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Enhancement of supercritical fluid extraction in membrane cleaning process by addition of organic solvents

Krzysztoforski J., Krasiński A., Henczka M., Piątkiewicz W.

Chemical and Process Engineering

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2013

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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.

2

Manufacturing and characterization of resorbable PLGA membranes for biomedical applications

Krok M., Ferreira C., Fernandes S., Kościelniak D., Dobrzyński P., Pamuła E.

Engineering of Biomaterials

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2011

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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).

3

Model of a catalytic membrane in pressure driven processes

Trusek-Hołownia A.

Chemical and Process Engineering

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2008

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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.