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Separation of Carbon Dioxide from Methane by Ionic Liquid Membrane
Kárászová, Magda ; Izák, Pavel
Work deals with ionic liquid membranes for separation of carbon dioxide and methane. Main advantage of ionic liquid is negligible vapor pressure and low chemical reactivity. [1]. Selectivity of liquid membranes is given by different solubility of separated gases in chosen liquid. Carbon dioxide is twenty times more soluble in used ionic liquid than methane. Membrane used for separation consisted of porous PVDF and ionic liquid [emim][Tf2N]. Permeability of pure gases and model mixtures through the membrane was tested. Ideal selectivity of the membranes for CO2/CH4 mixture was found to be 22. Permeability of pure gases does was only about 10% higher than permeability of mixed gases. The membrane may be applied for purification of biogas.
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Scaling Laws for Polymers in Dissipative Particle Dynamics Revised
Posel, Z. ; Lísal, Martin
We present here a systematic study of dynamic behavior for polymer (PE) melt by means of Dissipative Particle Dynamics (DPD). We used DPD spring potential between adjacent segments. By changing various parameters related to spring potential like stiffness k, equilibrium distance r0 and parameters related to dynamic behavior like friction coefficient γ presented in dissipation force we tested their influence on scaling laws. We also compared these scaling laws obtained from our simulations with predictions from Rouse theory.
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Vapor–Liquid Equilibrium in Diluted Polymer + Toluene Systems
Bogdanić, Grozdana ; Wichterle, Ivan
Vapor–liquid equilibrium data were determined for five polymer plus toluene systems at isothermal conditions between 60 and 100 oC. Polymers comprise copolymers and terpolymers of octadecyl acrylate, acrylic acid, styrene, and 1-vinyl-2-pyrrolidone because of their practical importance as flow improvers for crude oil and/or derivatives. All-glass micro-ebulliometer with circulation of liquid phase was used for measurement of total pressure over polymer + toluene mixtures. Two predictive group contribution models (the Entropic–Free Volume and the Group Contribution–Flory) were applied to estimate phase behavior of two polymer solutions; good agreement with experimental data was achieved.
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Critical Notes on Heterogeneous Photocatalysis on TiO2 Photocatalysts
Klusoň, Petr ; Hejda, S.
In our recent works we described different types of titania based materials used as either colloids or thin films. These were functionally characterized in photo-induced electrochemical measurements and/or in photocatalytic oxidations. Special attention was paid to the effect of organized internal structure induced by templating principles as an alternative to plasma enhanced physical methods. Considerable work has also been undertaken on research of porphyrine based photoactive macromolecules, which are efficient producers of singlet oxygen species upon well defined illumination.
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Processes of Nanoparticle Formation in Low Temperature Plasma
Brožek, V. ; Mastný, L. ; Moravec, Pavel ; Neufuss, Karel ; Ondráček, Jakub ; Ždímal, Vladimír
This work describes the synthesis of nanoparticles during interaction of several different metals (Ag) or their respective oxides (TiO2, Cr2O3) with oxygen-hydrogen plasma having temperatures above 25000 K. Resulting nanoparticles and/or their aggregates in the size range of 25-300 nm were deposited on metallic targets and/or trapped in the water filters and separated using ultra-centrifugal apparatus. The aerosol spectrometer SMPS 3936 (scanning mobility particle sizer) was used to study the particle size distribution of generated nanoparticles in the size range 14 – 700 nm. In order to extend the measured particle size range towards larger sizes, the APS 3321 spectrometer (aerodynamic particle sizer) with the size range 500-20000 nm was used simultaneously. Both spectrometers were set-up to sample with three minute time resolution. Process conditions and production of inorganic nanoparticles of defined composition are discussed in this work.
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AWS Viscometry – Principles and Applications
Wein, Ondřej
Quantitative identification of Apparent wall slip (AWS) effect, accompanying the flow of colloidal dispersions in confined geometries, requires a specific modification of common viscometric methods. Essential distinction between common and AWS viscometry is outlined – including theoretical background, calibration, data acquisition, and downstream data treatment – and demonstrated for a class of rotational viscometers.
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Rheology of high viscous food substances
Štern, Petr ; Vlasák, Pavel
Rheological properties of high viscous food substances, mainly of animal origin, greatly influenced their preparation, homogenization and processing. By collagen substances were studied the complex of rheological properties by their processing. We have determined, that the viscoelasticity have the bigger influence that dynamic viscosity.
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