Azeotropy Breaking in Refrigerant Blends with Ionic Liquids
Pages 1-7
V. Mazur, S. Haddad and D. Nikitin

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.01.1

Published: 17 March 2014

Abstract: The principal aim of this work is to study azeotropy breaking in the refrigerant blends with ionic liquids (IL). The global phase diagram approach is applied to correlate azeotropic data for binary mixtures based only on critical properties and acentric factor of the individual components in mixtures. Analytical expressions to predict azeotropy phenomena in terms of critical parameters of pure components and binary interaction parameters are given. The eventual azeotropy appearance in the refrigerant – IL blends is discussed and conclusion about highly improbable azeotropic blend formation for these systems is given. Global phase behavior of ionic liquid – industrial refrigerant blends is analyzed and possible III, IV and/or V types according to the classification scheme of Scott and van Konynenburg[1] are established. The azeotropy breaking in binary refrigerant mixtures with ionic liquid adding is predicted.

Anisotropic Properties of Mesogenic Surfactants with Ionic Liquid Core
Pages 8-14
Jinzhi Wu, Masanori Nata and Seiji Ujiie

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.01.2

Published: 17 March 2014

Abstract: Ionic mesogens (HI-n), constructed from imidazolium-functionalized azobenzenes with differential flexible spacers and a nitro polar terminal group, were synthesized. Their potential thermotropic liquid crystal properties were investigated bypolarizing optical microscopy (POM), differential scanning calorimetry (DSC) and temperature variable X-ray diffraction measurements. HI-n exhibited a smectic A fluid (SmA) phase by anisotropy through interactions between azobenzene units and ionic interactions. This SmA formation was observed by POM and DSC. In the SmA phase, focal conic fan textures were observed by POM under the crossed-Nicols. The perpendicular structure (homeotropic alignment) formed spontaneously in the SmA phase through physical adsorption of imidazolium ionic units upon a glass plate. In the SmA phase, HI-n exhibited the X-ray diffraction patterns consisting of sharp inner reflections, corresponding to the layer distance, and a broad outer reflection exhibiting a short range order within the smectic layer. It is expected that the SmA layer consists of the hydrophilic and hydrophobic sublayers. The hydrophilic sublayer was formed by an ionic aggregation of imidazolium and iodide ions. On the other hand, the hydrophobic sublayer was obtained by segregation from the hydrophilic sublayer.

It can be considered that HI-n are an anisotropic ionic liquid because the SmA state has a fluidity such as an ionic liquid. The ionic material shows the strong temperature dependence of an ionic interaction. The ionic interactions in the liquid crystal phase became weak gradually with increasing temperature, and the fluidity of the liquid crystal phase increase. HI-n dissolved in water. The HI-n water solution revealed a lyotropic smectic A anisotropic fluid.

‘Meyer-Neldel Rule’: True History of its Development and its Intimate Connection to Classical Thermodynamics
Pages 15-31
E.B. Starikov

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.01.3

Published: 17 March 2014

Abstract: The history of the Meyer-Neldel rule’s development and the initial collective efforts toward its comprehension have been described here. The whole story gives a nice occasion to trigger thorough analysis of the basic thermodynamic laws and looking for the true sense of the entropy notion.

Separation and Recovery of SiC Particles Discharged from Silicon Wafer Production Process
Pages 32-38
Junji Shibata and Norihiro Murayama

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.01.4

Published: 17 March 2014

Abstract: In the slicing process of silicon wafer from silicon single crystal, it has been the general way to cut silicon by wire saws with the lubricant mixture of silicon carbide, as SiC, particles and wrapping oil. After slicing the silicon single crystal, the waste liquor containing SiC and silicon powders is discharged from the process. The particle sizes of SiC and Si are about 10μm and 1μm, respectively and the weight ratio is about 9:1. The particles discharged from slicing waste liquor become the mixture of SiC and SiO₂, when the waste liquor is burned after treating the lubricant oil by a filter press. In terms of the minimization of wastes and environment, it is preferable to separate and recover the valuable SiC from SiO₂.

In order to solve the problem mentioned above, flotation method can be applied to accomplish the separation of SiC from SiO₂. The cationic surfactants of dodecyl-tri-methyl-ammonium chloride (abbreviated as DTMAC hereafter) and tri-methyl-octyl-ammonium chloride (abbreviated as TMOAC hereafter) were used in this study. The adsorption amount of surfactants on SiC and SiO₂ particles was measured. The flotation behaviors of SiC and SiO₂ were investigated by changing pH, gas flow rate and flotation time in the presence of DTMAC. The purity and yield of SiC were also discussed in the flotation process comprising of roughing, cleaning and scavenging steps. A series of flotation process for SiC gave the purity and yield of 99.7% and 96.7%, respectively.

Application of Polyacrylamide for Methylene Blue Removal from Aqueous Solutions
Pages 39-47
Hassan Zavvar Mousavi, Aisan Khaligh, Mahdi Behzad and Jalal Rahchamani

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.01.5

Published: 17 March 2014

Abstract: In this study the removal of methylene blue (MB) dye from aqueous solutions by polyacrylamide (PAA) as a potential adsorbent was reported. PAA was characterized using SEM and FTIR measurements. Batch adsorption experiments were performed as a function of the solution pH, contact time, solute concentration and temperature. Evaluation of the obtained data with isotherm studies indicated that the adsorption process was matched well with the Langmuir model. The maximum capacity of adsorbent for MB was 111.1 mg g⁻¹. Kinetic studies were carried out on various kinetic models and the pseudo-second order kinetic model was fitted very well with experimental data. Moreover, the thermodynamic parameters indicated that the adsorption reaction was endothermic and spontaneous process.