Fe(II)-substituted MEL-type zeolite, production method therefor and gas adsorbent including same, and nitric oxide and hydrocarbon removal method
The purpose of/problem addressed by the present invention is to provide: an Fe(II)-substituted MEL-type zeolite useful for the catalytic removal of a variety of gases; and a production method therefor. The SiO 2 /Al 2 O 3 ratio in this Fe(II)-substituted MEL-type zeolite is in the range of 10-30 inclusive. This Fe(II)-substituted MEL-type zeolite is obtained by being subjected to ionic exchange with Fe(II) ions. It is preferable that the Fe(II) loading amount be in the range of 0.001-0.4 mmol/g of the Fe(II)-substituted MEL-type zeolite. It is preferable that the Fe(II)-substituted MEL-type zeolite be produced using a method in which an MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-30 inclusive is dispersed in an Fe(II) water-soluble-compound aqueous solution, and then mixed and agitated to cause the MEL-type zeolite to carry Fe(II) ions.
1. An Fe(II)-substituted MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-30 inclusive and obtained by being subjected to ionic exchange with Fe(II) ions,
wherein the loading amount of Fe(II) is in the range of 0.001-0.4 mmol/g of the Fe(II)-substituted MEL-type zeolite.
2. The Fe(II)-substituted MEL-type zeolite according to claim 1 , wherein as the MEL-type zeolite before subjected to ionic exchange with Fe(II) ions, the MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-30 inclusive is used.
3. The Fe(II)-substituted MEL-type zeolite according to claim 1 , wherein a BET specific surface area ranges from 200 to 550 m 2 /g; a micropore specific surface area ranges from 180 to 450 m 2 /g; and a micropore volume ranges from 0.08 to 0.25 cm 3 /g.
4. A method for producing an Fe(II)-substituted MEL-type zeolite according to claim 1 , which comprises a step of dispersing an MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-30 inclusive in an Fe(II) water-soluble-compound aqueous solution and then mixing and agitating to cause the MEL-type zeolite to carry Fe(II) ions.
5. The method according to claim 4 , wherein 0.1 to 3 times the amount by mole of the Fe(II) of ascorbic acid is added to the aqueous solution upon the mixing and agitating.
6. A method for removing nitric oxide, which comprises bringing an Fe(II)-substituted MEL-type zeolite according to claim 1 into contact with nitric oxide or nitric oxide-containing gas to cause nitric oxide to be adsorbed on the Fe(II)-substituted MEL-type zeolite.
7. A method for removing hydrocarbons, which comprises bringing an Fe(II)-substituted MEL-type zeolite according to claim 1 into contact with hydrocarbons or hydrocarbon-containing gas to cause hydrocarbons to be adsorbed on the Fe(II)-substituted MEL-type zeolite.
8. The method according to claim 6 , wherein the nitric oxide-containing gas is an exhaust gas of low temperature at cold start of an internal combustion engine.
9. The method according to claim 7 , wherein the hydrocarbon-containing gas is an exhaust gas of low temperature at cold start of an internal combustion engine.
10. An Fe(II)-substituted MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-24 inclusive and obtained by being subjected to ionic exchange with Fe(II) ions, wherein the loading amount of Fe(II) is in the range of 0.001-0.4 mmol/g of the Fe(II)-substituted MEL-type zeolite.
11. The Fe(II)-substituted MEL-type zeolite according to claim 10 , wherein as the MEL-type zeolite before subjected to ionic exchange with Fe(II) ions, the MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-24 inclusive is used.
12. An Fe(II)-substituted MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-21 inclusive and obtained by being subjected to ionic exchange with Fe(II) ions, wherein the loading amount of Fe(II) is in the range of 0.001-0.4 mmol/g of the Fe(II)-substituted MEL-type zeolite.
13. The Fe(II)-substituted MEL-type zeolite according to claim 12 , wherein as the MEL-type zeolite before subjected to ionic exchange with Fe(II) ions, the MEL-type zeolite having an SiO 2 /Al 2 O 3 ratio in the range of 10-21 inclusive is used.
14. The Fe(II)-substituted MEL-type zeolite according to claim 10 , wherein a BET specific surface area ranges from 200 to 550 m 2 /g; a micropore specific surface area ranges from 180 to 450 m 2 /g; and a micropore volume ranges from 0.08 to 0.25 cm 3 /g.
15. The Fe(II)-substituted MEL-type zeolite according to claim 12 , wherein a BET specific surface area ranges from 200 to 550 m 2 /g; a micropore specific surface area ranges from 180 to 450 m 2 /g; and a micropore volume ranges from 0.08 to 0.25 cm 3 /g.
16. A method for removing nitric oxide, which comprises bringing an Fe(II)-substituted MEL-type zeolite according to claim 10 into contact with nitric oxide or nitric oxide-containing gas to cause nitric oxide to be adsorbed on the Fe(II)-substituted MEL-type zeolite.
17. A method for removing nitric oxide, which comprises bringing an Fe(II)-substituted MEL-type zeolite according to claim 12 into contact with nitric oxide or nitric oxide-containing gas to cause nitric oxide to be adsorbed on the Fe(II)-substituted MEL-type zeolite.
18. A method for removing hydrocarbons, which comprises bringing an Fe(II)-substituted MEL-type zeolite according to claim 10 into contact with hydrocarbons or hydrocarbon-containing gas to cause hydrocarbons to be adsorbed on the Fe(II)-substituted MEL-type zeolite.
19. A method for removing hydrocarbons, which comprises bringing an Fe(II)-substituted MEL-type zeolite according to claim 12 into contact with hydrocarbons or hydrocarbon-containing gas to cause hydrocarbons to be adsorbed on the Fe(II)-substituted MEL-type zeolite.