Liquid composite compositions using non-volatile liquids and nanoparticles and uses thereof

A membrane for separating gases, comprising:

• a liquid composite composition comprising:
• i) a non-volatile liquid;
• and
• ii) nanoparticles, said nanoparticles each having at least one dimension less than 25 nm and being dispersed individually in the liquid composition, and wherein the nanoparticles have a surface that prevents substantial aggregation of the nanoparticles in the presence of the non-volatile liquid, and the liquid composite composition contains at least 20 wt. % of the dispersed nanoparticles.