CO2 Inclusion Research Articles

Coordination Unsaturation and Basic Site-Immobilized Nanochannel in a Chemorobust MOF for 3-Fold-Increased High-Temperature Selectivity and Fixation of CO2 under Mild Conditions with Nanomolar Recognition of Roxarsone.

A multifaceted metal-organic framework (MOF) with task-specific site-engineered pores can promise high-temperature and moisture-tolerant capture and non-redox fixation of CO2 under mild conditions as well as ultrasensitive detection of carcinogenic contaminants in water. Herein, we report a pillar-bilayered MOF that holds a nanochannel with contrasting functionalities for both these sustainable applications with improved performance characteristics. The twofold entangled robust framework exhibits CO2 adsorption at elevated temperatures with considerable MOF-gas interaction. Interestingly, CO2 selectivity unveils nearly a 3-fold improvement upon the rise of temperature, affording a CO2/N2 value of 820 at 313 K, which outperforms many porous adsorbents. Additionally, breakthrough simulation establishes complete separation and attests the potential of this MOF in the separation of flue gas mixture. Importantly, minor CO2 loss during multiple capture-release cycles and under a relative humidity of 75% promise practical usability of the material. Density functional theory (DFT) not only portrays the atomistic level snapshots of temperature-triggered CO2 inclusion inside this microporous vessel alongside the role of diverse CO2-philic sites but also validates the basis of N2-phobicity of an azo-functionalized linker on such increased selectivity. The guest-free MOF further demonstrates non-redox and recyclable CO2 fixation with wide epoxide tolerance under solvent-free mild conditions and even works at atmospheric pressure and room temperature. The crucial roles of high-density acid-base sites in both adsorption and catalysis are supported by control experiments and by comparing the activity of an unfunctionalized MOF. The hydrolytic stability and strong luminescence signature benefit the framework in aqueous-phase selective and fast responsive detection of detrimental roxarsone (ROX) with high quenching (7.56 × 104 M-1) and very low sensitivity (68 nM). Apart from varying degrees of an energy-transfer mechanism, the fluorosensing of ROX is comprehensively supported by in-depth DFT studies that manifest alteration of MOF energy levels in the presence of organoarsenic compounds and depict MOF-analyte supramolecular interactions.

High-precision analysis of carbon isotopic composition for individual CO2 inclusions via Raman spectroscopy to reveal the multiple-stages evolution of CO2- bearing fluids and melts

The carbon isotopic composition of CO2 inclusions trapped in minerals reflects the origin and evolution of CO2-bearing fluids and melts, and records the multiple-stages carbon geodynamic cycle, as CO2 took part in various geological processes widely. However, the practical method for determination isotope composition of individual CO2 inclusion is still lacking. Developing a microanalytical technique with spatial resolution in micrometers to precisely determinate the δ13C value of individual CO2 inclusion, will make it possible to analyze a tiny portion of a zoning mineral crystal, distinguish the differences in micro-scale, and possible to find many useful information that could not be obtained with the bulk extraction and analysis techniques. In this study, we systematically collected Raman spectra of CO2 standards with different δ13C values (−34.9 ‰ to 3.58 ‰) at 32.0 °C and from ∼7.0 MPa to 120.0 MPa, and developed a new procedure to precisely determinate the δ13C value of individual CO2 inclusion. We investigated the relationship among the Raman peak intensity ratio, δ13C value, and CO2 density, and established a calibration model with high accuracy (0.5 ‰−1.5 ‰), sufficient for geological application to distinguish different source of CO2 with varying δ13CO2. As a demonstration, we measured the δ13C values and the density of CO2 inclusions in the growth zones of alkali basalt-hosted corundum megacrysts from Changle, Shandong Province. We found the significant differences of density and δ13C between the CO2 inclusions in the core of corundum and those inclusions in the outer growth zones, the δ13C value decreases from core to rim with decreasing density: δ13C values are from −7.5 ‰ to −9.2 ‰ for the inclusions in the core, indicating the corundum core was crystallized from mantle-derived magmas; from −13.5 ‰ to −18.5 ‰ for CO2 inclusions in zone 1 and from −16.5 ‰ to –22.0 ‰ for inclusions in zone 2, indicating the outer zones of corundum grew in a low δ13C value environment, resulted from an infilling of low δ13C value fluid and/or degassing of the ascending basaltic magma.

Fluid Inclusion and Titanite U-Pb Age Constraints on the Yuanjiang Ruby Mineralization in the Ailao Shan-Red River Metamorphic Belt, Southwest China

ABSTRACT The Yuanjiang marble-hosted ruby deposit lies in the central segment of the Ailao Shan metamorphic massif of the Ailao Shan-Red River metamorphic belt. The mineralizing fluid and age were characterized by detailed petrography, Raman spectroscopy, microthermometry, and in situ titanite laser ablation-inductively coupled plasma-mass spectrometry dating. Some fluid inclusions in the corundum show an interesting morphology with a diaspore crystal fully separating the whole inclusion into two smaller inclusions. This morphological feature can be explained by morphological ripening and subsequent reactions between the trapped H2O and the host corundum during the cooling of the inclusion. Fluid inclusions in the ruby belong to the system CO2–H2S–COS–S8–H2S2–CH4–AlO(OH) with various daughter minerals, including diaspore, gibbsite, and native sulfur (S8). The observed seven-component fluid inclusion composition can be explained by two steps: (1) original fluid inclusion capture during deposit formation with compositions including CO2, H2S, COS, CH4, S8, and H2S2, and (2) post-entrapment fluid inclusion modification, such as diaspore and gibbsite. The presence of hydrous minerals in fluid inclusions strongly supports the idea that water was once present in the initial fluids. In the Yuanjiang deposit, petrographic evidence shows that titanite formed simultaneously with ruby, and U-Pb dating of titanite allows us to conclude that the ruby mineralization formed at 23.4 ± 0.3 Ma, in other words during the Himalayan orogeny.

Effects of pressure and temperature conditions on thermodynamic and kinetic guest exchange behaviors of CH4 − CO2 + N2 replacement for energy recovery and greenhouse gas storage

Both natural gas production and CO2 sequestration can be simultaneously achieved in natural gas hydrates (NGHs) by using a guest swapping technique. In this study, the effects of replacement pressure (10.0–18.5 MPa) and temperature (274.2–277.2 K) conditions on the guest exchange behaviors of CH4 − CO2 + N2 replacement were investigated, focusing on the extent of replacement and replacement kinetics. At 274.2 K, the extent of replacement increased with injection pressure of CO2 (20%) + N2 (80%) gas, which is mainly attributed to a larger N2 inclusion at a higher pressure. At a higher temperature, the extent of replacement did not change, but CO2/N2 ratio in the replaced hydrates decreased slightly. An increase in the pressure led to an accelerated CO2 inclusion rate in the large (51262) cages at the initial stage and an enhanced N2 inclusion in the small (512) cages at the final stage. The enhanced replacement kinetics at a higher temperature is attributable to the increased inclusion rates of both CO2 and N2 at the initial stage of replacement. The results provide valuable insights into the guest swapping mechanism of CH4 − CO2 + N2 replacement occurring in NGH reservoirs with various locations and environments.

Effects of Pressure and Temperature Conditions on Thermodynamic and Kinetic Guest Exchange Behaviors of CH <sub>4</sub> − CO <sub>2</sub> + N <sub>2</sub> Replacement for Energy Recovery and Greenhouse Gas Storage

Both natural gas production and CO2 sequestration can be simultaneously achieved in natural gas hydrates (NGHs) by using a guest swapping technique. In this study, the effects of replacement pressure (10.0 – 18.5 MPa) and temperature (274.2 – 277.2 K) conditions on the guest exchange behaviors of CH4 − CO2 + N2 replacement were investigated, focusing on extent of replacement and replacement kinetics. At 274.2 K, the extent of replacement increased with injection pressure of CO2 (20%) + N2 (80%) gas, which is mainly attributed to a larger N2 inclusion at a higher pressure. At a higher temperature, the extent of replacement did not change, but CO2/N2 ratio in the replaced hydrates decreased slightly. An increase in the pressure led to an accelerated CO2 inclusion rate in the large cages at the initial stage and an enhanced N2 inclusion in the small cages at the final stage. The enhanced replacement kinetics at a higher temperature is attributable to the increased inclusion rates of both CO2 and N2 at the initial stage of replacement. The results provide valuable insights into the guest swapping mechanism of CH4 − CO2 + N2 replacement occurring in NGH reservoirs with various locations and environments.

Mechanism and kinetics of guest exchange in sII hydrate – Flue gas replacement as revealed by experimental and computational approaches for hydrocarbon recovery and CO2 sequestration

In this study, the kinetics of guest exchange in sII (CH4 (90%) + C3H8 (10%)) hydrate – flue gas (CO2 (20%) + N2 (80%)) replacement was investigated to elucidate the replacement mechanism and guest exchange characteristics for hydrocarbon recovery and CO2 sequestration. The Rietveld refinement of Powder X-ray diffraction (PXRD) patterns of the replaced hydrates at two pressures (11.0 MPa and 17.0 MPa) demonstrated that sII hydrate – flue gas replacement occurred iso-structurally. The time-dependent guest compositions in the hydrate phase and the cage occupancy of guest molecules were examined to understand the effect of pressure on guest exchange behaviors. The increased CO2 inclusion in both the small (512) and large (51264) cages at a higher pressure resulted in the larger production of CH4 and C3H8 and a lower N2/CO2 ratio in the hydrate phase. The slower inclusion rate and lower N2 occupancy in the small (512) cages at a higher pressure during replacement were observed due to the competitive inclusion of CO2 and N2 in the small (512) cages. The molecular dynamics (MD) simulation demonstrated that the expansion or shrinkage of hydrate cages caused by guest exchange has a significant impact on the lattice parameter of the replaced hydrates and it was influenced by not only the average molecular size of guest molecules in each cage but also the dispersive movement of the guest molecules in each cage.

An Aminopyridinium Ionic Liquid: A Simple and Effective Bifunctional Organocatalyst for Carbonate Synthesis from Carbon Dioxide and Epoxides.

An aminopyridinium ionic liquid is presented as a green, tunable, and active metal-free one-component catalytic system for the atom-efficient transformation of oxiranes and CO2 to cyclic carbonates. Inclusion of a positively charged moiety into aminopyridines, through a simple single-step synthesis, provides a one-component ionic liquid catalytic system with superior activity; effective in ring opening of epoxide, CO2 inclusion, and stabilization of oxoanionic intermediates. An efficiency assessment of a variety of positively charged aminopyridines was pursued, and the impact of temperature, catalyst loading, and the kind of nucleophile on the catalytic performance was also investigated. Under solvent-free conditions, this bifunctional organocatalytic system was used for the preparation of 18 examples of cyclic carbonates from a broad range of alkyl- and aryl-substituted oxiranes and CO2 , where up to 98 % yield and high selectivity were achieved. DFT calculations validated a mechanism in which nucleophilic ring-opening and CO2 inclusion occur simultaneously towards cyclic carbonate formation.

Time-dependent observation of a cage-specific guest exchange in sI hydrates for CH4 recovery and CO2 sequestration

CH4–CO2 replacement in naturally occurring gas hydrates has been considered a promising method for both energy recovery and CO2 sequestration. In this study, the time-dependent guest exchange behaviors and guest distributions during CH4–CO2 replacement were closely examined at two different CO2 injecting pressures (2.2 and 3.5 MPa) using nuclear magnetic resonance (NMR), in-situ Raman spectroscopy, powder X-ray diffraction (PXRD), and gas chromatography. The 13C NMR spectra confirmed that the cage occupancy ratio of the CH4 molecules in the large 51262 and small 512 cages (θL/θS,CH4) after the replacement was significantly smaller than that before the replacement because of the preferential occupation of CO2 in the large 51262 cages. The time-dependent Raman spectra revealed that the rate of CO2 inclusion and the resultant CH4 depletion in the hydrate phase during the replacement was faster at a higher CO2 injecting pressure. The Rietveld refinement of the PXRD patterns offered a quantitative cage occupancy of CH4 and CO2 molecules before and after the replacement. The time-dependent cage occupancy values of CH4 and CO2 during the replacement obtained from a multi-methodological approach, which is a combination of PXRD analysis and in-situ Raman measurement, demonstrated that a significant guest exchange in the large 51262 cages had a greater effect on the extent of replacement and that the kinetics of the CH4–CO2 replacement was accelerated at a higher CO2 injecting pressure. The results provide a better understanding of the kinetics and mechanism of the cage-specific CH4–CO2 replacement occurring in the sI hydrates for CH4 recovery and CO2 sequestration.

CO2 inclusion complexes of Granular V-type crystalline starch: Structure and release kinetics

Granular V-type crystalline starch (V-type starch) was prepared using different starch varieties by alcoholic-alkaline treatment. Carbon dioxide was encapsulated into V-type starch using a solid encapsulation method. The morphological and structural properties of the inclusion complexes (ICs) were characterised using scanning electron microscopy and X-ray diffraction. Fourier-transform infrared spectroscopy and 13C Nuclear Magnetic Resonance proved that CO2 was successfully encapsulated. The encapsulation capacity of V-type starches was determined by head space gas chromatography, and ICs made from normal maize starch achieved the highest CO2 concentration (2.55%, w/w). The controlled release characteristics of ICs were also determined at various temperatures and relative humidity, and ICs made from normal potato starch exhibited slower release characteristics. The release kinetics showed that the release of CO2 from ICs was accelerated by increasing temperature or RH. V-type starch is a renewable, inexpensive material for encapsulation of gasses such as CO2.

Guest gas enclathration in tetra-n-butyl ammonium chloride (TBAC) semiclathrates: Potential application to natural gas storage and CO2 capture

The enclathration of guest gases such as CH4 and CO2 in tetra-n-butyl ammonium chloride (TBAC) semiclathrates and their potential application to natural gas storage and CO2 capture were examined with a primary focus on stability condition measurements and cage filling characteristics. The phase behaviors clearly demonstrated that the double CH4 (or CO2)+TBAC semiclathrates yielded a significantly enhanced thermodynamic stability. In particular, the highest stabilization occurred at 3.3mol%, the stoichiometric concentration of TBAC·29.7H2O. The cage-dependent 13C NMR chemical shift identified CH4 molecules enclathrated in the small 512 cages of the double TBAC semiclathrates. CO2 inclusion in the double TBAC semiclathrate was also confirmed using Raman spectroscopy. In addition, the dissociation enthalpy and the dissociation temperature of the TBAC semiclathrate under atmospheric pressure were measured to be 204.8±1.7J/g and 288.0K, respectively, by a differential scanning calorimeter. The experimental results demonstrate that TBAC semiclathrates can potentially be used for gas storage and CO2 capture due to their high thermodynamic stability and favorable enclathration characteristics of guest gases.

Fluid evolution of the Paleoproterozoic Hujiayu copper deposit in the Zhongtiaoshan region: Evidence from fluid inclusions and carbon–oxygen isotopes

The Zhongtiaoshan region, located in the southern margin of the North China Craton, is the host to a number of metamorphosed sediment-hosted stratiform copper deposits. These deposits are hosted by dolomitic marble and silicic albitite of the mid-Paleoproterozoic Zhongtiao Group and contain economically significant copper and cobalt. The formation of these deposits is considered to be closely associated with the evolution of the Paleoproterozoic “Zhongtiao” rift. The Hujiayu deposit, the second largest Cu deposit of this type, is mainly hosted in silicic albitite and dolomitic marble in the upper part of the Bizigou Formation but locally extends into carbonaceous shales at the bottom of the Yujiashan Formation. Mineralization of the Hujiayu Cu deposit can be divided into an early stage (diagenetic stage) with disseminated to veinlet sulfides and a late stage (metamorphism stage) with coarse-vein sulfides. Mineral assemblages are similar for the two stages, with major minerals as chalcopyrite, pyrite, and pyrrhotite and main gangue minerals as dolomite and quartz. Sulfide veinlets formed in the early stage are thin and discrete, and have irregular boundaries with the host rocks; whereas the ore-bearing veins of the late stage are controlled by fractures.Five types of fluid inclusions are recognized in the Hujiayu Cu deposit and they are: (1) pure vapor and vapor-rich inclusion (V-type), (2) pure CO2 inclusion (PC-type), (3) CO2–H2O inclusion (C-type), (4) liquid-rich inclusion (L-type), and (5) daughter mineral-bearing inclusion (S-type). Microthermometric analysis shows that the ore-forming fluids of the early mineralization stage are characterized by high salinity (22–40wt.% NaCl equiv.) and moderate temperature (120–280°C). The ore-forming fluids of the late mineralization stage are characterized by CO2 enrichment, high salinity, high temperature and underwent significant unmixing at a temperature interval of 240–480°C. Compositions of the ore-forming fluids in the early and late stages are interpreted to be mainly basinal brine and metamorphic hydrothermal solution, respectively. Carbon and oxygen isotope compositions suggest possible carbon isotope exchange between the ore-forming fluids and organic-rich carbonaceous shales during the early stage. In the late mineralization stage, both degassing of CO2 and isotopic exchange with organic carbon may have contributed to the formation of the more negative δ13CV-PDB values of mineralized carbonates.The early stage mineralization of the Hujiayu Cu deposit may have occurred via interaction of oxidized Cu-bearing brines from the red-bed in the lower segment of the Bizigou Formation with the overlying reductive carbonaceous shales. Late stage mineralization at Hujiayu was mainly triggered by CO2 escaping from metamorphic hydrothermal solutions.

Fluid Inclusions and Metallization of the Kendekeke Polymetallic Deposit in Qinghai Province, China

Abstract:The Kendekeke polymetallic deposit, located in the middle part of the magmatic arc belt of Qimantag on the southwestern margin of the Qaidam Basin, is a polygenetic compound deposit in the Qimantag metallogenic belt of Qinghai Province. Multi‐periodic ore‐forming processes occurred in this deposit, including early‐stage iron mineralization and lead‐zinc‐gold‐polymetallic mineralization which was controlled by later hydrothermal process. The characteristics of the ore‐forming fluids and mineralization were discussed by using the fluid inclusion petrography, Laser Raman Spectrum and micro‐thermometry methods. Three stages, namely, S1‐stage (copper‐iron‐sulfide stage), S2‐stage (lead‐zinc‐sulfide stage) and C‐stage (carbonate stage) were included in the hydrothermal process as indicated by the results of this study. The fluid inclusions are in three types: aqueous inclusion (type I), CO2‐aqueous inclusion (type II) and pure CO2 inclusion (type III). Type I inclusions were observed in the Si‐stage, having homogenization temperature at 240–320°C, and salinities ranging from 19.8% to 25.0% (wt% NaCl equiv.). All three types of inclusions, existing as immiscible inclusion assemblages, were presented in the S2‐stage, with the lowest homogenization temperature ranging from 175 °C to 295°C, which represents the metallogenic temperature of the S2‐stage. The salinities of these inclusions are in the range of 1.5% to 16%. The fluid inclusions in the C‐stage belong to types I, II and III, having homogenization temperatures at 120–210°C, and salinities ranging from 0.9% to 14.5%. These observations indicate that the ore‐forming fluids evolved from high‐temperature to low‐temperature, from high‐salinity to low‐salinity, from homogenization to immiscible separation. Results of Laser Raman Spectroscopy show that high density of CO2 and CH4 were found as gas compositions in the inclusions. CO2, worked as the pH buffer of ore‐forming fluids, together with reduction of organic gases (i.e. CH4, etc), affected the transport and sediment of the minerals. The fluid system alternated between open and close systems, namely, between lithostatic pressure and hydrostatic pressure systems. The calculated metallogenic pressures are in the range of 30 to 87 Mpa corresponding to 3 km mineralization depth. Under the influence of tectonic movements, immiscible separation occurred in the original ore‐forming fluids, which were derived from the previous high‐salinity, high‐temperature magmatic fluids. The separation of CO2 changed the physicochemical properties and composition of the original fluids, and then diluted by mixing with extraneous fluids such as meteoric water and groundwater, and metallogenic materials in the fluids such as lead, zinc and gold were precipitated.

Fermi resonance in solid CO2 under pressure

The symmetric-stretching fundamental (ν1) and the bending first overtone (2ν2) of CO2, which are accidentally degenerate with the same symmetry, undergo a Fermi resonance and give rise to two Raman bands with a frequency difference of 107 cm(-1) and an intensity ratio of 2.1. Both the frequency difference and intensity ratio can be varied by pressure applied to CO2 in condensed phases, which has been utilized as a spectroscopic geobarometer for minerals with CO2 inclusion. This study calculates the pressure dependence of the Fermi dyad frequency difference and intensity ratio by combining the embedded-fragment second-order Mo̸ller-Plesset perturbation calculations of harmonic frequencies of solid CO2 under pressure and the coupled-cluster singles and doubles with noniterative triples and vibrational configuration-interaction calculations of anharmonic frequencies of molecular CO2. It reproduces frequency difference quantitatively and intensity ratio qualitatively up to 10 GPa. The analysis of the results is shown to render strong support for one particular order of unperturbed frequencies, ν1 > 2ν2, in both the gas and solid phases, which has been a matter of controversy for decades.

Conformity and precision of CO2 densimetry in CO2 inclusions: microthermometry versus Raman microspectroscopic densimetry

To assess the ability of densimetry for CO2 fluid in CO2 inclusions, we compare two methods, microthermometry and Raman microspectroscopic densimetry for CO2. The comparative experiment was performed for nine CO2 inclusions in three mantle xenoliths. The results are as follows: (1) microthermometry precisely determines CO2 density with the range of 0.65 to 1.18 g/cm3 compared with Raman microspectroscopic densimetry; (2) CO2 density obtained by Raman microspectroscopic densimetry is fairly consistent with that by microthermometry; (3) it is hard to determine CO2 density in CO2 inclusion with diameter of less than around 3 µm using microthermometry; and (4) microthermometry can be applied only to the CO2 inclusion whose CO2 density ranges from around 0.65 to 1.18 g/cm3, whereas the Raman microspectroscopic densimetry is applicable to CO2 density ranging from 0.1 to 1.24 g/cm3. The above features carry the potential for estimation of depth origin of mantle‐derived rocks. The depth where the rocks were trapped by host magma can be estimated using both geothermometric data and CO2 fluid density in CO2 inclusions in the rocks. Typical precisions of density of CO2 in CO2 inclusions obtained by the Raman microspectroscopic densimetry (~0.01 g/cm3) and by the microthermometry (< 0.001 g/cm3) correspond to uncertainties in the depth origin of 2.4 km and < 1.7 km, respectively, at 1000 ± 50 °C. In case of the mantle under 750–1250 °C and 1 GPa, the CO2 fluid has a density ranging from 1.06 g/cm3 to 1.21 g/cm3, which are well measured by the Raman microspectroscopic densimetry. Combination of both densimetries for CO2 in mantle minerals elucidates the deep structure of the Earth. Copyright © 2012 John Wiley & Sons, Ltd.

Computational Studies of Load-Dependent Guest Dynamics and Free Energies of Inclusion for CO2 in Low-Density p-tert-Butylcalix[4]arene at Loadings up to 2:1

The structure, dynamics, and free energies of absorption of CO(2) by a low-density structure (P4/n) of calixarene p-tert-butylalix[4]arene (TBC4) at loadings up to 2:1 CO(2):TBC4 have been studied by using molecular dynamics simulations with two sources of initial TBC4 structures (TBC4-T and TBC4-U). The CO(2)/TBC4 complex structure is very sensitive to the initial lattice spacing of TBC4. From the computed radial distribution functions of CO(2) molecules, a CO(2) dimer is observed for TBC4-T and a cage-interstitial CO(2) structure is suggested for TBC4-U. The dynamics of the CO(2) molecules show little initial TBC4 structural dependency. The free energy of inclusion for a single CO(2) in this TBC4 structure for various loadings is -4.0 kcal/mol at 300 K and -1.8 kcal/mol at 450 K, showing that CO(2) inclusion is favored. The fully loaded 1:1 CO(2):TBC4 system is slightly less favorable at -3.9 and -1.2 kcal/mol at 300 and 450 K, respectively. The first CO(2) added beyond 1:1 loading shows a significant drop in absorption energy to -1.9 and +1.9 kcal/mol at 300 and 450 K. These data are consistent with experimental results showing that low-density structures of TBC4 are able to absorb CO(2) at loadings greater than 1:1 but retention is lower than for 1:1 loaded systems indicating the free energy of inclusion for addition of the CO(2) above 1:1 is less favorable.

Physicochemical properties of antifungal drug–cyclodextrin complexes prepared by supercritical carbon dioxide and by conventional techniques

Antifungal drugs are the most common systemic drugs used for the treatment of oropharyngeal candidiasis, which is the first symptom of HIV infection. However, the efficacy and bioavailability of these drugs have been limited by their poor aqueous solubility and dissolution rate. Therefore, the aim of this study was to investigate the effect of different preparation methods (i.e. kneading, coevaporation, sealed-heating, and a solid inclusion technique using supercritical carbon dioxide carrier (SC CO 2-inclusion)) for obtaining solid inclusion complexes between β-cyclodextrin and three antifungal drugs (itraconazole, econazole, and fluconazole). The physicochemical properties of the different products were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffractometry (PXRD). For the complexes prepared by the SC CO 2-inclusion method, the effects of temperature and pressure have also been investigated. Results suggested the possibility of complex formation between β-cyclodextrin and the three antifungal agents, and indicated that inclusion formation was influenced by the preparation technique. SC CO 2-inclusion method proved to be an effective technique for preparing solid-state inclusion complexes between β-cyclodextrin and antifungal drugs, avoiding the use of organic solvents. Moreover, temperature of the SC CO 2 played a major role in promoting drug–carrier interactions, whereas pressure had limited effects.

CO2 and H2 Gas Mixture Inclusion Effect on Shrinkage of Ar Induction Thermal Plasmas

In the present work, effect of CO2+H2 gas mixture inclusion on shrinkage of plasma was numerically investigated on high power Ar inductively coupled thermal plasmas at atmospheric pressure. The gas mixture of CO2+H2 has many reactions in wide temperature range of 300-20000K which may cause some performance in thermal plasmas. Simulation has been carried out solving a two-dimensional local thermodynamic equilibrium (LTE) code. The active plasma power and input fundamental frequency were fixed at 27kW and 450kHz respectively. The main variable parameter was the admixture ratio of secondary gas (CO2+H2 gas mixture) and it has been found that the injection of excess dissociative molecular gases shrink the plasma in radius keeping the center temperature about 10,000K by investigating the plasma radius having temperature beyond 5,000K for each of the case. The result also shows that increasing the inclusion (admixture ratio) of CO2+H2 molecular gas raises the plasma peak temperature. The result is also compared with that of Ar-CO2 and Ar-H2 thermal plasma and finally a comparative study and conclusions have been made.

Fluid inclusions evidence for differential exhumation of ultrahigh pressure metamorphic rocks in the Sulu terrane

Differential exhumation was petrologically recognized in ultrahigh pressure metamorphic rocks from the southern and northern parts of the Sulu terrane. While a normal exhumation occurred for eclogites and gneisses in south Sulu, granulite-facies overprinting of ultrahigh pressure metamorphic rocks took place with high retrograde temperatures in north Sulu. A study of fluid inclusions reveals trapping of five type fluid inclusions in high and ultrahigh pressure eclogite minerals and vein quartz in the Sulu terrane. These are A-type N2±CO2 inclusion trapped at high and ultra-high pressure eclogite-facies metamorphic condition, B-type pure-CO2 liquid phase inclusion with higher density trapped during granulite-facies overprinting metamorphism of eclogites, C-type CO2−H2O inclusion and D-type hypersaline inclusion trapped in high pressure eclogite-facies re-crystallization stage, and E-type low salinity H2O inclusion trapped in the latest stage of ultrahigh pressure exhumation (amphibolite-facies retrogression). Identification of crowded-distributing pure-CO2 liquid inclusions with higher density trapped in garnet of eclogites provides an evidence for granulite-facies overprinting metamorphism in the north Sulu terrane.

Estimation of X CO2 , P, and fluid inclusion volume from fluid inclusion temperature measurements in the system NaCl-CO 2 H 2 O

Estimation of X CO2 , P, and fluid inclusion volume from fluid inclusion temperature measurements in the system NaCl-CO 2 H 2 O