For osmotic processes high flux of solvents combined with high rejection of solutes are necessary. TFC-membranes will be focused because the separation and support membranes are prepared separately, hence their influence on the performance of the two memb ranes and the total TFC-membrane will be studied separately.
The main objective is by focusing on the nanostructure of the two membranes, to synthesize novel and improved polymer membranes that fulfill technical, mechanical, chemical and economical deman ds for use in osmotic processes. Surface modifications of the two membranes will be studied.
1:To enhance the solvent flux through the separation membrane the nanolayerd structure resulting from interfacial polymerization will be studied with special focu s on having a completely hydrophilic layer against the support membrane.
Also coating processes developed at DCE and SINTEF will be studied.
By these processes the separation membranes will be crosslinked.
With a principle also developed at DCE and SINTEF , a controlled degree of swelling of the separation membrane may be achieved.
2:The rejection of ions by the separation membrane will be increased by attaching strong acids or bases to the surface.
3:Support membranes of about 0.1 mm thickness will be pr epared by mould polymerization giving porous, cross linked membranes with embedded reinforcement. This efficient process is developed at our laboratory and is based on earlier work at DCE and SINTEF. Advantages of this process are that a severe control of pore size and porosity are achieved and the surface porosity is expected to be the same as in bulk. The process gives an excellent opportunity to study how the nanostructure of the membranes influences the flow of solvent.
4: By surface modifications of the internal pores of the support membrane, the influence of the pore surface on solvent flow and concentration polarization will be studied.
5:The membranes' pore structure and fluxes will be determined.