CaCO3 Deposits Research Articles

Preparation of fluorescent polyaspartic acid and evaluation of its scale inhibition for CaCO3 and CaSO4

Polysuccinimide was synthesized from maleic anhydride and urea. A polyaspartic acid derivative (PASP‐Try‐SEA) was synthesized from the polysuccinimide with 2‐aminoethanesulfonic acid and tryptophan. The products were characterized by UV, FTIR,1H NMR, TGA and PL, respectively. The results showed that the fluorescent chromophore‐indolyl groups were successfully incorporated into PASP. The relationship between the fluorescence intensity and the concentration of fluorescent polyaspartic acid (FPASP) is linear with the excitation wavelength of 366 nm and 422 nm. FPASP also showed excellent scale inhibition properties with a scale inhibition rate of 78% achieved for CaCO3 with a dosage of 9 mg/L and a significantly enhanced scale inhibition effect for CaSO4, achieving an inhibition rate of 98%, which were determined using the static scale inhibition method. When FPASP was added to the solution, CaCO3 and CaSO4 deposits showed flower patterns with floppy accumulation by scanning electron microscopy. Copyright © 2016 John Wiley & Sons, Ltd.

Influence of the Scaling Inhibitor on the Phase Composition, Morphology, and Sedimentation Properties of CaCO3 Deposits

We study the influence of OK-2 scaling inhibitor based on polyhexamethyleneguanidine hydrochloride on the morphology and phase composition of calcium carbonate. It is established that the presence of inhibitor in the solution leads to an increase in the sizes of crystals in the deposit and the predominance of needle structures in it. The aragonite and calcite phases are in excess in the deposits of calcium carbonate and the presence of inhibitor in the solution increases the amount of calcite by 21%. The revealed effects are caused by the adsorption of the inhibitor on carbonate deposits, which can be described by the Langmuir isotherm. The adsorption of the inhibitor leads to the recharging of the CaCO3 surface and to the increase in the size of particles of the dispersed phase, which promotes its faster precipitation.

Ultrasonic assisted direct contact membrane distillation hybrid process for membrane scaling mitigation

A novel ultrasonic assisted direct contact membrane distillation hybrid process was designed and the effect of ultrasonic irradiation on membrane scaling mitigation during membrane distillation process was investigated. Under ultrasonic irradiation, ultrasonic wave refreshed the liquid-membrane interface continuously and reduced concentration polarization in the boundary layer adjacent to membrane surface simultaneously. Therefore, ultrasonic irradiation could mitigate membrane scaling caused by CaSO4 and prevented the permeate flux decline. Although the ultrasonic irradiation could restrain the crystal size of CaCO3 deposits and clean membrane surface, the experimental results demonstrated that it was not necessary to introduce ultrasonic irradiation into membrane distillation process for CaCO3 membrane scaling mitigation. Due to fast precipitation rate, the concentration of CaCO3 solution would not cause notable permeate flux decline in the absence of ultrasonic irradiation. There would be a gradual permeate flux decline during the concentration process of silica solution because of the formation and deposition of colloidal polysilicic acid on membrane surface. The ultrasonic irradiation caused the zeta potential of silica colloids to approach neutral and enhanced the tendency of colloid deposit, but the membrane surface could be effectively kept clean and the permeate flux was hardly affected by concentration factor increasing.

Morphology, microstructure, crystallography, and chemistry of distinct CaCO3 deposits formed by early recruits of the scleractinian coral Pocillopora damicornis.

Scleractinian corals begin their biomineralization process shortly after larval settlement with the formation of calcium carbonate (CaCO(3)) structures at the interface between the larval tissues and the substrate. The newly settled larvae exert variable degrees of control over this skeleton formation, providing an opportunity to study a range of biocarbonate structures, some of which are transient and not observed in adult coral skeletons. Here we present a morphological, structural, crystallographic, and chemical comparison between two types of aragonite deposits observed during the skeletal development of 2-days old recruits of Pocillopora damicornis: (1) Primary septum and (2) Abundant, dumbbell-like structures, quasi-randomly distributed between initial deposits of the basal plate and not present in adult corals-At the mesoscale level, initial septa structures are formed by superimposed fan-shaped fasciculi consisting of bundles of fibers, as also observed in adult corals. This organization is not observed in the dumbbell-like structures. However, at the ultrastructural level there is great similarity between septa and dumbbell components. Both are composed of <100 nm granular units arranged into larger single-crystal domains.Chemically, a small difference is observed between the septae with an average Mg/Ca ratio around 11 mmol/mol and the dumbbell-like structures with ca. 7 mmol/mol; Sr/Ca ratios are similar in the two structures at around 8 mmol/mol-Overall, the observed differences in distribution, morphology, and chemistry between septa, which are highly conserved structures fundamental to the architecture of the skeleton, and the transient, dumbbell-like structures, suggest that the latter might be formed through less controlled biomineralization processes. Our observations emphasize the inherent difficulties involved in distinguishing different biomineralization pathways based on ultrastructural and crystallographical observations.

Characterization of corrosion products formed on different surfaces of steel exposed to simulated groundwater solution

The corrosion behavior of a low alloy steel in simulated groundwater was investigated. The upward surface of the steel underwent more serious corrosion than the downward surface. The corrosion products formed on the upward and downward surfaces were characterized by SEM, EDX, and XRD, and the electrochemical properties of bare and rusted samples were analyzed. The difference in the corrosion rates of the different surfaces of the steel could be attributed to the potential difference between the upward and downward surfaces as well as the higher amount of CaCO3 deposits on the downward surface leading to a compact corrosion product.

Preparation and properties of β-cyclodextrins polymer used as calcium carbonate scale inhibitor containing fluorescent groups

In an attempt to control CaCO3 deposits in industrial recycling water systems, a maleic anhydride-β-cyclodextrins-acrylic acid-8-hydroxy-1, 3, 6-pyrenetrisulfonic acid trisodium salt (MA–β-CD–AA–PA) copolymer was synthesized by free-radical polymerization. The structure of the copolymer was characterized using FT-IR, 1H NMR, and TGA. The MA–β-CD–AA–PA exhibited an excellent ability to control inorganic minerals, with 95.8 % CaCO3 inhibition at level of 10 mg l−1 MA–β-CD–AA–PA, which suggested that the prepared copolymer was an excellent scale inhibitor. The copolymer showed the same fluorescence as pyranine. The fluorescence intensity of the copolymer was directly proportional to its concentration.

Biomineralization in newly settled recruits of the scleractinian coral Pocillopora damicornis.

Calcium carbonate biomineralization of scleractinian coral recruits is fundamental to the construction of reefs and their survival under stress from global and local environmental change. Establishing a baseline for how normal, healthy coral recruits initiate skeletal formation is, therefore, warranted. Here, we present a thorough, multiscale, microscopic and spectroscopic investigation of skeletal elements deposited by Pocillopora damicornis recruits, from 12 h to 22 days after settlement in aquarium on a flat substrate. Six growth stages are defined, primarily based on appearance and morphology of successively deposited skeletal structures, with the following average formation time-scales: A (<24 h), B (24-36 h), C (36-48 h), D (48-72 h), E (72-96 h), and F (>10 days). Raman and energy dispersive X-ray spectroscopy indicate the presence of calcite among the earliest components of the basal plate, which consist of micrometer-sized, rod-shaped crystals with rhomboidal habit. All later CaCO3 skeletal structures are composed exclusively of aragonite. High-resolution scanning electron microscopy reveals that, externally, all CaCO3 deposits consist of <100 nm granular units. Fusiform, dumbbell-like, and semispherulitic structures, 25-35 µm in longest dimension, occur only during the earliest stages (Stages A-C), with morphologies similar to structures formed abiotically or induced by organics in in vitro carbonate crystallization experiments. All other skeletal structures of the basal plate are composed of vertically extending lamellar bundles of granules. From Stage D, straight fibrils, 40-45 nm in width and presumably of organic composition, form bridges between these aragonitic bundles emerging from the growing front of fusing skeletal structures. Our results show a clear evolution in the coral polyp biomineralization process as the carbonate structures develop toward those characterizing the adult skeleton.

Modulation of the Initial Mineralization Process of SaOS-2 Cells by Carbonic Anhydrase Activators and Polyphosphate

Ca-phosphate/hydroxyapatite (HA) crystals constitute the mineral matrix of vertebrate bones, while Ca-carbonate is the predominant mineral of many invertebrates, like mollusks. Recent results suggest that CaCO₃ is also synthesized during early bone formation. We demonstrate that carbonic anhydrase-driven CaCO₃ formation in vitro is activated by organic extracts from the demosponge Suberites domuncula as well as by quinolinic acid, one component isolated from these extracts. Further results revealed that the stimulatory effect of bicarbonate (HCO₃ (-)) ions on mineralization of osteoblast-like SaOS-2 cells is strongly enhanced if the cells are exposed to inorganic polyphosphate (polyP), a linear polymer of phosphate linked by energy-rich phosphodiester bonds. The effect of polyP, administered as polyP (Ca²⁺ salt), on HA formation was found to be amplified by addition of the carbonic anhydrase-activating sponge extract or quinolinic acid. Our results support the assumption that CaCO₃ deposits, acting as bio-seeds for Ca-carbonated phosphate formation, are formed as an intermediate during HA mineralization and that the carbonic anhydrase-mediated formation of those deposits is under a positive-negative feedback control by bone alkaline phosphatase-dependent polyP metabolism, offering new targets for therapy of bone diseases/defects.

Characterization of calcium deposition induced by Synechocystis sp. PCC6803 in BG11 culture medium

Calcium carbonate (CaCO3) crystals in their preferred orientation were obtained in BG11 culture media inoculated with Synechocystis sp. PCC6803 (inoculated BG11). In this study, the features of calcium carbonate deposition were investigated. Inoculated BG11 in different calcium ion concentrations was used for the experimental group, while the BG11 culture medium was used for the control group. The surface morphologies of the calcium carbonate deposits in the experimental and control groups were determined by scanning and transmission electron microscopy. The deposits were analyzed by electronic probe micro-analysis, Fourier transform infrared spectrum, X-ray diffraction, thermal gravimetric analysis and differential scanning calorimetry. The results show that the surfaces of the crystals in the experimental group were hexahedral in a scaly pattern. The particle sizes were micrometer-sized and larger than those in the control group. The deposits of the control group contained calcium (Ca), carbon (C), oxygen (O), phosphorus (P), iron (Fe), copper (Cu), zinc (Zn), and other elements. The deposits in the experimental group contained Ca, C, and O only. The deposits of both groups contained calcite. The thermal decomposition temperature of the deposits in the control group was lower than those in the experimental group. It showed that the CaCO3 deposits of the experimental group had higher thermal stability than those of the control group. This may be due to the secondary metabolites produced by the algae cells, which affect the carbonate crystal structure and result in a close-packed structure. The algae cells that remained after thermal weight loss were heavier in higher calcium concentrations in BG11 culture media. There may be more calcium-containing crystals inside and outside of these cells. These results shall be beneficial for understanding the formation mechanism of carbonate minerals.

Physiologic and metagenomic attributes of the rhodoliths forming the largest CaCO3 bed in the South Atlantic Ocean

Rhodoliths are free-living coralline algae (Rhodophyta, Corallinales) that are ecologically important for the functioning of marine environments. They form extensive beds distributed worldwide, providing a habitat and nursery for benthic organisms and space for fisheries, and are an important source of calcium carbonate. The Abrolhos Bank, off eastern Brazil, harbors the world's largest continuous rhodolith bed (of ∼21,000 km(2)) and has one of the largest marine CaCO3 deposits (producing 25 megatons of CaCO3 per year). Nevertheless, there is a lack of information about the microbial diversity, photosynthetic potential and ecological interactions within the rhodolith holobiont. Herein, we performed an ecophysiologic and metagenomic analysis of the Abrolhos rhodoliths to understand their microbial composition and functional components. Rhodoliths contained a specific microbiome that displayed a significant enrichment in aerobic ammonia-oxidizing betaproteobacteria and dissimilative sulfate-reducing deltaproteobacteria. We also observed a significant contribution of bacterial guilds (that is, photolithoautotrophs, anaerobic heterotrophs, sulfide oxidizers, anoxygenic phototrophs and methanogens) in the rhodolith metagenome, suggested to have important roles in biomineralization. The increased hits in aromatic compounds, fatty acid and secondary metabolism subsystems hint at an important chemically mediated interaction in which a functional job partition among eukaryal, archaeal and bacterial groups allows the rhodolith holobiont to thrive in the global ocean. High rates of photosynthesis were measured for Abrolhos rhodoliths (52.16 μmol carbon m(-2 )s(-1)), allowing the entire Abrolhos rhodolith bed to produce 5.65 × 10(5) tons C per day. This estimate illustrates the great importance of the Abrolhos rhodolith beds for dissolved carbon production in the South Atlantic Ocean.

Mineral Deposition in Bacteria-Filled and Bacteria-Free Calcium Bodies in the Crustacean Hyloniscus riparius (Isopoda: Oniscidea)

Crustacean calcium bodies are epithelial sacs which contain a mineralized matrix. The objectives of this study were to describe the microscopic anatomy of calcium bodies in the terrestrial isopod Hyloniscus riparius and to establish whether they undergo molt-related structural changes. We performed 3D reconstruction of the calcium bodies from paraffin sections and analyzed their structure with light and electron microscopy. In addition, we analyzed the chemical composition of their mineralized matrices with micro-Raman spectroscopy. Two pairs of these organs are present in H. riparius. One pair is filled with bacteria while the other pair is not. In non-molting animals, the bacteria-filled calcium bodies contain apatite crystals and the bacteria-free calcium bodies enclose CaCO3-containing concretions with little organic matrix. During preparation for molt, an additional matrix layer is deposited in both pairs of calcium bodies. In the bacteria-filled calcium bodies it contains a mixture of calcium carbonate and calcium phosphate, whereas only calcium carbonate is present in bacteria-free calcium bodies. After ecdysis, all mineral components in bacteria-free calcium bodies and the additional matrix layer in bacteria-filled calcium bodies are completely resorbed. During calcium resorption, the apical surface of the calcium body epithelium is deeply folded and electron dense granules are present in spaces between epithelial cells. Our results indicate that the presence of bacteria might be linked to calcium phosphate mineralization. Calcium bodies likely provide a source of calcium and potentially phosphate for the mineralization of the new cuticle after molt. Unlike other terrestrial isopods, H. riparius does not form sternal CaCO3 deposits and the bacteria-free calcium bodies might functionally replace them in this species.

Sources and Sinks of Phosphorus for a Perturbed Stream and the Effects of Mineral Deposits1

Effler, Steven W., Anthony R. Prestigiacomo, David A. Matthews, and Feng Peng, 2012. Sources and Sinks of Phosphorus for a Perturbed Stream and the Effects of Mineral Deposits. Journal of the American Water Resources Association (JAWRA) 48(2): 321‐335. DOI: 10.1111/j.1752‐1688.2011.00617.xAbstract: Patterns of concentrations and loading rates of multiple forms of phosphorus (P) are resolved and analyzed along Ninemile Creek, New York, a stream perturbed by a domestic waste discharge and residual effects of a closed industry. This analysis is based on biweekly monitoring of total, dissolved, and soluble reactive P (SRP) for 19 months at four sites that bracket each of these effects, and 15 years of biweekly measurements at the two sites that bound industrial deposits. The minerogenic particle populations of the stream and the surficial sediments along the reach with extensive CaCO3 and clay mineral deposits are characterized with an individual particle analysis technique. Mass balance analyses depict: (1) increasing nonpoint inputs of particulate and dissolved organic P along the stream length; (2) input of P from a domestic waste facility, almost entirely in the form of SRP; and (3) a compensating downstream loss of SRP over the reach with the extensive industrial deposits of CaCO3. The downstream sink process for SRP is attributed to sorption processes with minerogenic deposits. The domestic waste‐based source and the compensating industrial waste‐based sink are noteworthy fluxes relative to other prevailing loads received by downstream Onondaga Lake, for which a major rehabilitation program targeting cultural eutrophication is underway. The P source/sink conditions of this stream are considered in the context of this rehabilitation program.

PENGARUH MEDAN MAGNET TERHADAP PROSES PRESIPITASI CaCO3 DALAM AIR SADAH

Magnetic Field Effects on CaCO3 Precipitation Process in Hard Water. Magnetic treatment is applied as physical water treatment for scale prevention especially CaCO3, from hard water in piping equipment by reducing its hardness. Na2CO3 and CaCl2 solution sample was used in to investigate the magnetic fields influence on the formation of particle of CaCO3. By changing the strength of magnetic fields, exposure time and concentration of samples solution, this study presents quantitative results of total scale deposit, total precipitated CaCO3 and morphology of the deposit. This research was run by comparing magnetically and non-magnetically treated samples. The results showed an increase of deposits formation rate and total number of precipitated CaCO3 of magnetically treated samples. The increase of concentration solution sample will also raised the deposit under magnetic field. Microscope images showed a greater number but smaller size of CaCO3 deposits form in magnetically treated samples, and aggregation during the processes. X-ray diffraction (XRD) analysis showed that magnetically samples were dominated by calcite. But, there was a significant decrease of calcite’s peak intensities from magnetized samples that indicated the decrease of the amount of calcite and an increase of total amorphous of deposits. This result showed that magnetization of hard water leaded to the decreasing of ion Ca2+ due to the increasing of total CaCO3 precipitation process.

Microbial communities and associated mineral fabrics in Altamira Cave, Spain

Evidences of microbial colonizations were observed in Altamira Cave, Spain. These consisted of distinct small coloured colonies, both on walls and ceiling, mainly located in the area near the cave entrance, which progressed until reaching the Polychromes Hall. The colonizations were characterized by a high morphological and microstructural variability and related to biomineralization processes. Two main types of CaCO3 deposits were related to the colonies: rosetteor nest-like aggregates of rhombohedral calcite crystals, and spheroid to hemispheroid CaCO3 elements. Colonies distribution seems to be controlled by microenvironmental conditions inside the cavity. The areas of the cave showing higher temperature, relative humidity, and CO2 biomineralization capability.

Ultrastructural investigations of sternal CaCO3 deposits of Porcellio scaber (Isopoda, Crustacea) by TEM and STEM-Tomography

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

Technology for preserving surface features of ancient finds in sea water

Archaeological iron objects found in sea water are coated with large amounts of mineralised iron and CaCO3 deposits with the presence of micro and macrobiological components. The aim of the present work is to propose techniques for avoiding detaching of or damage to mineralised iron featured on surface layers and deposits generated by long immersion in a sea-water environment. These elements can actually be the source of important historical information but can be rapidly degraded by successive exposure to the atmosphere. The importance of controlling the pH, redox potentials and osmotic pressure of the solution before the first period of conservation has been pointed out. Moreover, a decrease in surface tension of the liquid phase during drying has been recognised as a critical aspect in avoiding the crack–splitting phenomena of the surface layers. Correct extraction of the chloride through an electrochemical process is fundamental to ensuring the correct storage of finds during successive exposure to the atmosphere. This operation can be implemented by controlling the current density and distribution, thus avoiding development of the gas phase. Technology suitable for performing this operation is described.

Effect of magnetic field on deposition and adhesion of calcium carbonate particles on different substrates

Magnetic field effects on CaCO3 adhesion to substrates were evaluated statistically as for the number of crystals, the occupied surface area per crystal and the crystal size distributions. CaCO3 was precipitated from Na2CO3 and CaCl2 solutions, which prior to precipitation were or were not exposed to a magnetic field under flowing conditions. Glass, copper and stainless steel plates were used as substrates. The precipitation process occurred at 30°C, and in the case of glass plate experiments were also conducted at 60°C. The CaCO3 deposits were photographed using an optical polarizing microscope equipped with a camera and then the images were analyzed statistically. For each system studied 14 plates were used. It was found that in all systems the magnetic field (MF) influenced the number of crystals deposited and their size distribution. The changes were statistically significant (t-Student's test). The nature of the substrate surface was found to have a significant effect on the amount of CaCO3 deposited. However, the average amount of calcium carbonate deposited on the glass surface at 30°C determined from 14 analyzed plates was only slightly less than that from MF-treated solutions (0.689 and 0.748 mg/cm2, respectively), and it was practically the same at 60°C (0.539 and 0.534 mg/cm2). At this higher temperature the deposition of calcium carbonate was reduced relative to that at 30°C. From the results obtained it may be concluded that the MF affects both nucleation and crystal growth of CaCO3.

Hemolymph ion composition and volume changes in the supralittoral isopod Ligia pallasii Brandt, during molt.

We analyzed ion composition and volume of the hemolymph of Ligia pallasii in four different stages of the molt cycle using capillary electrophoresis and 3H-inulin. The main ions in the hemolymph were Na+, K+, Mg2+ , Ca2+, and Cl-. The Ca2+ concentration increased significantly during the molt by 47% from intermolt to intramolt and by 37% from intermolt to postmolt, probably due to resorption of Ca2+ from the cuticle and sternal CaCO3 deposits. The K+ concentration increased significantly by 20% during molt. The hemolymph volume normalized to the dry mass of the animals decreased by 36% from intermolt to late premolt. This was due to a reduction in the hemolymph volume and to an increase in dry mass of the animals during premolt. A sudden increase in the hemolymph volume occurring between late premolt and intramolt served to expand the cuticle. Since the Na+, K+, Mg2+, and Cl- concentrations did not change significantly from late premolt to intramolt, the increase in hemolymph volume suggests an uptake of seawater rather than freshwater.

Membrane Particle Distribution in the Sternal Epithelia of the Terrestrial Isopod Porcellio scaber Latr. (Crustacea, Oniscidea) during CaCO3 Deposit Formation and Resorption, a Freeze-Etch Analysis

The anterior sternal epithelium of terrestrial isopods transports cuticular Ca2+ to and from large sternal CaCO3 deposits. We analyzed the anterior and posterior sternal epithelium by the means of the freeze-etch technique and measured the size distribution and density of intramembrane particles (IMPs) during three different molting stages. At least three IMP size classes around 4.5, 7.7, and 9.4 nm can be distinguished on the P-face of the apical and basolateral plasma membrane. An additional size class of around 12.8 nm is restricted to the apical compartment. In the anterior sternal epithelium, the density of these large particles changes by a factor of 1.9 during the molt cycle, suggesting a role in CaCO3 formation and/or resorption. The density of the smaller IMPs rises transiently by a factor of 1.3 in the posterior sternal epithelium only. The IMP density of the basolateral plasma membrane increases significantly by a factor of 1.4 and 1.3 in the anterior and posterior sternal epithelia, respectively. The results indicate that increases in the IMP density contribute to the differentiation to an increased transport activity during the cyclic enlargements of the plasma membrane surface area in the anterior sternal epithelium.

Electrochemically generated CaCO3 deposits on iron studied with FTIR and Raman spectroscopy

Abstract Calcium carbonate was preferentially electrodeposited onto the relatively high pH surface of an iron electrode held at highly reducing potentials in a CaCl2+NaHCO3 solution. Solution composition, temperature and additives influenced the structure and composition of the calcium carbonate deposit. The conditions that produce the three major crystalline phases (aragonite, vaterite and calcite) along with unstructured phases of calcium carbonate have been identified with FTIR spectroscopy. The use of Raman spectroscopy was also investigated as an in situ detection method for monitoring the calcium carbonate deposition process. The results demonstrate the applicability of an electrochemical method for producing controlled calcium carbonate deposition from solution.