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Content available remote Enhancement of Supercritical Fluid Extraction in Membrane Cleaning Process by Addition of Organic Solvents
100%
Krzysztoforski J. , Krasiński A. , Henczka M. , Piątkiewicz W.
Chemical and Process Engineering
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2013
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tom 34
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nr 3
403-414
EN
In this study, the process of membrane cleaning by supercritical fluid extraction was investigated. Polypropylene microfiltration membranes, contaminated with oils, were treated in a batch process with a supercritical fluid (SCF). As extractant, pure supercritical carbon dioxide or supercritical carbon dioxide with admixtures of methanol, ethanol and isopropanol were used. Single-stage and multi-stage extraction was carried out and process efficiency was determined. The obtained results showed that addition of organic solvents significantly enhances the cleaning performance, which increases with increase of organic solvent concentration and decreases with increasing temperature. All three solvents showed a comparable effect of efficiency enhancement. The results confirmed that supercritical fluid extraction can be applied for polypropylene membrane cleaning.
2
Content available Enhancement of Supercritical Fluid Extraction in Membrane Cleaning Process by Addition of Organic Solvents
88%
Krzysztoforski J. , Krasiński A. , Henczka M. , Piątkiewicz W.
|
3
Content available Manufacturing and characterization of resorbable PLGA membranes for biomedical applications
88%
Krok M. , Ferreira C. , Fernandes S. , Kościelniak D. , Dobrzyński P. , Pamuła E.
Engineering of Biomaterials
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2011
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tom Vol. 14, no. 104
8--13
EN
Porous poly(L-lactide-co-glycolide) (PLGA) membranes were prepared by solvent-casting/porogen leaching method. Poly(ethylene-glycol) (PEG) with two molecular weights was used as a pore former. Mechanical properties of the membranes were analyzed in tensile test. Topography, pore size and surface roughness were characterized by atomic force microscopy on both sites of the membranes. PEG leached out percentage, thickness and wettability were also measured. Osteoblast-like cells were cultured on the membranes for 24 h and 6 days, and morphology, distribution and number of adhered cells as well as secretion of proteins and nitric oxide were measured. The results show that PEG molecular weight affected size and distribution of pores on both surfaces of the membranes. It resulted also in different mechanical characteristics of the membranes. In vitro experiments show that the membranes support adhesion and growth of osteoblast-like cells suggesting their usefulness for guided tissue regeneration (GTR).
4
Content available remote Modeling of ethylbenzene dehydrogenation in catalytic membrane reactor with porous membrane
88%
Shelepova E. V. , Vedyagin A. A. , Mishakov I. V. , Noskov A. S.
Catalysis for Sustainable Energy
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2014
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tom 2
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nr 1
EN
The modeling of ethylbenzene dehydrogenation in a catalytic membrane reactor has been carried out for porous membrane by means of two-dimensional, non-isothermal stationary mathematical model. A mathematical model of the catalytic membrane reactor was applied, in order to study the effects of transport properties of the porous membrane on process performance. The performed modeling of the heat and mass transfer processes within the porous membrane, allowed us to estimate the efficiency of its use in membrane reactors, in comparison with a dense membrane (with additional oxidation of the hydrogen in shell side). The use of a porous ceramic membrane was found to cause an increase of the ethylbenzene conversion at 600°C, up to 93 %, while the conversion in the case of conventional reactor was 67%. In this work, we defined the key parameter values of porous membrane (pore diameter and thickness) for ethylbenzene dehydrogenation in catalytic membrane reactor, at which the highest conversion of ethylbenzene and styrene selectivity can be reached.
5
Content available Enhancement of supercritical fluid extraction in membrane cleaning process by addition of organic solvents
75%
Krzysztoforski J. , Krasiński A. , Henczka M. , Piątkiewicz W.
Chemical and Process Engineering
|
2013
|
tom Vol. 34, nr 3
403--414
EN
In this study, the process of membrane cleaning by supercritical fluid extraction was investigated. Polypropylene microfiltration membranes, contaminated with oils, were treated in a batch process with a supercritical fluid (SCF). As extractant, pure supercritical carbon dioxide or supercritical carbon dioxide with admixtures of methanol, ethanol and isopropanol were used. Single-stage and multi-stage extraction was carried out and process efficiency was determined. The obtained results showed that addition of organic solvents significantly enhances the cleaning performance, which increases with increase of organic solvent concentration and decreases with increasing temperature. All three solvents showed a comparable effect of efficiency enhancement. The results confirmed that supercritical fluid extraction can be applied for polypropylene membrane cleaning.
6
Mechanistic approach to membrane mass transport processes (mini review)
75%
Kargol M.
Cellular and Molecular Biology Letters
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2002
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tom 07
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nr 4
EN
Since the physical interpretation of practical Kedem-Katchalsky equations is not clear, we consider an alternative, mechanistic approach to membrane transport generated by osmotic and hydraulic pressure. We study a porous membrane with randomly distributed pore sizes (radii). We postulate that the reflection coefficient (σp) of a single porę may equal 1 or 0 only. From this postulate we derive new (mechanistic) transport equations. Their advantage is in clear physical interpretation.
7
Content available remote Model of a catalytic membrane in pressure driven processes
75%
Trusek-Hołownia A.
Chemical and Process Engineering
|
2008
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tom Vol. 29, z. 3
727-743
EN
A model of a catalytic membrane with pressure-driven mass transport of a stream of reagents has been formulated. Parameters of the model equation are the Peclet number (Pe) and Damkohler number (Da) and the coefficient of substrate permeability through a semipermeable membrane ( S). A solution of the model is the substrate concentration in the stream leaving the enzymatic layer, i.e. in the permeate stream. Once the model had been positively verified, a model analysis of the presented bioreactor type was performed which enabled identification of the impact of particular process parameters on the process run. The model analysis covered two cases: complete and limited substrate permeabilities of the semipermeable membrane.
PL
Przedstawiono model matematyczny membrany katalitycznej z transportem masy reagentów wywołanym gradientem ciśnienia. Parametrami modelu są: liczba Pecleta (Pe), liczba Damkohlera (Da) oraz współczynnik przepuszczalności substratu przez membranę półprzepuszczalną ( . S). Rozwiązaniem modelu jest stężenie substratu w strumieniu permeatu. Po pozytywnej weryfikacji modelu przedstawiono analizę modelową obrazującą wpływ poszczególnych parametrów na przebieg procesu. Analiza ta obejmowała dwa przypadki: całkowitą oraz częściową przepuszczalność substratu przez półprzepuszczalną membranę.
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