Showing papers on "Binary system published in 2011"

Dye adsorption and desorption properties of Mentha pulegium in single and binary systems

Abstract: This article deals with the dye adsorption and desorption properties of Mentha pulegium (MP) from single and binary (mixture of dyes) systems. Direct Red 80 (DR80) and Acid Black 26 (AB26) were used as model dyes. The Fourier transform infrared (FTIR) was used to investigate the biosorbent characteristics. The effects of biosorbent dosage, contact time, dye concentration, salt, and pH on dye removal were studied. The biosorption isotherms, kinetics, and thermodynamic were studied. In addition, dye desorption was carried out to study adsorbent recovery. The results showed that the isotherm data of single and binary systems of dyes followed the Langmuir isotherm. The adsorption kinetic of the dyes was found to conform to a pseudosecond order kinetic model. Desorption tests showed maximum dye releasing of 97% for DR80 and 95% for AB26 in single system and 92% for DR80 and 94% for AB26 in binary system of dyes at pH 12. The thermodynamic data showed that the biosorption process is spontaneous, endothermic, and a physisorption reaction. It can be concluded that MP is an ecofriendly biosorbent to remove dyes from single and binary systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Interparticle forces in binary and ternary ordered powder mixes.

Abstract: An ultracentrifuge technique, previously described by Staniforth et al (1981), has been used to study the adhesion profiles of several binary and ternary ordered powder mixes of pharmaceutical interest. The adhesion profile of an ordered mix provides information about the proportion of drug powder adhering with different forces of attraction to the carrier excipient particle surface. The excipient particle size is shown to affect adhesion between the components of a binary ordered mix-recrystallized lactose formed more stable ordered mixes with drug powder when the carrier particle size was increased. Changes in the adhesion profile of each binary system on adding three different fine-powder excipients to form a ternary ordered mix are also examined. The physical properties of carrier particles and the charge interactions of a third powder component with previously formed binary ordered mixes, are found to influence the physical stability of ternary ordered mixes.

Transport Properties and Phase Behaviour in Binary and Ternary Ionic Liquid Electrolyte Systems of Interest in Lithium Batteries

Abstract: A binary ionic liquid (IL) system based on a common cation, N-methyl-N-propylpyrrolidinium (C(3) mpyr(+)), and either bis(trifluoromethanesulfonyl)imide (NTf(2) (-)) or bis(fluorosulfonyl) imide (FSI(-) as the anion is explored over its entire composition range. Phase behavior, determined by DSC, shows the presence of a eutectic temperature at 247 K and composition around an anion ratio of 2:1 (FSI(-) :NTf(2)(-)) with the phase diagram for this system proposed (under the thermal conditions used). Importantly for electrochemical devices, the single phase melting transition at the eutectic is well below ambient temperatures (247 K). To investigate the effect of such anion mixing on the lithium ion speciation, conductivity and PFG-NMR diffusion measurements were performed in both the binary IL system as well as the Li-NTf(2) -containing ternary system. The addition of the lithium salt to the mixed IL system resulted in a decrease in conductivity, as is commonly observed in the single-component IL systems. For a fixed lithium salt composition, both conductivity and ion diffusion have linear behaviour as a function of the anion ratio, however, the rate of change of the diffusion coefficient seems greater in the presence of lithium. From the application point of view, the addition of the FSI(-) to the NTf(2)(-) IL results in a considerable increase in lithium ion diffusivity at room temperature and no evidence of additional complex ion behaviour.

Ab initio molecular dynamics simulations of a binary system of ionic liquids

Abstract: This work presents first insights into the structural properties of a binary mixture of ionic liquids from the perspective of ab initio molecular dynamics simulations. Simulations were carried out for a one-to-one mixture of 1-ethyl-3-methyl-imidazolium thiocyanate and 1-ethyl-3-methyl-imidazolium chloride and compared to pure 1-ethyl-3-methyl-imidazolium thiocyanate.

A comparative study on Pb(II), Cd(II), Cu(II), Co(II) adsorption from single and binary aqueous solutions on additive assisted nano-structured goethite

Abstract: Development of low cost adsorbents for mitigation of toxic ions is one of the most important areas of research and development. Iron oxides especially in nano form have the potential for removing cations due to their structural properties. In the present work additive assisted nano structured goethite was synthesized at pH 3.0 and its cation adsorption behaviour was studied for Pb(II), Cd(II), Cu(II) and Co(II) from single and binary aqueous solutions. The contact time data for single cation adsorption followed pseudo second order kinetic model for all the four cations. The isothermic data was fitted to Langmuir and Freundlich models. The experimentally obtained maximum loading capacities were estimated as 109.2, 86.6, 29.15 and 37.25 mg/g of goethite for Pb(II), Co(II), Cd(II) and Cu(II) respectively from single cation containing solutions. Thermodynamic parameters were evaluated for the four metal ions. Adsorption behaviour from binary solutions was studied by keeping the concentration of Pb(II) at saturation concentration (500 mg/L) for its maximum uptake and varying the concentration of other metal ions (one at a time) in the range of 25 to 200 mg/L. The Pb(II) loading capacity increased in the presence of Cd(II) or Co(II) while it decreased in the presence of Cu(II) in the studied range of concentration variation. Maximum Pb(II) uptake was observed from Pb(II)-Cd(II) binary system (222 mg/L) with Pb II) and Cd(II) concentration as 500 and 200 mg/L respectively. An increase in the combined uptake capacities for Pb(II)-Cd(II) and Pb(II)-Co(II) binary systems were observed whereas a decrease was observed for Pb(II)-Cu(II) binary system. The synthesized goethite can be used effectively for cation removal from single/binary cation containing aqueous solutions. Keywords : Nano goethite; TEM, adsorption; cations; binary; kinetics International Journal of Engineering, Science and Technology , Vol. 2, No. 8, 2010, pp. 89-103

A mechanistic view of binary colloidal superlattice formation using DNA-directed interactions

Abstract: The use of grafted, single-stranded DNA oligomer brushes with engineered sequences to effect tunable interactions between colloidal particles has now been demonstrated experimentally in both nano- and microscale systems. The versatility of this technology is highly appealing for realizing self-assembly of complex structures. However, ambiguities remain regarding how operating conditions, such as the rate at which the system temperature is reduced, interact with the other system parameters to produce crystalline assemblies with particular structures and defect densities. In this paper, a computational analysis is presented for the crystallization of binary superlattice crystals comprised of sub-micron colloidal spheres using a realistic model for the DNA-mediated interactions. The binary system consists of two populations of identical spheres that differ only in the sequence of the DNA oligomers grafted onto their surfaces. Metropolis Monte Carlo simulations and perturbation theory for free energy estimation are used to construct a detailed mechanistic picture for binary superlattice formation. The analysis reveals several interesting features of this system, particularly the role of kinetics in dictating not only the quality of the superlattice crystals, but also their crystalline structure. Using the results presented here, we make connections to recent experimental findings in similar binary crystallization systems.

Densities, Viscosities, Speeds of Sound, FT-IR and 1H-NMR Studies of Binary Mixtures of n-Butyl Acetate with Ethanol, Propan-1-ol, Butan-1-ol and Pentan-1-ol at 298.15, 303.15, 308.15 and 313.15 K

Abstract: Densities, viscosities and speeds of sound of binary mixtures of ethanol, propan-1-ol, butan-1-ol and pentane-1-ol with n-butyl acetate have been measured over the entire range of composition at temperatures of 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure. From the experimental densities, viscosities and speeds of sound, the excess molar volumes V E, deviations in viscosity Δη, and deviations in isentropic compressibility Δκ S have been calculated. The excess molar volumes and deviations in isentropic compressibility are positive for all the binary systems studied over the whole composition, while deviations in viscosities are negative for all of the binary mixtures. The excess molar volumes, deviations in viscosity, and deviations in isentropic compressibility have been fitted to a Redlich–Kister type polynomial equation. FTIR and 1H-NMR studies of these mixtures are also reported.

Experimental measurement of vapor–liquid equilibrium for (trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) + propane (R290))

Abstract: The VLE data for the binary system of R1234ze(E) + R290 were measured with a recirculation method at four temperatures (258.150, 263.150, 273.150 and 283.150 K). The measured uncertainties of the temperature, pressure, and compositions are ±5 mK, ±0.0005 MPa, and ±0.005, respectively. All the experimental data were correlated by the Peng–Robinson (PR) EoS with the Huron–Vidal (HV) mixing rule involving the non-random two-liquid (NRTL) activity coefficient (PR–HV–NRTL) model. Azeotropic behavior can be found at the measured temperature range.

Densities and Viscosities of Binary Mixture of the Ionic Liquid Bis(2-hydroxyethyl)ammonium Propionate with Methanol, Ethanol, and 1-Propanol at T = (293.15, 303.15, 313.15, and 323.15) K and at P = 0.1 MPa

Abstract: In this work, density and viscosity were determined over the whole concentration range for the binary mixtures ionic liquid bis(2-hydroxyethyl)ammonium propionate [BHEAP] with methanol, ethanol, and 1-propanol at (293.15, 303.15, 313.15, and 323.15) K and 0.1 MPa. Excess molar volume and viscosity deviations for the binary system were calculated and well fitted to a Redlich−Kister equation.

Ta2O5–Y2O3–ZrO2 system: Experimental study and preliminary thermodynamic description

Abstract: Some aspects of stable and equilibrium phases in the Ta 2 O 5 –Y 2 O 3 –ZrO 2 system have been studied in this work. Phase stability of Ta 0.16 Y 0.16 Zr 0.68 O 2 and Ta 0.10 Y 0.10 Zr 0.80 O 2 has been studied by X-ray powder diffraction. A secondary phase segregation of YTaO 4 has been observed in both compositions below 1500 °C. However, once treated at 1500 °C, YTaO 4 phase disappears. The preliminary phase diagram of the Ta 2 O 5 –Y 2 O 3 –ZrO 2 system at 1200 °C and 1500 °C have been constructed using THERMOCALC package. Thermodynamic description is obtained by critically evaluating experimental data on the binary systems Y 2 O 3 –Ta 2 O 5 and Ta 2 O 5 –ZrO 2 . Binary system data have been combined and parameters for ternary tetragonal and cubic structures have been assessed to construct ternary phase diagram. Calculated isothermal section at 1200 °C is similar to 1500 °C. There is no change in the tetragonal solid solution region observed with temperature, which indicates the same equilibrium phases at 1500 °C and at 1200 °C.

Phase diagram and dissolution studies of the fenofibrate–acetylsalicylic acid system

Abstract: Enhancement of the dissolution rate of poorly soluble compounds through the formation of drug–drug eutectics was investigated using fenofibrate and acetylsalicylic acid. Solid–liquid equilibria in the system under study were investigated by differential scanning calorimetry (DSC). The phase diagram for the whole range of compositions was constructed. In addition, existence of a metastable polymorph of fenofibrate has been confirmed. The investigation has revealed that acetylsalicylic acid and fenofibrate form a simple eutectic mixture containing 0.958 mol fraction of fenofibrate at the eutectic point. Dissolution rate improvement of fenofibrate correlated with the phase diagram. The amount of fenofibrate released from the solid dispersions that contained fenofibrate as the eutectic mixture with acetylsalicylic acid was at least threefold higher compared to untreated fenofibrate.

Densities and Viscosities of [Bmim][PF6] and Binary Systems [Bmim][PF6] + Ethanol, [Bmim][PF6] + Benzene at Several Temperatures and Pressures: Determined by the Falling-Ball Method

Abstract: A falling-body viscometer was designed and manufactured to determine the densities and viscosities of liquids at high temperatures and pressures. The densities and viscosities for pure [bmim][PF6], [bmim][PF6] + ethanol, and [bmim][PF6] + benzene binary systems were determined in the temperature range of (313.2 to 413.2) K and in the pressure range of (0.1 to 25.0) MPa. The viscosities of [bmim][PF6] + ethanol, and [bmim][PF6] + benzene binary systems were correlated with temperature, pressure, and composition by correlation equations. The correlation coefficients (R) are 0.999 and 0.999 for [bmim][PF6] + ethanol and [bmim][PF6] + benzene systems, respectively.

Experimental and molecular modeling study of the three-phase behavior of (n-decane + carbon dioxide + water) at reservoir conditions.

Abstract: Knowledge of the phase behavior of mixtures of oil with carbon dioxide and water is essential for reservoir engineering, especially in the processes of enhanced oil recovery and geological storage of carbon dioxide. However, for a comprehensive understanding, the study of simpler systems needs to be completed. In this work the system (n-decane + carbon dioxide + water) was studied as a model (oil + carbon dioxide + water) mixture. To accomplish our aim, a new analytical apparatus to measure phase equilibria at high pressure was designed with maximum operating temperature and pressure of 423 K and 45 MPa, respectively. The equipment relies on recirculation of two coexisting phases using a two-channel magnetically operated micropump designed during this work, with sampling and online compositional analysis by gas chromatography. The apparatus has been validated by comparison with published isothermal vapor-liquid equilibrium data for the binary system (n-decane + carbon dioxide). New experimental data have been measured for the system (n-decane + carbon dioxide + water) under conditions of three-phase equilibria. Data for the three coexisting phases have been obtained on five isotherms at temperatures from 323 to 413 K and at pressures up to the point at which two of the phases become critical. The experimental work is complemented here with a theoretical effort in which we developed models for these molecules within the framework of the statistical associating fluid theory for potentials of variable range (SAFT-VR). The phase behavior of the three binary subsystems was calculated using this theory, and where applicable, a modification of the Hudson and McCoubrey combining rules was used to treat the systems predictively. The experimental data obtained for the ternary mixture are compared to the predictions of the theory. Furthermore, a detailed analysis of the ternary mixture is carried out based on comparison with available data for the constituent binary subsystems. In this way, we analyzed the observed effects on the solubility when the third component was added.

High Fill-Out, Extreme Mass Ratio Overcontact Binary Systems. X. The new discovered binary XY Leonis Minoris

Abstract: The new discovered short-period close binary star, XY LMi, was monitored photometrically since 2006. It is shown that the light curves are typical EW-type and show complete eclipses with an eclipse duration of about 80 minutes. By analyzing the complete B, V, R, and I light curves with the 2003 version of the W-D code, photometric solutions were determined. It is discovered that XY LMi is a high fill-out, extreme mass ratio overcontact binary system with a mass ratio of q=0.148 and a fill-out factor of f=74.1%, suggesting that it is on the late evolutionary stage of late-type tidal-locked binary stars. As observed in other overcontact binary stars, evidence for the presence of two dark spots on both components are given. Based on our 19 epoches of eclipse times, it is found that the orbital period of the overcontact binary is decreasing continuously at a rate of dP/dt=-1.67\times10^{-7}\,days/year, which may be caused by the mass transfer from the primary to the secondary or/and angular momentum loss via magnetic stellar wind. The decrease of the orbital period may result in the increase of the fill-out, and finally, it will evolve into a single rapid-rotation star when the fluid surface reaching the outer critical Roche Lobe.

Thermodynamic assessment of the Au–Ga binary system

Abstract: The Au–Ga binary system was assessed thermodynamically using the CALPHAD method through Thermo-calc ® software based on the critical review of the available experimental data from the published literature. The solution phases including liquid, fcc(Au), D0 24 and orthorhombic(Ga) are modeled by the substitutional solution model and their excess Gibbs energies are expressed with the Redlich–Kister polynomial. The intermetallic compounds, β - Au 7 Ga 2 , β ′ - Au 7 Ga 2 , γ - Au 7 Ga 3 , AuGa and AuGa 2 are treated as stoichiometric compounds. A set of self-consistent thermodynamic parameters obtained finally to describe the Gibbs energies of various phases in the Au–Ga binary system can be used to reproduce well the reported phase equilibria and thermodynamic properties data.

High fill-out, extreme mass ratio overcontact binary systems. x. the newly discovered binary xy leonis minoris

Abstract: The newly discovered short-period close binary star, XY LMi, has been monitored photometrically since 2006. Its light curves are typical EW-type light curves and show complete eclipses with durations of about 80 minutes. Photometric solutions were determined through an analysis of the complete B, V, R, and I light curves using the 2003 version of the Wilson-Devinney code. XY LMi is a high fill-out, extreme mass ratio overcontact binary system with a mass ratio of q = 0.148 and a fill-out factor of f = 74.1%, suggesting that it is in the late evolutionary stage of late-type tidal-locked binary stars. As observed in other overcontact binary stars, evidence for the presence of two dark spots on both components is given. Based on our 19 epochs of eclipse times, we found that the orbital period of the overcontact binary is decreasing continuously at a rate of dP/dt = -1.67 x 10(-7) days yr(-1), which may be caused by mass transfer from the primary to the secondary and/or angular momentum loss via magnetic stellar wind. The decrease of the orbital period may result in the increase of the fill-out, and finally, it will evolve into a single rapid-rotation star when the fluid surface reaches the outer critical Roche lobe.

Influence of Some Ionic Liquids Containing the Trifluoromethanesulfonate Anion on the Vapor–Liquid Equilibria of the Acetone + Methanol System

Abstract: Isobaric vapor–liquid equilibria (VLE) for the binary systems acetone + 1-butyl-3-ethylimidazolium trifluoromethanesulfonate ([beim][triflate]), methanol + [beim][triflate], acetone + 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([bmpyr][triflate]), and methanol + [bmpyr][triflate] as well as the VLE for the acetone + methanol + [beim][triflate] and acetone + methanol + [bmpyr][triflate] ternary systems have been obtained at 100 kPa using a recirculating still. The addition of both ionic liquids to the solvent mixtures produced an important salting-out effect, and the azeotrope tended to disappear for small amounts of ionic liquid. The experimental binary data sets were independently fitted with the electrolyte nonrandom two-liquid (NRTL) model, and the parameters of the Mock's model were estimated for each binary system. These parameters were used to predict the ternary VLE, which agreed very well with the experimental ones.