Wyniki wyszukiwania - Biblioteka Nauki

1

VAPOUR PERMEATION STUDY OF WATER AND ETHANOL THROUGH CROSSLINKED CHITOSAN AND ALGINATE MEMBRANES

100%

Turczyn R. , Gnus M. , Dudek G. , Tórz A. , Łącka D. , Strzelewicz A. , Łapkowski M.

Progress on Chemistry and Application of Chitin and its Derivatives

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2015

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tom 20

281-288

EN

A vapour permeation of water and ethanol through homogenous chitosan and alginate membranes was investigated. The influence of the polymer matrix and crosslinking agents, and measurement protocol on the transport properties were discussed. The conducted experiments showed the greater separation factor, better stability and resistant to solvents for chemically crosslinked membranes. On the other hand, stronger association of the matrix, than the physical, caused decrease of vapour fluxes.

2

Application of pervaporation and vapor permeation in environmental protection

100%

Kujawski W.

Polish Journal of Environmental Studies

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2000

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tom 09

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nr 1

EN

A review concerning pervaporation and vapor permeation - membrane separation techniques used to separate liquid mixtures, is presented. Examples of polymers for membrane preparation as well as performance parameters of pervaporation and vapor permeation membranes are described. The second part of the paper presents applications of pervaporation and vapor permeation in environmental protection. At the present, liquid product mixtures must fulfill high purity requirements as well as effluents; therefore, they have to be concentrated or reconditioned. In the process of product-integrated environmental protection, liquid substances should be separated specifically from the mainstream, either to save raw materials, to prevent or to minimize the disposal of effluents, or to recycle by-products. Such completely or partly soluble fluid mixtures can be separated with membrane methods. Pervaporation and vapor permeation as the most well-known membrane processes for the separation of liquid and vapor mixtures allow a variety of possible application areas: i) dewatering of organic fluids like alcohols, ketones, ethers etc.; ii) separation of mixtures from narrow boiling temperatures to constant (azeotrop) boiling temperatures; iii) removal of organic pollutants from water and air streams; iv) separation of fermentation products; v) separation of organic-organic liquid mixtures.

3

INFLUENCE OF CHITOSAN MOLECULAR WEIGHT AND DEGREE OF DEACETYLATION ON MEMBRANE PHYSICOCHEMICAL AND SEPARATION PROPERTIES IN ETHANOL DEHYDRATION BY THE VAPOUR PERMEATION PROCESS

88%

Gnus M.

Progress on Chemistry and Application of Chitin and its Derivatives

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2020

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tom 25

79 - 93

EN

Membranes were prepared using three chitosans with different molecular weights and degrees of deacetylation. The influence of chitosan features on membrane physicochemical properties, i.e. degree of swelling, contact angle and tensile strength, as well as membrane separation properties in ethanol dehydration by the vapour permeation process are discussed. The conducted experiments showed that an increase in the chitosan molecular weight led to an increase in the membrane surface contact angle concomitant with a decrease in the material selectivity coefficient. On the other hand, an increase in the chitosan degree of deacetylation caused a reduction in ethanol and improved the water permeate flux. There was greater selectivity in the test process for membranes prepared from chitosan with the lowest molecular weight.

4

Procesy estryfikacji z udziałem procesów membranowych

63%

Kubaczka A. , Skrzypek J.

Chemik

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2004

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tom Vol. 57, nr 11

440-446

PL

Procesy separacji membranowej zostały zastosowane z powodzeniem w wielu technologiach zastępując dotychczasowe techniki separacji mieszanin. Ogromnym obszarem, w którym techniki te mogą znaleźć zastosowanie, są reakcje chemiczne. Tzw. reaktory membranowe to aparaty, w których membrana stanowi element konstrukcyjny reaktora lub reaktor połączony jest z modułem membranowym. Proces membranowy w obu przypadkach może być wykorzystany do separacji lub oczyszczania substratów lub produktów reakcji. Rozwiązania te nie tylko upraszczają instalacje, a tym samym obniżają koszty inwestycyjne, ale umożliwiają: zwiększenie wydajności i efektywności reaktorów, obniżenie zużycia energii a także podniesienie jakości (czystości) produktów. W publikacji omówiono istotę procesów estryfikacji oraz ich poziom techniczny i technologiczny. Przeanalizowano kilka przykładów połączenia reakcji estryfikacji z PV oraz VP i na podstawie wyników dotychczasowych badań zastanowiono się nad przyszłością takich rozwiązań. Ustalono, że kilkunastoprocentowy wzrost konwersji przy równoczesnym zmniejszeniu kosztów eksploatacyjnych i inwestycyjnych instalacji to argumenty, które zadecydują o wdrożeniu tych rozwiązań w przemyśle, w niezbyt odległym horyzoncie czasowym.

EN

Membrane-base separation processes have found broad application for a wide range of technology by successful substitution of the classical separation processes. The membrane separation techniques can be widespread by coupling them with chemical reactions. Membrane reactors can be in form of apparatus in which the membrane is a part of the reactor wall or end. The other solution that is used very often it is a connection of the reactor with the external membrane unit. The membrane process in both solutions is used for separation or purification of reactions products. The integration of the chemical reaction with membrane separation process offers advantages not only in terms of system simplification and most likely lower capital cost, but also yield improvement and selectivity enhancement. In the present review a basic description of esterification processes are given and their actual technical level is outlined. Further, basing on few examples of previous experimental results of coupling esterifications with pervaporation and vapour permeation the future of such solutions was analysed. It was shown that esters yield can be significantly increased together with reduction of the operating and investment costs. Thus, we should observe a growing number of industrial applications in the nearest future.

5

Membrane distillation - examples of applications in technology and environmental protection

63%

Tomaszewska M.

Polish Journal of Environmental Studies

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2000

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tom 09

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nr 1

EN

This paper presents membrane distillation (MD), a separation process based on evaporation through pores of a hydrophobic membrane. Different configurations of the process were considered. Membrane properties, transport phenomena through the membranes, and module designs have been discussed. Applications of MD in water and wastewater treatment as well as in the food industry have been presented. The concentration of sulfuric acid solution obtained after extraction of apatite phosphogypsum by MD, in order to recover lanthane compounds has been presented. The possibility of recovery of HO from metal pickling solutions by MD has been shown.

6

Vapour and gas permeation across porous membranes - membrane distillation

51%

Tomaszewska M.

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tom Vol. 5, nr 2

26-32

EN

The principle of membrane distillation was presented. The different configurations of the process and necessary properties of MD membranes were described. Mass and heat transport during membrane distillation were considered. Applications of the membrane distillation for water and wastewater treatment have been shown.