MIXED MATRIX MEMBRANES WITH PYROLIZED CARBON SIEVE PARTICLES AND METHODS OF MAKING THE SAME

摘要

Mixed matrix polymer membranes capable of separating carbon dioxide from mixtures including carbon dioxide and methane, and processes for purifying methane using the membranes include a selective layer thickness of between about 1000 Angstroms to about 0.005 inch, that include discrete carbon-based molecular sieve particles with sizes of between about 0.5 microns to about 5.0 microns. The particles are formed by pyrolyzing a precursor polymer in the form of a powder or film. The pyrolyzed polymer is then ideally milled to desired small size particles. The preferred ratio of particles to polymer is about 0.25 to about 1.0 by volume. A preferred method for preparing the mixed matrix membrane is by dispersing the particles in a solvent, adding a small quantity of the desired polymer, or "sizing agent" to "size" or "prime" the particles, adding a polymer, casting a film of the polymer solution, and evaporating the solvent to form a mixed matrix membrane film. The polymer is preferably a rigid, glassy polymer, more preferably, with a glass transition temperature above about 150 DEG C. The mixed matrix membrane is preferably in the form of a dense film or a hollow fiber.