Metal-organic frameworks for gas adsorption

1. A method for the separation of carbon dioxide from a mixture, comprising contacting the mixture with a sorbent comprising a metal organic framework (MOF), wherein the MOF comprises:

a plurality of secondary building units (SBUs), each SBU comprising a repeating unit of one metal cation connected to another metal cation via a first moiety of an organic linker;

a layer of connected adjacent SBUs in which a second moiety of the linker in a first SBU is connected to a metal cation of an adjacent SBU, and

wherein adjacent layers are connected to each other via linker-to-linker bonding interactions; and

wherein each metal ion is selected from cobalt(II) ions, manganese(II) ions and nickel(II) ions, the organic linker is 5-aminoisophthalate, the first moiety is a carboxylate group and the second moiety is an amino group.

2. The method of claim 1 , wherein the linker to linker bonding interactions are non-covalent.

3. The method of claim 1 , wherein the linker to linker bonding interactions comprise hydrogen bonding interactions.

4. The method of claim 1 , wherein the linker to linker bonding interactions comprise carboxyl-carboxyl bonding interactions.

5. The method of claim 1 , wherein the mixture comprises anaesthetic gas, refrigerant or coolant gas, air, natural gas, liquefied petroleum gas, coal seam gas, syngas, flue gas, geothermal gas, or combinations thereof.

6. The method of claim 1 , wherein the mixture comprises any of the following, or a combination thereof: hydrogen sulphide (H 2 S), oxygen (O 2 ), nitrogen (N 2 ), hydrogen (H 2 ), helium, neon, argon, krypton, xenon, radon, ozone (O 3 ), carbon monoxide (CO), sulphur dioxide (SO 2 ), ammonia (NH 3 ), nitric oxide (NO), nitrous oxide (N 2 O), nitrogen dioxide (NO 2 ), water vapour, hydrocarbons (functionalised or non-functionalised), or derivatives thereof.

7. The method of claim 1 , wherein the sorbent further comprises a material selected from polymeric materials, membranes, resins, biomolecules, clays, ceramics, carbon, inorganic oxides, and a combination thereof.

8. A system for separating carbon dioxide from a mixture comprising:

a chamber having an inlet adapted to direct the mixture into the chamber; and

a sorbent comprising a metal organic framework (MOF) positioned within the chamber, wherein the MOF comprises:

a plurality of secondary building units (SBUs), each SBU comprising a repeating unit of one metal cation connected to another metal cation via a first moiety of an organic linker;

a layer of connected adjacent SBUs in which a second moiety of the organic linker in a first SBU is connected to a metal cation of an adjacent SBU,

wherein adjacent layers are connected to each other via linker-to-linker bonding interactions;

and wherein each metal ion is selected from cobalt(II) ions, manganese(II) ions and nickel(II) ions, the organic linker is 5-aminoisophthalate, the first moiety is a carboxylate group and the second moiety is an amino group.

9. The system of claim 8 , wherein the sorbent further comprises polymeric materials, membranes, resins, biomolecules, clays, ceramics, carbon, inorganic oxides, and a combination thereof.

10. The system of claim 8 , wherein the sorbent is positioned in an adsorption column.

11. The system of claim 8 , wherein the sorbent is positioned on a fixed bed.

12. The system of claim 8 , further comprising a pressure swing system for varying the pressure in the chamber.

13. The system of claim 8 , further comprising a temperature swing system for varying the temperature in the chamber.