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Elimination of selected anions and cations from water by means of the Donnan dialysis

Wiśniewski J. A., Kabsch-Korbutowicz M.

Environment Protection Engineering

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2017

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Vol. 43, nr 3

189--205

EN

The usefulness of the Donnan dialysis has been assessed for the elimination of harmful (bromide, bromate and nitrate) or troublesome (calcium and magnesium) ions from water. The rate and efficiency of ion exchange were examined. For anion removal Selemion AM V or Neosepta ACS membranes were used while for cation removal - Neosepta CMX or Selemion CMV ones. The influence of membrane properties and salt concentration in the receiver was investigated.

2

Retention of mycoestrogens in nanofiltration. Impact of feed water chemistry, membrane properties and operating process conditions

Dudziak M.

Environment Protection Engineering

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2012

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Vol. 38, nr 2

5--17

EN

The membrane process, i.e. nanofiltration, was considered a method for removal of mycoestrogens, compounds recently identified in aqueous environment, from water. The study was focused on the determination of the separation mechanism and on the possibility of removal of mycoestrogens in the applied process. Retention of zearalenone and α-zearalenol was investigated depending on the water matrix composition, the membrane applied, filtration mode and operating conditions of the process. As removed mycoestrogens reveal hydrophobic character, the separation mechanisms is based on the adsorption. Retention of those compounds is also dependent on the membrane type and the filtration mode. The highest effectiveness of mycoestrogens removal was obtained for cellulose membrane (CK), which characterized the highest values of the contact angle and the degree of NaCl removal in comparison with other composite membranes applied. Additionally, the CK membrane showed the highest ability to adsorb investigated micropollutants. However, the variation of retention of mycoestrogens was observed as the membrane surface was modified by inorganic and/or organic substances present in filtrated water. The degree of removal of mycoestrogens during nanofiltration exceeded 81% and considering the effectiveness and the capacity of the process, the cross-flow mode should be applied.

3

Simplifying assumptions and the scope of application of lipid membrane models

Kubica K.

Bio-Algorithms and Med-Systems

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2011

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Vol. 7, no. 2

13--16

EN

Biological membranes are components of the cell – the basic unit of life. Their structure originates from amphiphilic properties of lipid molecules ( the major constituent of biological membranes) which when surrounded by water spontaneously form organized structures that include bilayers. A bilayer created purely out of lipid molecules is used as a physical model of biological membranes on which one can study biological processes associated with their lipid phase. These may include: passive transport, formation and decomposition of domains, phase transitions and formation of pores influenced by an external electric field. Experiments on lipid bilayer coupled with studies of its mathematical models enable to gain an understanding of the aforementioned biological membrane phenomena at a molecular level. A mathematical model is characterized by a set of simplifying assumptions which determines its application. By developing a simple model that only takes into account the structure of the hydrophobic lipid molecules, we were able to observe phases of various density corresponding to temperature changes. Expanding the model by including the polar parts of lipid molecules expressed via a surface pressure multiplied by a surface area per one molecule increased its range of research. This assumption, did not allow capturing some of the factors such as ionic strength or a presence of water molecules. Supplementing the model with new assumptions increased its application. The extended model allowed additionally tracking changes in the membrane influenced by biologically active amphiphilic compounds as well as examining the process of electroporation.