Membranes matrix method

Phase Inversion (Solution Precipitation). Phase inversion, also known as solution precipitation or polymer precipitation, is the most important asymmetric membrane preparation method. In this process, a clear polymer solution is precipitated into two phases a soHd polymer-rich phase that forms the matrix of the membrane, and a Hquid polymer-poor phase that forms the membrane pores. If precipitation is rapid, the pore-forming Hquid droplets tend to be small and the membranes formed are markedly asymmetric. If precipitation is slow, the pore-forming Hquid droplets tend to agglomerate while the casting solution is stiU fluid, so that the final pores are relatively large and the membrane stmcture is more symmetrical. Polymer precipitation from a solution can be achieved in several ways, such as cooling, solvent evaporation, precipitation by immersion in water, or imbibition of... 

Crosslinked and crosslinkable hollow fiber mixed matrix membrane and method of making the same. US Patent 6,755,900. 

The entrapment method of immobilization is based on the localization of an enzyme within a polymer membrane matrix. It is done in such a way as to retain biocatalyst, while allowing penetration of substrate. 

The present work is the first attempt to develop the methods of preparation of carbon membrane catalysts with metal nanoparticles in a carbon membrane matrix. 

Nguyen, RH. and G. Raasch, Transfer matrix method for the electrochemical impedance of inhomogeneous porous electrodes and membranes. Journal of Electroanalytical Chemistry, 1999. 460(18) pp. 63-79... 

Figure 1 (A) Carrier-bound immobilized enzymes of defined size and shape. Insoluble carriers vary in iheir geometric parameters. Different shapes and types of enzyme carrier are illustrated (a) bead, (b) fiber, (c) capsule, (d) film, and (e) membrane. (B) Methods used for immobilizing enzymes onto a spherical solid support matrix 1, physical absorption 2, covalent binding 3, electrostatic binding 4, intermolecular cross-linking 5, gel entrapment 6, chelation and/or metal binding. E, enzyme M, metal.

The characteristics of membrane employed as support for SLM preparation influence both flux and stability in principle, higher porosity, less thickness and lower tortuosity of membrane matrix provide a higher flux. On the other hand, a membrane support with a thin and less tortuous structure is not favorable in terms of stability. SLM stability can also be affected by the organic solvent used in the LM phase and the method of preparation (Yang et al., 2007). 

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