Showing papers in "Journal of Chemical & Engineering Data in 2015"

The Strengthening Role of the Amino Group in Metal–Organic Framework MIL-53 (Al) for Methylene Blue and Malachite Green Dye Adsorption

Abstract: In this paper, two kinds of metal–organic frameworks (MOFs), MIL-53(Al) and MIL-53(Al)-NH2, were synthesized. Then these MOFs were used to remove methylene blue and malachite green dyes from aqueous solution. Characterizations of MOFs were carried out by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectrometry, and zeta potential. Experimental results showed that MIL-53(Al)-NH2 can rapidly bind to the two kinds of cationic dyes from aqueous solution with high adsorption capacity. However, the adsorption capacity of MIL-53(Al) for cationic dyes is extremely low. The adsorptive selectivity of MIL-53(Al)-NH2 to the cationic dyes resulted from the hydrogen bonding interaction between amimo groups of the dyes molecule and the MIL-53(Al)-NH2, while the extremely low adsorption capacity of MIL-53(Al) for the dyes may be main caused by the “breathing” behavior of MIL-53(Al). The factors including adsorption time, temperature, and the pH of solution that a...

Methane Hydrates in Nature—Current Knowledge and Challenges

Abstract: Recognizing the importance of methane hydrate research and the need for a coordinated effort, the United States Congress enacted the Methane Hydrate Research and Development Act of 2000. At the same time, the Ministry of International Trade and Industry in Japan launched a research program to develop plans for a methane hydrate exploratory drilling project in the Nankai Trough. India, China, the Republic of Korea, and other nations also have established large methane hydrate research and development programs. Government-funded scientific research drilling expeditions and production test studies have provided a wealth of information on the occurrence of methane hydrates in nature. Numerous studies have shown that the amount of gas stored as methane hydrates in the world may exceed the volume of known organic carbon sources. However, methane hydrates represent both a scientific and technical challenge, and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate resea...

Thermochemistry of Halogen-Substituted Methylbenzenes

Abstract: Experimental vapor pressures, vaporization, fusion, and sublimation enthalpies of a number of bromo- and iodo-substituted methylbenzenes have been studied by transpiration method in order to evaluate a series of experimental measurements that appear to be internally self-consistent. The compounds studied in this regard include bromobenzene, iodobenzene, 1-bromo-2-methylbenzene, 1-bromo-3-methylbenzene, 1-bromo-4-methylbenzene, 1-iodo-2-methylbenzene, 1-iodo-3-methylbenzene, 1-iodo-4-methylbenzene, 1-bromo-2,6-dimethylbenzene, 1-iodo-2,6-dimethylbenzene, and 1-iodo-2,4-dimethylbenzene. Gas-phase enthalpies of formation of halogen-substituted methylbenzenes were calculated by using quantum-chemical methods. Simple group-additivity procedures were developed for estimation of vaporization enthalpies and gas-phase and liquid-phase enthalpies of formation of halogen-substituted methylbenzenes.

Adsorptive Removal of Pb(II) Ions from Aqueous Samples with Amino-Functionalization of Metal–Organic Frameworks MIL-101(Cr)

Abstract: Metal organic frameworks (MOFs) have been regarded as robust adsorbents for the adsorptive removal of organic pollutants because of their unique characteristics. However, the application of MOFs in the removal of metals from water is still rare. In this paper, amino-functionalization of Cr-based MOFs MIL-101 are modified through coordination bonding of unsaturated Cr metal centers with the -NH2 group in ethylenediamine (ED), and we demonstrate their excellent performance for the removal of Pb(II) ions from water. The Fourier transform infrared verifies that the ethylenediamine was grafted successfully on MIL-101. Furthermore, the results of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy show that the structure of ED-MIL-101 with an appropriate amount of ED almost does not collapse and retains the original performance of MIL-101. The adsorption capacity of ED-MIL-101, which is more than five times that of MIL-101, is 81.09 mg.g(-1) for Pb(II) ions from aqueous samples. The selectivity coefficients of ED-MIL-101 for Pb(II)/Cu(II), Pb(II)/Zn(II), Pb(II)/Co(II), and Pb(II)/Ni(II) are 6.92, 24.02, 15.69, and 14.53, respectively. The adsorption kinetics of Pb(II) ions shows that the process fits well with a pseudo-second-order model, and the adsorption equilibrium time is only about 30 min. Moreover, the practical application of ED-MIL-101 achieves almost 97.22% removal efficiency for Pb(II) ions. These results indicate that ED-MIL-101 has great potential in selectively removing Pb(II) ions from water environment.

Dependence of Refractive Index on Concentration and Temperature in Electrolyte Solution, Polar Solution, Nonpolar Solution, and Protein Solution

Abstract: The dependence of refractive index on the concentration and temperature in six kinds of aqueous solutions was investigated. The six solutions were three electrolyte solutions (NaCl, KCl, and CaCl2), a polar solution (glucose solution), a nonpolar solution (ethyl acetate solution), and a protein solution (bovine serum albumin solution). It was found that dn/dc decreased with temperature and dn/dT decreased with concentration in polar, nonpolar, and electrolyte solutions. While in protein solution, both of the derivatives showed an opposite behavior due to the thermal aggregation effect of proteins. According to the experimental results, the empirical expressions of the refractive indices in terms of both concentration and temperature were derived for the six solutions. By having the derivatives of refractive index n with respect to concentration c (dn/dc) and with respect to temperature T (dn/dT) respectively from the expressions, the dependence of (dn/dc) on temperature and that of (dn/dT) on concentratio...

Simultaneous Removal of Cationic and Anionic Dyes from Environmental Water Using Montmorillonite-Pillared Graphene Oxide

Abstract: We investigate the removal of methyl orange (MO) and methylene blue (MB) from aqueous solution by montmorillonite-pillared graphene oxide (MGO). Experimental conditions were used that evaluate the potential of MGO in removing anionic and cationic dyes in single and binary systems, and we investigated the uptake capacity of MGO toward organic dye as a function of different pH, adsorbent dosage, temperature, and adsorption time. In the single system, the Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and calculate the isotherm constants. Moreover, the pseudo-first-order and pseudo-second-order kinetic models were applied to study the mechanism of MGO adsorbing dyes. Thermodynamic studies demonstrated that the adsorption of MO and MB onto MGO was feasible and spontaneous. In the binary system, the adsorption capacities of MO and MB by MGO were dramatically higher than those in a single system. Therefore, through the recorded adsorption results under different conditi...

Densities, Viscosities, and Conductivities of the Imidazolium Ionic Liquids [Emim][Ac], [Emim][FAP], [Bmim][BETI], [Bmim][FSI], [Hmim][TFSI], and [Omim][TFSI]

Abstract: Data for the transport properties electrical conductivity, κ, and dynamic viscosity, η, of the imidazolium ionic liquids [Emim][FAP], [Emim][Ac], [Bmim][BETI], [Bmim][FSI], [Hmim][TFSI], and [Omim][TFSI] (κ only) is presented. Electrical conductivity has been studied in the wide temperature range of (273.15 to 468.15) K, whereas η was determined in the range of (273.15 to 408.15) K. The data could be well fitted by the empirical Vogel–Fulcher–Tammann equation. Additionally, the densities of these ionic liquids, showing a linear dependence on temperature, were collected from (273.15 to 363.15) K.

Density, Surface Tension, and Kinematic Viscosity of Hydrofluoroethers HFE-7000, HFE-7100, HFE-7200, HFE-7300, and HFE-7500

Abstract: The liquid density, liquid kinematic viscosity, and surface tension of the segregated hydrofluoroethers (HFEs) HFE-7000 (1,1,1,2,2,3,3-heptafluoro-3-methoxy-propane), HFE-7100 (mixture of the isomers 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxy-butane and 1,1,1,2,3,3-hexafluoro-3-methoxy-2-(trifluoromethyl)propane), HFE-7200 (mixture of the isomers 1-ethoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane and 1-ethoxy-1,1,2,3,3,3-hexafluoro-2-(trifluoromethyl)propane), HFE-7300 (1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane), and HFE-7500 (3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-(trifluoromethyl)hexane) were studied in dependence on temperature under saturation conditions. A vibrating-tube densimeter was used for the measurement of the saturated-liquid density at temperatures from (273.15 to 363.15) K with a relative expanded uncertainty (k = 2) of 0.02 %. The kinematic viscosity of the liquid phase and surface tension were obtained on the basis of surface light scattering (SLS) measurements for...

Effect of Temperature, Anion, and Alkyl Chain Length on the Density and Refractive Index of 1-Alkyl-3-methylimidazolium-Based Ionic Liquids

Abstract: The density and refractive index of 15 room temperature ionic liquids (ILs) grouped according to whether they had the same cation or anion have been measured at atmospheric pressure in a temperature range from 293.15 K to 343.15 K. Changes in the physical properties have been quantified as a function of temperature and alkyl chain length for each cation or anion family. It has been observed that ionic liquid density increases when the alkyl length of the cation decreases but not with the molecular weight of the anion. We have proposed a new method to assign the ionic volume of each component in an IL that explains the trend, followed by all experimental data in this work, and allows us to predict the molecular volume and density of many ILs prior to synthesis. It was also seen that the refractive index increases as alkyl chain length of the cation increases. The temperature-dependent correlation between density and refraction index for the ILs studied has been quantified.

Recent Advances in Silica-Based Materials for the Removal of Hexavalent Chromium: A Review

Abstract: Hexavalent chromium [Cr(VI)], one of the most toxic contaminants, is released in the environment due to various anthropogenic activities. Exposure of Cr(VI) can pose a serious threat to the public health as well as flora and fauna. Effective treatment of Cr(VI) is, therefore, very essential from safety, health, and environment points of view. The present review focuses on the development of silica-based materials for the adsorption of Cr(VI) from wastewater. After discussing toxicity issues and general removal methods of Cr(VI), the importance of silica materials are highlighted. The silica has different shapes, sizes, surface areas, and pore diameters and, hence, can play a vital role in designing the adsorbent. They can be modified into organic, inorganic, polymeric, biological, and ionic liquid based materials. Therefore, they are broadly classified into these five categories. The adsorption isotherms and kinetics of these materials for Cr(VI) are discussed and compared with each other. Future prospect...

Hydrate Management in Practice

Abstract: This paper describes the hydrate management strategies in Statoil’s gas and oil production systems. Hydrate management is a risk based approach allowing operations within the hydrate domain when the risk for hydrate plugging is concluded to be low. This is in sharp contrast to the hydrate avoidance approach practiced by Statoil in the past. Statoil has over 500 subsea wells and more than 100 subsea flowlines in operation. The hydrate management strategies take advantage of the intrinsic properties of the fluid systems, the hydrodynamics, and the plugging risk related to the amount of water present in the different parts of the production systems. This approach is based on a large body of research performed at Statoil and on extensive field experiences. Statoil’s current best practices in different production systems are described, and relevant examples from the field operations are provided.

Comparison of Optimized Isotherm Models and Error Functions for Carbon Dioxide Adsorption on Activated Carbon

Abstract: The adsorption of CO2 on commercial activated carbon WG12 and WG12 modified by ZnCl2 and KOH was investigated using a high pressure Sievert’s apparatus. The experimental data were analyzed using Langmuir, Freundlich, Sips, Toth, Unilan, Ftitz–Schlunder, and Redlich–Peterson equations. An error analysis was performed to examine the effect of using different error criteria for the isotherm parameters determination. Five error analysis methods were used: the sum of the squares of errors, the hybrid fractional error function, the average relative error, the Marquardt’s percent standard deviation, and the sum of the absolute errors. The Sips isotherm provided the best quality of fitting for all the experimental data. Error function analysis found that sum of the squares of the errors and hybrid fractional error function provided the best overall results.

Thermodynamic Properties of trans-1-Chloro-3,3,3-trifluoropropene (R1233zd(E)): Vapor Pressure, (p, ρ, T) Behavior, and Speed of Sound Measurements, and Equation of State

Abstract: We present experimental measurements of the density, speed of sound, and vapor pressure of trans-1-chloro-3,3,3-trifluoropropene, which is also known as R1233zd(E). Densities were measured over the temperature range from (215 to 444) K, with pressures from (0.3 to 24.1) MPa. Sound speed data were measured at temperatures between (290 and 420) K, with pressures from (0.07 to 2.1) MPa. Vapor pressures span the temperature range from (280 to 438) K. The experimental data cover the saturation curve, the vapor and liquid phases, and also the vicinity of the critical point. Densities and vapor pressures were measured in a two-sinker densimeter with a magnetic suspension coupling. Sound speed data were measured with a spherical acoustic resonator. An equation of state written in terms of the Helmholtz energy was developed; it represents the present experimental data with relative root-mean-square deviations of 0.020 % for densities, 0.223 % for vapor pressures, and 0.131 % for speeds of sound.

Adsorption of Pure and Binary CO2, CH4, and N2 Gas Components on Activated Carbon Beads

Abstract: The adsorption equilibriums of CO2, CH4, and N2 pure gases on pitch-based activated carbon beads have been studied using a magnetic suspension microbalance at (293, 303, 333, and 363) K within a pressure range of 0 kPa to 4000 kPa. It is found that experimental adsorption capacities can be successfully described with both the Sips and Multisite Langmuir (MSL) isotherm models. Afterward, binary competitive adsorption breakthrough experiments (CO2/CH4 and CH4/N2) at 303 K and adsorption isotherms of gas mixtures under different conditions have been measured. Theoretical calculations from Sips model-based ideal adsorbed solution theory are found to have better agreement with experimental data of competitive binary adsorption than that from MSL model. Promising adsorption selectivity (5.5) between CH4 and N2 is obtained at 303 K as the pressure of a binary gas mixture is 100 kPa with yCH4 = 0.5 in the feed. Therefore, the activated carbon beads reported in this study can be considered as a promising adsorbent...

Permafrost-Associated Gas Hydrate: Is It Really Approximately 1 % of the Global System?

Abstract: Permafrost-associated gas hydrates are often assumed to contain ∼1 % of the global gas-in-place in gas hydrates based on a study26 published over three decades ago. As knowledge of permafrost-associated gas hydrates has grown, it has become clear that many permafrost-associated gas hydrates are inextricably linked to an associated conventional petroleum system, and that their formation history (trapping of migrated gas in situ during Pleistocene cooling) is consistent with having been sourced at least partially in nearby thermogenic gas deposits. Using modern data sets that constrain the distribution of continuous permafrost onshore5 and subsea permafrost on circum-Arctic Ocean continental shelves offshore and that estimate undiscovered conventional gas within arctic assessment units,16 the analysis done here reveals where permafrost-associated gas hydrates are most likely to occur, concluding that Arctic Alaska and the West Siberian Basin are the best prospects. A conservative estimate is that 20 Gt C (2...

Density, Speed of Sound, Viscosity, and Excess Properties of Binary Mixtures Formed by Ethanol and Bis(trifluorosulfonyl)imide-Based Ionic Liquids

Abstract: In this work, viscosities, densities, and speeds of sound of three binary mixtures containing the ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim][NTf2], 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][NTf2], and 1-hexyl-3-methylimidazo-lium bis(trifluoromethylsulfonyl)imide, [hmim][NTf2], mixed with ethanol were measured at atmospheric pressure in the range of (278.15 to 338.15) K, covering the entire range of compositions. From these experimental data, the excess isentropic compressibility and molar isentropic compressibility of pure components and mixtures have been calculated. Additionally, excess properties, such as viscosity deviation, excess molar volume, excess isentropic compressibility, and excess molar isentropic compressibility, have been calculated and fitted with the Redlich–Kister polynomial equation.

Experiments and Thermodynamic Modeling of the Solubility of Carbon Dioxide in Three Different Deep Eutectic Solvents (DESs)

Abstract: Carbon capture and storage is needed to reduce the anthropogenic emissions of carbon dioxide (CO2) in atmosphere. Deep eutectic solvents (DESs), due to their low vapor pressure and environmentally benign nature are possible solvents for the carbon capture step. In the present study, the solubility of CO2 in three DESs, namely, reline (choline chloride and urea in a 1:2 molar ratio), ethaline (choline chloride and ethylene glycol in a 1:2 molar ratio), and malinine (choline chloride, malic acid, and ethylene glycol in a 1.3:1:2.2 molar ratio) has been studied in a temperature range of (309 to 329) K at pressures up to 160 kPa. Henry’s constants for CO2–DES systems have been determined under these conditions with values in the range of (3.7 to 6.1) MPa (on a molality basis). Thermodynamic modeling using a modified Peng–Robinson equation of state was used to correlate the experimental data. Results showed excellent agreement with a maximum average absolute relative deviation of 1.6% calculated over the compl...

Bifunctionalized Metal Organic Frameworks, UiO-66-NO2-N (N = -NH2, -(OH)2, -(COOH)2), for Enhanced Adsorption and Selectivity of CO2 and N2

Abstract: Metal organic frameworks (MOFs), UiO-66-NO2 and UiO-66-NO2–N (N = -NH2, -(OH)2, -COOH)2), were synthesized under solvothemal conditions using different functionalized organic linkers. The synthesized samples were further activated by solvent exchange using methanol and chloroform. All samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and N2 adsorption/desorption. Gas adsorption of CO2 and N2 on all samples has been evaluated at 760 mmHg and different temperatures. It was found that UiO-66-NO2-NH2 by methanol or chloroform activation presented much higher CO2 adsorption than other samples and the adsorption capacities are around (87 and 74) cm3·g–1 on chloroform-activated and methanol-activated samples, respectively, at 273 K and 760 mmHg. In addition, high selectivity of CO2/N2 has been found on chloroform-activated UiO-66-NO2-NH2 giving a factor of 65 while the selectivity of CO2/N2 is onl...

Solubility and Diffusivity of CO2 in the Ionic Liquid 1-Butyl-3-methylimidazolium Tricyanomethanide within a Large Pressure Range (0.01 MPa to 10 MPa)

Abstract: Ionic liquids (ILs) are promising solvents for carbon capture because of their high sorption capacity and low regeneration energy compared to conventional amine-based solvents. Previously, tetracyanoborate-based ILs have shown enhanced carbon dioxide (CO2) absorption capacity and absorption kinetics due to their low viscosity.1 In this work, the related IL 1-butyl-3-methylimidazolium tricyanomethanide ([bmim][tcm]) is studied for the first time as a solvent for CO2 capture. The physicochemical properties (e.g., density, viscosity, electrical conductivity, surface tension, thermal decomposition temperature, glass transition point) of pure [bmim][tcm] were experimentally determined and successfully described using appropriate correlations. [Bmim][tcm] was found to be a low-viscous IL with a relatively high thermal stability (Tdecomp = 473.15 K). The solubilities of CO2 in [bmim][tcm] were measured at temperatures ranging from (288.15 to 363.15) K and a pressure range of (0.01 to 10) MPa using two different ...

Estimation of Normal Boiling Temperatures, Critical Properties, and Acentric Factors of Deep Eutectic Solvents

Abstract: Deep eutectic solvents (DESs) are novel solvents that have shown the ability to capture carbon dioxide from flue gases. Thermodynamic modeling is needed to validate the experimental vapor–liquid equilibria (VLE) of the CO2–DES systems. To establish thermodynamic models of these solvents, their critical properties must be estimated. In the present study, a combination of the modified Lydersen–Joback–Reid (LJR) method and the Lee–Kesler mixing rules has been applied to estimate the critical properties of 39 different DESs. Normal boiling temperatures and acentric factors have also been determined. The accuracy of this method has been tested by comparison of theoretical densities determined from the estimated critical properties with experimental values. Absolute deviations ranging from 0 % to 17.4 % were observed for the estimated density values. An overall average absolute deviation of 4.9 % was observed for the studied DESs. Absolute deviations for DESs consisting of aliphatic precursors ranged from 0 % t...

Removal of Cadmium(II) from Wastewater Using Novel Cadmium Ion-Imprinted Polymers

Abstract: Cadmium ion-imprinted polymers (Cd-IIP) were synthesized by precipitation polymerization using a complex of dithizone and cadmium as a template. The saturation adsorption capacity of the Cd-IIP is two times that of the nonimprinted polymers (Cd-NIP). Homogeneous binding sites are confirmed by the Langmuir isotherm. The adsorption kinetics fit a pseudo-second-order model well; and the adsorption equilibrium time is only approximately 20 min. The effect of coexisting ions on the Cd(II)-IIP and NIP were investigated by competing with Pb(II), Zn(II), Co(II), and Cu(II), and the ratio of relative selectivity coefficients was greater than 1.68. Thermodynamic parameters indicated that Cd(II) adsorption over IIP and NIP was a spontaneous and exothermic process. The enthalpy changes in different temperatures and adsorption energy are lower than −20.0 and 8 kJ/mol; respectively. These indicate that the adsorption process may be dominated by physisorption. The Cd-IIP was used for five cycles with a small decrease in...

Use of Carboxyl Functional Magnetite Nanoparticles as Potential Sorbents for the Removal of Heavy Metal Ions from Aqueous Solution

Abstract: In this work, carboxyl functionalized magnetite nanoparticles (CMNPs) are developed for the adsorption of Pb(II), Cd(II), and Cu(II). The characterization of CMNPs was performed by Fourier transform infrared spectroscopy, powder X-ray diffraction, and transmission electron microscopy. Studies show that the adsorption kinetics are found to follow the pseudo-second-order kinetic model. The experimental equilibrium adsorption data are fitted well to the Freundlich model. The maximum adsorption capacity at 25 °C could reach up to (74.63, 45.66, and 44.84) mg g–1 for Pb(II), Cd(II), and Cu(II), respectively. Thermodynamic analyses show that the adsorption is exothermic and spontaneous, and thermodynamic parameters, ΔG, ΔH, and ΔS, are calculated. In addition, CMNPs can be used as the recyclable adsorbent for the adsorption of Pb(II), Cd(II), and Cu(II) from aqueous solutions.

Experimental Investigation and Thermodynamic Modeling of CH4/N2 Adsorption on Zeolite 13X

Abstract: To implement an experimental study of CH4/N2 adsorption on Zeochem Co. zeolite 13X, a volumetric apparatus was utilized. In this regard, pure adsorption isotherms were measured at different temperatures [(273, 283, 303, 323, and 343) K] and pressures up to 10 bar, while binary data were collected at (303 and 323) K and different pressures and bulk gas phase molar fractions. Integral and differential thermodynamic consistency tests (TCT) were performed to validate the collected data and certify accuracy of the measurements. To have a thermodynamic view over the investigated system, thermodynamic functions such as enthalpy, entropy, surface potential, and Gibbs free energy were estimated numerically. Besides, the measured pure isotherms were regressed using different isotherm equations and the regressed parameters were applied to different models based on the thermodynamic theory of solutions, i.e., ideal adsorbed solution theory (IAST), vacancy solution models (VSM), and Peng–Robinson two-dimensional equat...

Thermophysical Properties of Glycols and Glymes

Abstract: Experimental data for density, viscosity, refractive index and sound speed of 11 glycols and glymes were measured in the temperature range between (283.15 and 373.15) K and at atmospheric pressure. The compounds evaluated include ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TriEG), tetraethylene glycol (TeEG), ethylene glycol ethyl ether (EGEE), diethylene glycol methyl ether (DEGME), diethylene glycol dimethyl ether (DEGDME), diethylene glycol ethyl ether (DEGEE), diethylene glycol diethyl ether (DEGDEE), triethylene glycol dimethyl ether (TriEGDME), and tetraethylene glycol dimethyl ether (TeEGDME). Additionally, derivative properties, such isobaric thermal expansion coefficient and isentropic compressibilities were also estimated and discussed. The compounds evaluated were selected to evaluate the impact of molecular structure changes on their thermophysical properties. Effects like the increase in the number of ethoxy groups, shown to lead to an increase of the density, molar vol...

Self-Diffusion in Molecular Fluids and Noble Gases: Available Data

Abstract: Experimental self-diffusivities of gases, vapors, and liquids obtained by means of tracer techniques and nuclear magnetic resonance are reviewed. The considered substances range from noble gases and simple diatomics (nitrogen, oxygen, carbon monoxide, etc.) to complex organic molecules, such as phenolphthalein dimethyl ether and 2-(α-methylbenzylamino)-5-nitropyridine, although polymers have not been included. Some comments on the applicability of neutron scattering to the determination of self-diffusion coefficients are also made. All the experimental results of the investigated systems are given as Supporting Information, whereas the references, temperatures, and pressures of these data and the main features of the measurement methods are compiled and classified.

Viscosity and Density of Aqueous Solutions of Carbon Dioxide at Temperatures from (274 to 449) K and at Pressures up to 100 MPa

Abstract: The viscosity and density of aqueous solutions of carbon dioxide having mole fractions of CO2 of 0.0086, 0.0168, and 0.0271 are reported. The measurements were made in the single-phase compressed liquid region at temperatures between (294 and 449) K at pressures up to 100 MPa; additional density measurements were also made at T = 274 K in the same pressure range. The viscosity was measured with a vibrating-wire viscometer while the density was measured by means of a vibrating U-tube densimeter; both were calibrated with pure water and either vacuum or ambient air. The density data have an expanded relative uncertainty of 0.07 % with a coverage factor of 2. From the raw data, the partial molar volume of CO2 in aqueous solution has been determined and correlated as an empirical function of temperature and pressure. When combined with the IAPWS-95 equation of state of pure water, this correlation represents the measured densities of under-saturated solutions of CO2 in water within ± 0.04 %. The viscosity dat...

Density, Refractive Index, and Speed of Sound of the Binary Mixture of 1-Butyl-3-methylimidazolium Tetrafluoroborate + N-Vinyl-2-pyrrolidinone from T = (298.15 to 323.15) K at Atmospheric Pressure

Abstract: Density (ρ), refractive index (nD), and speed of sound (u) values are measured for the binary mixture of 1-butyl-3-methylimidazolium tetrafluoroborate (1) and N-vinyl-2-pyrrolidinone (2) over the entire range of mole fractions at temperatures from T = (298.15 to 323.15) K under atmospheric pressure. Using the basic experimental data, various acoustic and thermodynamic parameters are calculated and are discussed in terms of molecular interactions between the present investigated binary system. The excess values are fitted to the Redlich–Kister polynomial equation to estimate the binary coefficients and standard deviation between the experimental and calculated values. Further, the molecular interactions in the binary mixture system are analyzed using the experimental FT-IR spectrum recorded at room temperature.

Are Laboratory-Formed Hydrate-Bearing Systems Analogous to Those in Nature?

Abstract: The intensive study of hydrate-bearing sandy sediments, a possible source of fossil energy for future generations, leads to an accumulation of information from field studies, laboratory studies, and modeling. This information is used to create conceptual models for hydrate deposit genesis helping to assess the value of laboratory experimental studies on artificially formed hydrate-bearing sediments. We present an experimental example on the simulation of hydrate formation from methane dissolved in water, which is assumed to be the most likely natural process for the genesis of highly concentrated hydrate in sandy sediments. Measurements of the concentration of dissolved methane, temperature, and electrical resistivity tomography are used to describe and characterize the hydrate formation process. It could be shown that the way in which hydrate forms in this laboratory experiment corresponds to the procedure assumed for natural scenarios. The main difference to nature is probably the high crystal growth ra...

Thermodynamics and Kinetics of Heavy Metals Adsorption on Silica Particles Chemically Modified by Conjugated β-Ketoenol Furan

Abstract: A novel adsorbent for heavy metals, functionalized with conjugated β-ketoenol Furan, was fabricated using a simple heterogeneous method. The adsorbent design (SiNFn) was well analyzed and characterized by the techniques of solid state 13C NMR, Fourier transform-infrared spectroscopy (FT-IR), elementary analysis, nitrogen adsorption–desorption isotherm, BET surface area, BJH pore sizes, and scanning electron microscopy (SEM). The new surface has good thermal stability determined by thermogravimetry curves analysis (TGA), and a good chemical stability investigated in various acidic and buffer solutions. The effect of various parameters on Cd(II), Cu(II), Zn(II), and Pb(II) adsorption, such as pH, concentration, temperature, competitive extraction, thermodynamics and kinetics studies, and extraction of metals from real water samples were investigated. The results indicated that the adsorption efficiency increases with increasing pH and follows pseudo-second-order kinetics. Adsorption was rapid as evidenced b...

Density of 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)amide and 1-Hexyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)amide over an Extended Pressure Range up to 250 MPa

Abstract: Densities of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([BMIM][Tf2N]) between (273 and 363) K over an extended pressure range up to 250 MPa and densities for 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([HMIM][Tf2N]) at 288.15 K to 175 MPa and between (273 and 363) K at 0.1 MPa are reported. The high-pressure densities were measured with a metal bellows volumometer, whereas the atmospheric pressure densities were determined with a vibrating tube densimeter. The overall uncertainties are estimated to be 0.02 % at atmospheric pressure and 0.1 % at higher pressures. The standard Tait equation of state with temperature dependent parameters B(T) and C(T) was used to represent the temperature and pressure dependences of the densities, with a standard uncertainty of 0.6 kg/m3 or 0.03 %. The isothermal compressibility, isobaric expansivity, and the internal pressure were obtained from differentiation of the equation of state, but as the calculation of the t...