Sharif Digital Repository

New experimental results are presented for the solubility of carbon dioxide, hydrogen sulfide in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]) at temperatures range from (303.15 to 353.15) K and pressures up to about 2 MPa. The solubility of the mixture of CO2/H2S in [C8mim][PF6] under various feed compositions were also measured at temperatures of (303.15, 323.15 and 343.15) K and the pressure up to 1 MPa. The solubility of carbon dioxide and hydrogen sulfide increased with increasing pressure and decreased with increasing temperature and the solubility of H2S is about three times that of CO2 in the particular ionic liquid studied. The measured data were... 

The formation constants for 1:1 molecular complex formation between water-soluble cobalt(II) tetradentate Schiff base complex, disodium[{bis(4- methoxy-5-sulfo-salicylaldehyde)-4,5-dimethyl-o-phenylenediiminato}cobalt(II)], Na2[Co(SO3-4-meosal-4,5-dmophen)], and nucleotides, adenosine-5′-triphosphate (ATP) and cytidine-5′-triphosphate (CTP), in mixed solvent systems of ethanol and water with different volume fractions of ethanol and water have been determined spectrophotometrically at constant ionic strength (I = 0.2 mol dm-3 NaClO4) and temperature 278 K. Trends in the values of formation constants according to the volume fractions of ethanol and water in ethanol and water mixed solvent... 

With over 8 million inhabitants and 4 million motor vehicles on the streets, Tehran is one of the most crowded and polluted cities in the Middle East. Frequent exceedances of national daily PM2.5 limit have been reported in this city during the last decade, yet, the chemical composition and sources of fine particles are poorly determined. In the present study, 24-hour PM2.5 samples were collected at two urban sites during two separate campaigns, a one-year period from 2014 to 2015 and another three-month period at the beginning of 2017. Concentrations of organic carbon (OC), elemental carbon (EC), inorganic ions, trace metals and specific organic molecular markers were measured by chemical... 

Homopolymer hydrogel of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and its nanocomposite counterpart were prepared to study their swelling properties. The hydrogels showed ability to absorb and retain electrolytes as well as binary mixtures of water and organic solvents (i.e., methanol, ethanol, acetone, ethylene glycol (EG), polyethylene glycol, N-methyl-2-pyrrolidone (NMP), and dimethylsulfoxide (DMSO). The nanocomposite gel exhibited lower swelling in all solvent compositions in comparison with non-composite gel. Unlike conventional acrylic acid-based hydrogels, the poly(AMPS) gels showed superabsorbing capacity in pure ethanol, methanol, EG, DMSO and NMP. Meanwhile, swelling... 

Classical molecular dynamics simulations are used to compute the solvation free energy of two pharmaceutical solids, namely ibuprofen and acetaminophen in carbon dioxide (CO2), over the density range of interest in supercritical processes. In order to examine the influence of the solvent model on the resulting free energies, three popular CO2 models (Zhang, EPM2, and TraPPE) are studied. Relatively large discrepancies for the solvation free energy exist between these CO2 models, suggesting that the former is sensitive to the different balances between dispersive and electrostatic forces used in these models. In particular, for the solvation of the highly polar (dipole moment of ∼5.2 Debye)... 

The mononuclear complex [Mn(tptz)(CH3COO)(OH2)2]NO3 (1) was investigated by electrospray ionization mass spectrometry in aqueous solution at pH 4.5. Electrospray ionization mass spectrometry shows that mononuclear and dinuclear manganese cationic species are present in solution, probably in equilibrium with neutral 1. An experiment showed that the most important reaction in the presence of oxone (2KHSO5·KHSO4·K2SO4) is decoordination  

Copper phthalocyanine can effectively act as alternative small molecule hole transporting material in perovskite solar cells. In order to produce solution processed devices, a soluble copper phtalocyanine has been synthesized by n-butyl substitution and it was compared to commercially available tert-butyl substituted copper phthalocyanine. It was found that the configuration of the butyl chain plays a very important role in film conductivity and in the subsequent efficiency of solar cells, n-bytyl derivative being the most effective hole transporter. Such a result is due to the fact that n-butyl derivative allows better packing of the molecules in the film and stronger π-π interaction  

The solubility of hydrogen sulfide gas in ionic liquids (ILs) 1-ethyl-3-methylimidazolium hexafluorophosphate ([emim][PF6]) at temperatures from (333.15 to 363.15) K and 1-ethyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide ([emim][Tf2N]) at temperatures ranging from (303.15 to 353.15) K and pressures up to about 2.0 MPa was measured using a volumetric based static apparatus. The solubility data were correlated using two models: the Krichevsky - Kasarnovsky (KK) equation, and the extended Henry's law combined with the Pitzer's virial expansion for the excess Gibbs energy. Henry's law constants (at zero pressure) were obtained at different temperatures from the obtained experimental... 

The solubility of hydrogen sulphide in three ionic liquids, viz. 1-hexyl-3-methylilmidazolium hexafluorophosphate ([hmim][PF6]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF4]), and 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([hmim][Tf2N]), at temperatures ranging from 303.15 K to 343.15 K and pressures up to 1.1 MPa were determined. The solubility values were correlated using the Krichevsky-Kasarnovsky equation and Henry's constants were obtained at different temperatures. Partial molar thermodynamic functions of solvation such as standard Gibbs free energy, enthalpy, and entropy were calculated from the solubility results. Comparison of the values obtained... 

The solubility of hydrogen sulfide in three ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf 2N]), at temperatures ranging from (303.15 to 343.15) K and pressures up to 1 MPa was determined. The solubility data were correlated using the Krichevsky-Kasarnovsky equation, and Henry's law constants at different temperatures were obtained. From the solubility data, the partial molar thermodynamic functions of solution such as Gibbs energy, enthalpy, and entropy were calculated. Comparison showed that the solubility of H2S in these... 

The solubility of hydrogen sulfide in a series of 1-(2-hydroxyethyl)-3-methylimidazolium ([HOemim]+)-based ionic liquids (ILs) containing different anions, viz. hexafluorophosphate ([PF6]-), trifluoromethanesulfonate ([OTf]-), and bis-(trifluoromethyl)sulfonylimide ([Tf2N]-) at temperatures ranging from 303.15 to 353.15K and pressures of up to about 1.8MPa was measured by a volumetric based static apparatus. The solubility data were correlated using two models: (1) the Krichevsky-Kasarnovsky equation and (2) the extended Henry's law combined with the Pitzer's virial expansion for the excess Gibbs energy. Henry's law constants (at zero pressure) in mole-fraction and molality scales were... 

The solubility of carbon dioxide in a series of 1-(2-hydroxyethyl)-3-methylimidazolium ([hemim]+) based ionic liquids (ILs) with different anions, viz. hexafluorophosphate ([PF6]-), trifluoromethanesulfonate ([OTf]-), and bis-(trifluoromethyl)sulfonylimide ([Tf2N]-) at temperatures ranging from 303.15 K to 353.15 K and pressures up to 1.3 MPa were determined. The solubility data were correlated using the Krichevsky-Kasarnovsky equation and Henry's law constants were obtained at different temperatures. Using the solubility data, the partial molar thermodynamic functions of solution such as Gibbs free energy, enthalpy, and entropy were calculated. Comparison showed that the solubility of CO2... 

The solubility of carbon dioxide and hydrogen sulfide gases in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([C2mim][OTf]) was measured at temperatures from (303.15-353.15) K and pressures up to about 3.0 MPa. The Henry's law constants were determined from the new experimental data, which in turn were used to derive the change of some thermodynamic functions of dissolution of the gases in that particular ionic liquid. The new experimental data were correlated by a combination of the extended Henry's law and Pitzer's model for the excess Gibbs energy. The average relative percent deviation (ARD%) of correlated molality values from experimental data are within... 

Supercritical fluid extraction is a new technology that could be effectively used to treat oil-contaminated drill cuttings generated during drilling for oil and gas. In this work, the solubility of oil-contaminated drill cuttings in supercritical carbon dioxide is obtained by an experimental flow type apparatus. The solubility was measured at 200 bar pressure, over a temperature range of 55-79.5°C. The measured solubility and experimental data for oil in drill cuttings were correlated using the PC-SAFT, PR and SRK EOS models, without any adjustable parameters. Average absolute derivations of less than 15.1 %, 98.7 %, and 99.3 % are achieved between predicted and experimental values for the... 

The solubility of acetaminophen in SuperCritical-Carbon Dioxide (SC- CO 2) with and without menthol as a cosolvent was measured at various temperatures (313, 328 and 343) K, and within pressures ranging from (10 to 25) MPa. It should be stated that the cosolvent, menthol, has chiral isomers with different melting points. Therefore, the effects of both menthol (I) with a lower melting point and menthol (II) with a higher melting point, as cosolvents on the solubility of acetaminophen in SC- CO 2, were studied. The experimental data collected in this work were obtained using a static flow apparatus. The experiments were replicated at least three times and the data reported are the average of... 

In the present study, the tri-layer nanofibers were synthesized via triaxial electrospinning process to control the sustained delivery of Doxorubicin (DOX), Paclitaxel (PTX) and 5- fluorouracil (5-FU) anticancer drugs from nanofibers. The 5-FU molecules were incorporated into the core solution (chitosan/polyvinyl alcohol (CS/PVA)) to fabricate the CS/PVA/5-FU inner layer of nanofibers. The intermediate layer was prepared from poly(lactic acid)/chitosan (PLA/CS) nanofibers. The DOX and PTX molecules were initially loaded into the g-C3N4 nanosheets and following were incorporated into the PLA/CS solution to fabricate the outer layer of nanofibers. The synthesized nanosheets and nanofibers were... 

Blood oxygenation is the main performance characteristic of capillary membrane oxygenators (CMOs). Handling of natural blood in in vitro investigations of CMOs is quite complex and time-consuming. Since the conventional blood analog fluids (e.g. water/glycerol) lack a substance with an affinity to capture oxygen comparable to hemoglobin's affinity, in this study a novel approach using modified sulfite solution is proposed to address this challenge. The solution comprises sodium sulfite as a component, simulating the role of hemoglobin in blood oxygenation. This approach is validated by OTR (oxygen transfer rate) measured using native porcine blood, in two types of commercially available... 

Supercritical fluid extraction (SFE) is a relatively new separation technique that has received much attention in recent years. This process is an alternative to distillation or liquid extraction. Its main advantage over the conventional ones is that the dissolved extract may be completely separated from the supercritical fluid simply by decreasing the pressure. In recent years considerable effort has been devoted to the measurement of equilibrium solubility data for solids in supercritical fluids. A coal tar distillate, anthracene oil, which contains 34.46 mass-% phenanthrene, 33.8 mass-% anthracene, 13.89 mass-% carbazole and other impurities, was used as the model mixture. In this study,... 

Clay liners are widely used as porous membrane barriers to control solute transport and to prevent the leakage of leachate both in horizontal and vertical flow scenarios, such as the isolated base and ramps of sanitary landfills. Despite the primary importance of saturated hydraulic conductivity in a reliable simulation of fluid flow through clay barriers, there is no model to predict hydraulic conductivity of clayey soils permeated with saline aqueous solutions because most of the current models were developed for pure water. Therefore, the main motivation behind this study is to derive semi-empirical models for simulating the hydraulic conductivity of clayey soils in the presence of... 

Polycrystalline (Pr1-x Bax)Ba2Cu 3O7-δ samples (0.0 ≤ x ≤ 0.6) is prepared by the standard solid state reaction technique. X-ray measurements confirm the formation of the 123 phase for x ≤ 0.3, but for 0.4 ≤ x ≤ 0.6, due to the solubility limit, the 123 phase is not a dominant phase. Resistivity measurements show the increasing of resistivity with the increase of Ba-doping up to about x=0.08, and then decreases in the 123 phase up to x = 0.3. There is no observation of superconducting state in our samples, but we observe the sharp decrease of resistivity for x>0.1, which is related to possible superconductivity in Pr123 system by Ba-doping. It is concluded that the Pr/Ba disorder has...