Metal-containing sorbents for nitrogen-containing compounds
Metal-containing sorbent materials are provided, methods of making the metal-containing sorbent materials, methods of using the metal-containing sorbent materials, and metal complex-containing composite materials resulting from the sorption of basic, nitrogen-containing compounds on the metal-containing sorbent materials are provided. The sorbent materials are prepared by incorporating divalent metals into a precursor material that is formed by treating a porous siliceous material having mesopores with a silane or disilazane surface treatment agent. The metal-containing sorbent materials can be used to capture basic, nitrogen-containing compounds having a molecular weight no greater than 150 grams/mole.
1. A metal-containing sorbent comprising:
a) a precursor comprising a reaction product of a mixture comprising
1) a porous siliceous material having mesopores; and
2) a surface treatment agent in an amount in a range of 0.1 to 4.5 mmoles per gram of the porous siliceous material, the surface treatment agent comprising
(a) a silane of Formula (I)
R 1 —Si(R 2 ) 3-x (R 3 ) x (I)
wherein
R 1 is a hydrocarbon or fluorinated hydrocarbon group;
R 2 is a hydrolyzable group;
R 3 is a non-hydrolyzable group;
x in an integer equal to 0, 1, or 2; or
(b) a disilazane of Formula (II)
(R 4 ) 3 —Si—NH—Si(R 4 ) 3 (II)
wherein each R 4 is a hydrocarbon group; or
(c) a mixture of the silane of Formula (I) and the disilazane of Formula (II); and
b) a divalent metal incorporated into the precursor in an amount equal to at least 54 weight percent based on the total weight of the sorbent.
2. The metal-containing sorbent of claim 1 , wherein the porous siliceous material has pores and wherein at least 50 volume percent of the pores are mesopores.
3. The metal-containing sorbent of claim 1 , wherein the amount of the divalent metal incorporated into the precursor is in a range of 54- to 50 weight percent based on the total weight of the sorbent.
4. The metal-containing sorbent of claim 1 , wherein the divalent metal is from a Group 2 metal or a Group 6 to 12 metal of the IUPAC Periodic Table of Elements.
5. The metal-containing sorbent of claim 1 , wherein the divalent metal is divalent zinc or copper.
6. The metal-containing sorbent of claim 1 , wherein the sorbent further comprises an acid-base indicator incorporated into the precursor.
7. A composite comprising:
a) a precursor comprising a reaction product of a mixture comprising
1) a porous siliceous material having mesopores; and
2) a surface treatment agent in an amount in a range of 0.1 to 4.5 mmoles per gram of the porous siliceous material, the surface treatment agent comprising
(a) a silane of Formula (I)
R 1 —Si(R 2 ) 3-x (R 3 ) x (I)
wherein
R 1 is a hydrocarbon or fluorinated hydrocarbon group;
R 2 is a hydrolyzable group;
R 3 is a non-hydrolyzable group;
x is an integer equal to 0, 1, or 2; or
(b) a disilazane of Formula (II)
(R 4 ) 3 —Si—NH—Si(R 4 ) 3 (II)
wherein each R 4 is a hydrocarbon group; or
(c) a mixture of the silane of Formula (I) and the disilazane of Formula (II); and
b) a metal complex incorporated into the precursor, wherein the metal complex comprises a reaction product of
1) a divalent metal; and
2) at least one basic, nitrogen-containing compound,
wherein the divalent metal is present in an amount equal to at least 5 weight percent based on a total weight of the composite.
8. The composite of claim 7 , wherein the porous siliceous material has pores and wherein at least 50 volume percent of the pores are mesopores.
9. The composite of claim 7 , wherein the composite further comprises divalent metal that is not in the form of the metal complex.
10. The composite of claim 7 , wherein the total amount of divalent metal is in a range of 5 to 50 weight percent based on a total weight of the composite.
11. The composite of claim 7 , wherein the basic, nitrogen-containing compound has a molecular weight no greater than 150 grams/mole.
12. The composite of claim 7 , wherein the basic, nitrogen-containing compound is ammonia, a hydrazine compound, an amine compound, or a nitrogen-containing heterocyclic compound.
13. A method of capturing a basic, nitrogen-containing compound, the method comprising:
a) providing a metal-containing sorbent according to claim 1 ; and
b) exposing the metal-containing sorbent to a basic, nitrogen-containing compound to form a metal complex-containing composite.
14. A method of preparing a metal-containing sorbent, the method comprising:
a) providing a porous siliceous material having mesopores;
b) treating the porous siliceous material with a surface treatment agent to form a precursor, wherein treating comprises adding 0.1 to 4.5 mmoles of the surface treatment agent per gram of the porous siliceous material, the surface treatment agent comprising
1) a silane of Formula (I)
R 1 —Si(R 2 ) 3-x (R 3 ) x (I)
wherein
R 1 is a hydrocarbon or fluorinated hydrocarbon group;
R 2 is a hydrolyzable group;
R 3 is a non-hydrolyzable group;
x is an integer equal to 0, 1, or 2; or
2) a disilazane of Formula (II)
(R 4 ) 3 —Si—NH—Si(R 4 ) 3 (II)
wherein each R 4 is a hydrocarbon group; or
3) a mixture of the silane of Formula (I) and the disilazane of Formula (II); and
c) incorporating a divalent metal into the precursor to form the metal-containing sorbent, wherein the divalent metal is incorporated in an amount equal to at least 5 weight percent based on the total weight of the sorbent.
15. The method of claim 14 , wherein the porous siliceous material has pores and wherein at least 50 volume percent of the pores are mesopores.