High Inorganic Content Research Articles

Beneficial Effects of Dietary Nitrate on Endothelial Function and Blood Pressure Levels.

Poor eating habits may represent cardiovascular risk factors since high intake of fat and saturated fatty acids contributes to dyslipidemia, obesity, diabetes mellitus, and hypertension. Thus, nutritional interventions are recognized as important strategies for primary prevention of hypertension and as adjuvants to pharmacological therapies to reduce cardiovascular risk. The DASH (Dietary Approach to Stop Hypertension) plan is one of the most effective strategies for the prevention and nonpharmacological management of hypertension. The beneficial effects of DASH diet on blood pressure might be related to the high inorganic nitrate content of some food products included in this meal plan. The beetroot and other food plants considered as nitrate sources account for approximately 60–80% of the daily nitrate exposure in the western population. The increased levels of nitrite by nitrate intake seem to have beneficial effects in many of the physiological and clinical settings. Several clinical trials are being conducted to determine the broad therapeutic potential of increasing the bioavailability of nitrite in human health and disease, including studies related to vascular aging. In conclusion, the dietary inorganic nitrate seems to represent a promising complementary therapy to support hypertension treatment with benefits for cardiovascular health.

Nacre-nanomimetics: Strong, Stiff, and Plastic.

The bricks and mortar in the classic structure of nacre have characteristic geometry, aspect ratios and relative proportions; these key parameters can be retained while scaling down the absolute length scale by more than 1 order of magnitude. The results shed light on fundamental scaling behavior and provide new opportunities for high performance, yet ductile, lightweight nanocomposites. Reproducing the toughening mechanisms of nacre at smaller length scales allows a greater volume of interface per unit volume while simultaneously increasing the intrinsic properties of the inorganic constituents. Layer-by-layer (LbL) assembly of poly(sodium 4-styrenesulfonate) (PSS) polyelectrolyte and well-defined [Mg2Al(OH)6]CO3.nH2O layered double hydroxide (LDH) platelets produces a dense, oriented, high inorganic content (∼90 wt %) nanostructure resembling natural nacre, but at a shorter length scale. The smaller building blocks enable the (self-) assembly of a higher quality nanostructure than conventional mimics, leading to improved mechanical properties, matching those of natural nacre, while allowing for substantial plastic deformation. Both strain hardening and crack deflection mechanisms were observed in situ by scanning electron microscopy (SEM) during nanoindentation. The best properties emerge from an ordered nanostructure, generated using regular platelets, with narrow size dispersion.

Matrix-free Particle Brush System with Bimodal Molecular Weight Distribution Prepared by SI-ATRP

The modification of the surface of nanoparticles with polymeric chains is ubiquitously used to engineer the physicochemical properties of nanoparticle fillers and to enable new material technologies based on polymer hybrid materials with controlled microstructure. The tethering of particles with polymeric chains of distinct (high and low) degree of polymerization (so-called “bimodal polymer grafts”) has emerged as a particularly interesting strategy to combine the synergistic benefits of dense and sparse polymer grafts (i.e., good control of particle interactions facilitated by densely grafted polymer chains with the high inorganic content characteristic for sparsely grafted systems). In this contribution, surface-initiated atom transfer radical polymerization (SI-ATRP) is demonstrated to be a versatile tool that enables the synthesis of bimodal graft modifications with precise control of the degree of polymerization of the respective graft species. For the particular case of polystyrene-tethered silica p...

Removal of introduced inorganic content from chipped forest residues via air classification

Inorganic content in biomass decreases the efficiency of conversion processes, especially thermochemical conversions. The combined concentrations of specific ash forming elements are the primary attributes that cause pine residues to be considered a degraded energy conversion feedstock, as compared to clean pine. Air classification is a potentially effective and economical tool to isolate high inorganic content biomass fractions away from primary feedstock sources to reduce their ash content.In this work, loblolly pine forest residues were air classified into 10 fractions whose ash content and composition were measured. Ash concentrations were highest in the lightest fractions (5.8–8.5wt%), and in a heavy fraction of the fines (8.9–15.1wt%). The removal of fractions with high inorganic content resulted in a substantial reduction in the ash content of the remaining biomass in forest thinnings (1.69–1.07wt%) and logging residues (1.09–0.68wt%). These high inorganic content fractions from both forest residue types represented less than 7.0wt% of the total biomass, yet they contained greater than 40% of the ash content by mass. Elemental analysis of the air classified fractions revealed the lightest fractions were comprised of high concentrations of soil elements (silicon, aluminum, iron, sodium, and titanium).However, the elements of biological origin including calcium, potassium, magnesium, sulfur, manganese, and phosphorous were evenly distributed throughout all air classified fractions, making them more difficult to isolate into fractions with high mineral concentrations. Under the conditions reported in this study, an economic analysis revealed air classification could be used for ash removal for as little as $2.23 per ton of product biomass. This study suggests air classification is a potentially attractive technology for the removal of introduced soil minerals from pine forest residues.

Involvement of Ethylene in the Latex Metabolism and Tapping Panel Dryness of Hevea brasiliensis.

Ethephon, an ethylene releaser, is used to stimulate latex production in Hevea brasiliensis. Ethylene induces many functions in latex cells including the production of reactive oxygen species (ROS). The accumulation of ROS is responsible for the coagulation of rubber particles in latex cells, resulting in the partial or complete stoppage of latex flow. This study set out to assess biochemical and histological changes as well as changes in gene expression in latex and phloem tissues from trees grown under various harvesting systems. The Tapping Panel Dryness (TPD) susceptibility of Hevea clones was found to be related to some biochemical parameters, such as low sucrose and high inorganic phosphorus contents. A high tapping frequency and ethephon stimulation induced early TPD occurrence in a high latex metabolism clone and late occurrence in a low latex metabolism clone. TPD-affected trees had smaller number of laticifer vessels compared to healthy trees, suggesting a modification of cambial activity. The differential transcript abundance was observed for twenty-seven candidate genes related to TPD occurrence in latex and phloem tissues for ROS-scavenging, ethylene biosynthesis and signalling genes. The predicted function for some Ethylene Response Factor genes suggested that these candidate genes should play an important role in regulating susceptibility to TPD.

Characterization of the aqueous fractions from hydrotreatment and hydrothermal liquefaction of lignocellulosic feedstocks

In this study the aqueous phases resulting from the hydrothermal liquefaction (HTL) of biomass and the hydrotreatment (HT) of fast pyrolysis bio-oils were analyzed via TC, COD, GC-MS, GC-FID, HPLC, and ICP-OES to determine the organic and inorganic species present and the quantitative amounts of each. This work is necessary to address a significant knowledge gap in the literature related to the aqueous phases from thermochemical processes. Results showed that water from the hydrotreatment of eight different bio-oils contained less than 1 wt% total carbon, in many cases less than 0.2%. Negligible organic carbon was observed. HTL samples contained between 1 and 2 wt% carbon. Due to the large volume of water added to the HTL feedstock and the dilute samples generated, this accounts for 34–45% of the total carbon sent to the reactor. The majority of this carbon was present as acids, with glycolic acid and acetic acid having the highest concentrations. Alcohols, specifically methanol and ethanol, were also present. Numerous ketones were observed, consisting of mainly acetone and cyclopenta-ones. The amount of the total carbon identified and quantified in the HTL samples ranged from 64 to 82%. Inorganic species present in the HT samples were sodium, silicon, and sulfur. The highest levels of sulfur were observed in the grasses and agricultural residue (corn stover). The HTL samples exhibited much higher inorganic content, with very high levels of sodium and potassium. Alkali and alkali earth metals, as well as sulfur, were also present at levels high enough to raise concerns for the use of catalysts in downstream upgrading or reforming processes.

AFM nanomechanical properties and durability of new hybrid fluorinated sol-gel coatings

Microscopically homogeneous and thin fluorinated hybrid coatings showing significantly high mechanical and photochemical durability are prepared through the sol-gel chemistry and studied in this work. Their physico-chemical and nanomechanical properties are investigated. In this study, a special focus is given to the effects of organic/inorganic ratio and inorganic precursor type on surface and mechanical properties at the nanoscale. Different coatings containing low and high contents of silica as well as a mixed oxide composed of high amount of titania and low amount of silica are investigated. Nanoscratch and nanoindentation tests are performed by atomic force microscopy (AFM) and employed to assess the nanomechanical behavior of the hybrid coatings at a proper scale. Dynamic hardness results obtained from AFM are found to be in good agreement with technological pencil scratch tests performed at a macroscopic scale. Owing to the high inorganic content and good cross-linking degree achieved, coatings with a high amount of silica show considerably high dynamic hardness (nearly 2GPa), which remains unchanged even after a long-term UV-vis light exposure. Notwithstanding the comparable inorganic amount, the hardness of mixed oxide coatings is markedly lower than high silica coatings and is subjected to modifications when exposed to UV-vis light in the long term, as also corroborated by x-ray photoelectron spectroscopy (XPS). Young's modulus results obtained by AFM nanoindentations appear to be dependent mostly on the inorganic/organic ratio. Higher moduli are determined for samples with higher inorganic/organic ratio, and no particular effect of the nature of inorganic precursor upon such property is observed.

Strong and moldable cellulose magnets with high ferrite nanoparticle content.

A major limitation in the development of highly functional hybrid nanocomposites is brittleness and low tensile strength at high inorganic nanoparticle content. Herein, cellulose nanofibers were extracted from wood and individually decorated with cobalt-ferrite nanoparticles and then for the first time molded at low temperature (<120 °C) into magnetic nanocomposites with up to 93 wt % inorganic content. The material structure was characterized by TEM and FE-SEM and mechanically tested as compression molded samples. The obtained porous magnetic sheets were further impregnated with a thermosetting epoxy resin, which improved the load-bearing functions of ferrite and cellulose material. A nanocomposite with 70 wt % ferrite, 20 wt % cellulose nanofibers, and 10 wt % epoxy showed a modulus of 12.6 GPa, a tensile strength of 97 MPa, and a strain at failure of ca. 4%. Magnetic characterization was performed in a vibrating sample magnetometer, which showed that the coercivity was unaffected and that the saturation magnetization was in proportion with the ferrite content. The used ferrite, CoFe2O4, is a magnetically hard material, demonstrated by that the composite material behaved as a traditional permanent magnet. The presented processing route is easily adaptable to prepare millimeter-thick and moldable magnetic objects. This suggests that the processing method has the potential to be scaled-up for industrial use for the preparation of a new subcategory of magnetic, low-cost, and moldable objects based on cellulose nanofibers.

Supercritical water oxidation with hydrothermal flame as internal heat source: Efficient and clean energy production from waste

Supercritical water oxidation (SCWO) has the potential to be considered a clean energy generation process, as the process effluent is a high temperature, high pressure stream with a high enthalpy content that can be converted to heat and shaft work. In this work the state of the art of SCWO has been reviewed, focusing on energy production. For the description of thermodynamic and transport properties, there are some methods recommended for pure substances, but the applicability of those methods for mixtures at supercritical state is yet not clear. Most of the work found in literature use cubic equations of state and linear mixing rules. The design of reactors has evolved in order to reduce the drawbacks of corrosion and salt deposition, in general, through the dilution of reaction products. In order to make the process profitable energetically different strategies must be used to keep the products at the highest temperature without compromising the safety, and the hydrothermal flames if correctly stabilized are a good choice. Reactors and reaction systems able to process feeds consisting of suspension with high inorganic contents without diluting the effluent reducing its temperature must be developed. On the other hand, the systems of energy recovery must be improved, especially the expanders, in order to recover the pressure work as well as the thermal energy. Modeling tools can help in both aspects. But for developing good models a good comprehension of thermal and transport properties of mixtures at supercritical state, as well as oxidation kinetics under that condition are essential data that must be further investigated in order to find energetically efficient processes.

Physicochemical Behavior of Tetracycline and 17α-Ethinylestradiol with Wastewater Sludge-Derived Humic Substances

Sorption–desorption behavior of the antibiotic tetracycline (TET) and the synthetic estrogen hormone 17α-ethinylestradiol (EE2) with wastewater sludge and sludge-derived humic substances [humic acid (HA) and humin] was investigated. From acidic functional group capacity and elemental analyses, HA had higher polarity, aromaticity, and acidity than humin; humin contained aliphatic chains with high mineral content. The different physicochemical properties of the pharmaceuticals and sludge components yielded different kinds of sorption–desorption interactions. Partitioning coefficients (K d) of TET to sludge were higher (1,552 ± 41–4,667 ± 41 L/kg) than EE2 (534 ± 52–609 ± 47 L/kg). TET sorption was highly pH-dependent and maximal at pH 9. Ca2+ ions enhanced sorption, emphasizing the role of polyvalent metal ions in forming TET–sludge complexes. Humin was the dominant component for TET sorption due to its high inorganic matter content. In contrast, EE2 sorption was independent of solution pH, forming mostly hydrophobic interactions with sludge organic matter. EE2 had a high affinity for HA due to its chemical structure. Desorption of the two pharmaceuticals differed as well. The amount of desorbed TET (18.7 ± 1.3–29.8 ± 2 %) was lower than that of EE2 (60.6 ± 3–62.3 ± 2 %), and the hysteresis index was higher for TET than EE2. While TET desorption tended to be delayed in the solid matrix, EE2 desorbed easily and in accordance with the aqueous equilibrium concentration. The conclusions emphasize the need for further research into frequently used pharmaceuticals with different physicochemical properties and the recognition of sludge application as an important source of distribution for these contaminants in the environment.

Periodic nanostructures imprinted on high-temperature stable sol–gel films by ultraviolet-based nanoimprint lithography for photovoltaic and photonic applications

Nanostructured sol–gel films with high-temperature stability are used in the area of electronics, photonics or biomimetic materials as light-trapping architectures in solar cells, displays, waveguides or as superhydrophobic surfaces with a lotus effect. In this work, high-temperature stable 2-μm nanostructured surfaces were prepared by ultraviolet-based nanoimprint lithography using an alkoxysilane binder incorporating modified silica nanoparticles. Material densification during thermal curing and microstructural evolution which are destined for a high structural fidelity of nanostructured films were investigated in relation to precursor chemistry, particle morphology and particle content of the imprint resist. The mechanism for densification and shrinkage of the films was clarified and correlated with the structural fidelity to explain the influence of the geometrical design on the optical properties. A high internal coherence of the microstructure of the nanostructured films results in a critical film thickness of >5μm. The structured glassy layers with high inorganic content show thermal stability up to 800°C and have a high structural fidelity >90% with an axial shrinkage of 16% and a horizontal shrinkage of 1%.This material allows the realization of highly effective light-trapping architectures for polycrystalline silicon thin-film solar cells on glass but also for the preparation of 2D photonic crystals for telecommunication wavelengths.

Intrinsic activation: The relationship between biomass inorganic content and porosity formation during pyrolysis

The utility of pyrolytic carbons is closely related to their porosity and surface area, there is a clear benefit to the development of biomass pyrolysis processes which produce highly porous carbons. The results presented in this work demonstrate that by using biomass precursors with high inorganic content along with specified process conditions, carbons can be consistently produced with specific surface areas between 900 and 1600 m(2)/g. Results from 12 different source materials show that the formation of increased porosity in pyrolytic carbons is strongly associated with the presence of inorganic elements in the precursors including: magnesium, potassium and sulfur. It was found that pyrolysis of macro-algae can produce especially high specific surface area carbons (mean: 1500 m(2)/g), without externally applied activating agents. Using cheap readily available agricultural residues such as oilseed rape straw, pyrolytic carbons can be produced with specific surface areas of around 950 m(2)/g.

전기영동적층법을 통한 판상 알루미나 입자와 전기영동 수지의 배향 유무기 복합체 제조 및 물성평가

Plate-shaped inorganic particles are coated onto a stainless steel substrate by the electrophoretic deposition of a precursor slurry which includes the inorganic particles of Al₂O₃ and polymer resin in mixed solvents to mimic the abalone shell structure, which is a composite of plate-shaped inorganic particles and organic interlayer binding materials with a layered orientation. The process parameters of the electrophoretic deposition include the voltage, coating time, and conductivity of the substrate. In addition, the suspension parameters are the particle size, concentration, viscosity, conductivity, and stability. We prepared an organic-inorganic composite coating with a high inorganic solid content by arraying the plate-shaped Al₂O₃ particles and electrophoretic resin via an electrophoretic deposition method. We analyzed the effect of the slurry composition and the electrophoretic deposition process parameters on the physical, mechanical and thermal properties of the coating layer, i.e., the thickness, density, particle orientation, Young"s modulus and thermogravimetric analysis results.

Structure/transport property relationships within nanoclay-filled polyurethane materials using polycaprolactone-based masterbatches

Abstract The lamellar structure of montmorillonite (MMT) clays exhibits an interesting potential to improve the barrier properties of thermoplastic polyurethanes (TPU). However direct melt blending of an ester-based TPU and functional organoclays, despite showing good filler dispersion, did not allowed for improving neither barrier properties (i.e., sorption and diffusion to water vapor) not mechanical performances with respect to the unfilled TPU. Therefore, two alternative strategies involving poly(e-caprolactone) (PCL)/organoclay masterbatches were explored to investigate the possibility to prepare materials with improved mechanical and barrier properties. In the first strategy, a PCL/organoclay masterbatch with high inorganic content was obtained by melt-blending (coined “free PCL” masterbatch), whereas in the second strategy PCL-grafted organoclay nanohybrids, also with high inorganic content were synthesized by in situ intercalative grafting/ring-opening polymerization of e-caprolactone (CL). Purposely, ROP of CL was initiated from hydroxyl groups available onto the MMT surface actually organo-modified by alkylammonium cations bearing hydroxyl functions (coined “nanohybrid PCL” masterbatch). These highly-filled PCL masterbatches (with ca. 25 wt% in inorganics) were then added into the ester-based TPU to prepare nanoclay/polyurethane nanocomposites by melt-blending. The morphology and dispersion of the resulting materials were characterized by X-ray diffraction and transmission electron microscopy. Improved sorption and diffusion properties towards water vapor as well as mechanical properties were measured. Herein, these results are discussed as a function of both clay dispersion and matrix/organoclay interaction.

Multifunctional Nanoclay Hybrids of High Toughness, Thermal, and Barrier Performances

To address brittleness of nanoclay hybrids of high inorganic content, ductile polymers (polyethylene oxide and hydroxyethyl cellulose) and montmorillonite (MTM) have been assembled into hybrid films using a water-based filtration process. Nacre-mimetic layered films resulted and were characterized by FE-SEM and XRD. Mechanical properties at ambient condition were studied by tensile test, while performance at elevated temperature and moisture conditions were evaluated by TGA, dynamic vapor sorption, and dynamic thermomechanical and hygromechanical analyses. Antiflammability and barrier properties against oxygen and water vapor were also investigated. Despite their high MTM content in the 60-85 wt % range, the hybrids exhibit remarkable ductility and a storage modulus above 2 GPa even in severe conditions (300°C or 94% RH). Moreover, they present fire-shielding property and are amongst the best oxygen and water vapor barrier hybrids reported in the literature. This study thus demonstrates nanostructure property advantages for synergistic effects in hybrids combining inexpensive, available, and environmentally benign constituents.

Preparation of Novel Corona-Resistance Polyimide/Spherical SiO&lt;sub&gt;2&lt;/sub&gt; Hybrid Films

In this study, a novel type of corona-resistance polyimide/spherical SiO2 hybrid films based on 3,3,4,4-biphenyltetracarboxylic dianhydride (s-BPDA) and 1,3-bis (4-aminophenoxy) benzene (1,3,4-APB) was synthesized by incorporation with different loadings of spherical SiO2 particles via in-situ polymerization. All the films were prepared by a so called two-step procedure and finally cured at 300°C. TEM images showed the SiO2 particles were homogeneously dispersed in the polyimide matrix by means of ultrasonic method and the addition of coupling agent. Experimental results indicated that the hybrid films with much higher inorganic content exhibited good thermal and mechanical properties as well as low water absorption. Especially, the dielectric strength and electric aging time of the hybrid films were obviously enhanced, which was attributed to the highly dispersed spherical SiO2. The morphology changes of the film surface caused by the electric field were also studied by scanning electron microscope (SEM).

Characterization and pollution potential assessment of Tunceli, Turkey municipal solid waste open dumping site leachates

Environmental monitoring of leachate quality from an open municipal solid waste dumping site in Tunceli, Turkey was studied in this research. The most commonly examined pollution parameters were determined on a seasonal basis. The annual average 5-day biological oxygen demand (BOD₅) and chemical oxygen demand (COD) values of station points were measured as 70 and 425 mg/L, respectively, and also the average BOD₅/COD ratio (a measure of biodegradability) was calculated as 0.20. The low ratio of biodegradability and slightly alkaline pH values in the leachate samples indicated that the site was characterized by methanogenic conditions. The mean ammonium-nitrogen (NH4 (+)-N) and corresponding phosphate (orthophosphate) values were assayed as 70 and 11 mg/L, respectively. The average solids content in the leachates was measured as 4,681 mg/L (total solids) and 144 mg/L (suspended solids). Very low concentrations of iron, manganese, copper, and zinc in the leachate samples were found and the concentration of cadmium was measured below detection limits. Excessive amount of nutrients and high organic and inorganic pollutant content in the leachates pose serious pollution potential to the environment. Since no drainage system or bio treatment exists in this open dumping site, high permeability of natural soil at the site and in the surrounding area and very fractured and crackled rocks under natural soil are indicators of high groundwater pollution potential in this site.

Targeting of the Osteoclastogenic RANKL–RANK Axis Prevents Osteoporotic Bone Loss and Soft Tissue Calcification in Coxsackievirus B3–Infected Mice

Bone mineralization is a normal physiological process, whereas ectopic calcification of soft tissues is a pathological process that leads to irreversible tissue damage. We have established a coxsackievirus B3 (CVB3)-infected mouse model that manifests both osteoporosis and ectopic calcification specifically in heart, pancreas, and lung. The CVB3-infected mice showed increased serum concentrations of both cytokines including IL-1β, TNF-α, and the receptor activator of NF-κB ligand (RANKL) that stimulate osteoclast formation and of the osteoclast-derived protein tartrate-resistant acid phosphatase 5b. They exhibited more osteoclasts in bone, with no change in the number of osteoblasts, and a decrease in bone formation and the serum concentration of osteoblast-produced osteocalcin. These results indicate that CVB3-induced osteoporosis is likely due to upregulation of osteoclast formation and function, in addition to decreased osteoblast activity. In addition, the serum in the CVB3-infected mice contained a high inorganic phosphate content, which causes ectopic calcification. RANKL treatment induced an increase in the in vitro cardiac fibroblast calcification by inorganic phosphate via the upregulation of osteogenic BMP2, SPARC, Runx2, Fra-1, and NF-κB signaling. We finally observed that i.p. administration of RANK-Fc, a recombinant antagonist of RANKL, prevented bone loss as well as ectopic calcification in CVB3-infected mice. Thus, our results indicate that RANKL may contribute to both abnormal calcium deposition in soft tissues and calcium depletion in bone. In addition, our animal model should provide a tool for the development of new therapeutic agents for calcium disturbance in soft and hard tissues.

Hybrid polymer sol–gel material for UV-nanoimprint: microstructure and thermal densification

Hybrid polymer solutions suitable for UV-nanoimprint were synthesized by combination of an alkoxysilane binder mixture with silica nanoparticles. Hydrolysis and condensation reactions were monitored by NMR and viscosity measurements. Thereby long-term stable systems were produced as a prerequisite for industrial application. Dip-coating of glass substrates and subsequent UV-curing yielded thin films. Their thermal densification and microstructural evolution resulted in pure glassy porous coatings, which were in detail characterized by N2-sorption measurements and ellipsometric porosimetry. Results emphasize the importance of the binder-particle interaction within these materials that are destined for the fabrication of microstructured surfaces by cost efficient and industrially feasible UV-based soft lithography. Structured glassy layers with high inorganic content show thermal stability up to >500 °C and have a high structure accuracy >85 %.

Carbon Sequestration and Release from Antarctic Lakes: Lake Vida and West Lake Bonney (McMurdo Dry Valleys)

Perennial ice covers on many Antarctic lakes have resulted in high lake inorganic carbon contents. The objective of this paper was to evaluate and compare the brine and CO2 chemistries of Lake Vida (Victoria Valley) and West Lake Bonney (Taylor Valley), two lakes of the McMurdo Dry Valleys (East Antarctica), and their potential consequences during global warming. An existing geochemical model (FREZCHEM-15) was used to convert measured molarity into molality needed for the FREZCHEM model, and this model added a new algorithm that converts measured DIC into carbonate alkalinity needed for the FREZCHEM model. While quite extensive geochemical information exists for ice-covered Taylor Valley lakes, such as West Lake Bonney, only limited information exists for the recently sampled brine of >25 m ice-thick Lake Vida. Lake Vida brine had a model-calculated pCO2 = 0.60 bars at the field pH (6.20); West Lake Bonney had a model-calculated pCO2 = 5.23 bars at the field pH (5.46). Despite the high degree of atmospheric CO2 supersaturation in West Lake Bonney, it remains significantly undersaturated with the gas hydrate, CO2·6H2O, unless these gas hydrates are deep in the sediment layer or are metastable having formed under colder temperatures or greater pressures. Because of lower temperatures, Lake Vida could start forming CO2·6H2O at lower pCO2 values than West Lake Bonney; but both lakes are significantly undersaturated with the gas hydrate, CO2·6H2O. For both lakes, simulation of global warming from current subzero temperatures (−13.4 °C in Lake Vida and −4.7 °C in West Lake Bonney) to 10 °C has shown that a major loss of solution-phase carbon as CO2 gases and carbonate minerals occurred when the temperatures rose above 0 °C and perennial ice covers would disappear. How important these Antarctic CO2 sources will be for future global warming remains to be seen. But a recent paper has shown that methane increased in atmospheric concentration due to deglaciation about 10,000 years ago. So, CO2 release from ice lakes might contribute to atmospheric gases in the future.