation was not stimulated by NaCl, indicating that EPS formation of the tested strains was not a stress response. L. plantarum MF460 produced the highest amount of EPS at 30°C after 48h of incubation, which was 515.48mg/L. One of the most pronounced results of this study was that the EPS production of L. plantarum MF556 strain was increased up to 512.81mg/L with the addition of calcium carbonate to MRS medium. The effect of different culture conditions, particularly of incubation time, carbon, nitrogen, and mineral sources, on the EPS production often vary depending on the strain. Therefore, these apparent strain specific results demonstrated that the optimum culture conditions for the enhanced EPS production should be specifically determined for each LAB strain.

Coal and Coke Based Reduction of Vanadium Titanomagenetite Concentrate by the Addition of Calcium Carbonate

ABSTRACT Effects of different coals and coke on the direct reduction of vanadium titanomagnetite concentrate (VTC) added with calcium carbonate were investigated. Lignite was found to provide a better reduction effect than bituminous coal, coke or anthracite, mainly because the gasification reactivity of lignite was obviously better than that of other three reductants, and the metallization degree could reach 95.11 wt% when used lignite. Coals and coke showed little influence on the existence form of Ti in the reduction product, where Ti existed mainly as calcium titanate. Additionally, lignite, coke or anthracite all promoted the growth of metallic iron and calcium titanate particles batter than bituminous coal, which were conducive to subsequent magnetic separation. However, the use of coke or anthracite gave lower purity calcium titanate because of the existence of unreduced iron. Furthermore, these reductants caused large amounts of FeS around metallic iron particles, which hindered the further reduction of iron.