Sorbent and devices for capturing, stabilizing and recovering volatile and semi-volatile compounds
The present invention provides an improved sorbent and corresponding device(s) and uses thereof for the capture and stabilization of volatile organic compounds (VOC) or semi-volatile organic compounds (SVOC) from a gaseous atmosphere. The sorbent is capable of rapid and high uptake of one or more compounds and provides quantitative release (recovery) of the compound(s) when exposed to elevated temperature and/or organic solvent. Uses of particular improved grades of mesoporous silica are disclosed.
1. An explosive-containing sorbent, which is not detonable by fire, heat, friction or impact, wherein said sorbent excludes porous polymer and comprises one or more adsorbed explosive materials; and
a mesoporous silica of the MCM-41 type (hexagonal), wherein the mesoporous silica possesses a combination of two or more of the following physical properties:
Property
Linear formula
SiO 2 polymer
Pore structure
Hexagonal tubes
Pore size (diameter)
about 2 to about 30 nm
Pore volume
about 0.5 to about 2.0 cm 3 /g
Surface area
greater than about 600 m 2 /g
Channel wall thickness
about 1 to about 5 nm.
2. A method of converting a detonable explosive material into a non-detonable form, the method comprising adsorbing the explosive material onto a sorbent of mesoporous silica of the MCM-41 type (hexagonal), wherein the mesoporous silica possesses a combination of two or more of the following physical properties:
Property
Linear formula
SiO 2 polymer
Pore structure
Hexagonal tubes
Pore size (diameter)
about 2 to about 30 nm
Pore volume
about 0.5 to about 2.0 cm 3 /g
Surface area
greater than about 600 m 2 /g
Channel wall thickness
about 1 to about 5 nm.
and wherein said sorbent excludes porous polymer.
3. A method of neutralizing an explosive-containing sorbent, which is not detonable by fire, heat, friction or impact, said explosive-containing sorbent comprising sorbent and one or more explosive materials, the method comprising:
exposing the explosive-containing sorbent to an amount of one or more neutralizing agents for a period of at least 6 h.
4. The method of claim 3 , wherein:
a) the sorbent comprises a mesoporous silica of the MCM-41 type (hexagonal), wherein the mesoporous silica possesses a combination of two or more of the following physical properties:
Property
Linear formula
SiO 2 polymer
Pore structure
Hexagonal tubes
Pore size (diameter)
about 2 to about 30 nm
Pore volume
about 0.5 to about 2.0 cm 3 /g
Surface area
greater than about 600 m 2 /g
Channel wall thickness
about 1 to about 5 nm;
b) the exposing is conducted in the absence of a fluid;
c) said neutralizing is conducted without detonation of the one or more explosive materials;
d) said one or more types of neutralizing agents are selected from the group consisting of at least one organic acid, at least one surfactant, at least one sulfur-containing inorganic salt, at least one antioxidant, at least one oxidizing agent, at least one reducing agent, and combinations thereof
e) a combination of any two or more of the above.
5. The sorbent of claim 1 , wherein the mesoporous silica comprises:
a) at least one non-functionalized mesoporous silica; b) at least one functionalized mesoporous silica; or c) a combination of one or more non-functionalized mesoporous silica and one or more functionalized mesoporous silica.
6. The sorbent of claim 5 , wherein the weight ratio of non-functionalized mesoporous silica to functionalized mesoporous silica range from about 1:100 to about 100:1.
7. The sorbent of claim 5 , wherein the sorbent has been functionalized with one or more adsorption modifier functional groups that improve in at least one aspect the adsorption of particular VOC or SVOC.
8. The sorbent of claim 7 , wherein: a) the one or more adsorption modifier functional groups are covalently bound to the porous medium; b) the one or more adsorption modifier functional groups are non-covalently bound to the porous medium; c) the mass content of functional groups in the porous medium as determined by thermogravimetric analysis is in the range of 20-25%; or d) a combination of any two or more thereof.
9. The sorbent of claim 1 , wherein the sorbent comprises silane-functionalized mesoporous silica.
10. The sorbent of claim 9 , wherein the silane functionalized mesoporous silica has been functionalized by treating unfunctionalized mesoporous silica with a trialkoxyalkylsilane (R 1 Si(OR 2 ) 3 ), wherein:
R 1 is selected from the group consisting of aromatic group, alkyl group, oxygen-containing alkyl groups, sulfur-containing alkyl groups, nitrogen-containing alkyl groups, phenyl, biphenyl, (C1-C8)-alkyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decanyl, undecanyl, methoxytriethyleneoxypropyl, alkoxyalkyleneoxyalkyl, haloalkyl, halo-(C1-C8)-alkyl, aminoalkyl, alkoxyalkyl, polyaromatic, toluyl, fluoroalkyls, fluroaromatics, and their combinations; and
R 2 is selected from the group consisting of alkyl, C1-C12-alkyl, with methyl, ethyl, and propyl being preferred, thereby forming a silane-functionalized mesoporous silica comprising plural silane groups R 1 covalently bound to oxygen molecules of the mesoporous silica.
11. The sorbent of claim 9 , wherein the silane functionalized mesoporous silica comprises functional groups with a chemical formula defined as —Si(R 1 )(OR 2 ) n —O m —, wherein:
R 1 is selected from the group consisting of aromatic group, alkyl group, oxygen-containing alkyl group, phenyl, biphenyl, C1-C8-alkyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decanyl, undecanyl, methoxytriethyleneoxypropyl, alkoxyalkyleneoxyalkyl, haloalkyl, alkoxyalkyl, polyaromatic, and toluyl;
R 2 is selected from the group consisting of alkyl, C1-C12-alkyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decanyl, and undecanyl,
thereby forming a silane-functionalized mesoporous silica comprising plural silane groups R 1 Si-covalently bound to oxygen molecules of the mesoporous silica; and
wherein n is 0, 1 or 2, and m is 2, 1, or 0, respectively.
12. The sorbent of claim 1 , wherein, the sorbent releases at least 75 wt % of adsorbed VOC or SVOC when the sorbent is exposed to heat or organic solvent.
13. The sorbent of claim 1 , wherein the sorbent releases less than 25% of VOC or SVOC during storage at ambient temperature for a period of at least 1 week.
14. An explosive-containing sorbent, which is not detonable by fire, heat, friction or impact, comprising:
one or more explosive materials; and
a mesoporous silica of the MCM-41 type (hexagonal), wherein the mesoporous silica possesses a combination of two or more of the following physical properties:
Property
Linear formula
SiO 2 polymer
Pore structure
Hexagonal tubes
Pore size (diameter)
about 2 to about 30 nm
Pore volume
about 0.5 to about 2.0 cm 3 /g
Surface area
greater than about 600 m 2 /g
Channel wall thickness
about 1 to about 5 nm
wherein said mesoporous silica comprises silane-functionalized mesoporous silica; and wherein said sorbent excludes porous polymer.
15. The sorbent of claim 14 , wherein the silane functionalized mesoporous silica has been functionalized by treating unfunctionalized mesoporous silica with a trialkoxyalkylsilane Si(OR 2 ) 3 ), wherein:
R 1 is selected from the group consisting of aromatic group, alkyl group, oxygen-containing alkyl groups, sulfur-containing alkyl groups, nitrogen-containing alkyl groups, phenyl, biphenyl, (C1-C8)-alkyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decanyl, undecanyl, methoxytriethyleneoxypropyl, alkoxyalkyleneoxyalkyl, haloalkyl, halo-(C1-C8)-alkyl, aminoalkyl, alkoxyalkyl, polyaromatic, toluyl, fluoroalkyls, fluroaromatics, and their combinations; and
R 2 is selected from the group consisting of alkyl, C1-C12-alkyl, with methyl, ethyl, and propyl being preferred, thereby forming a silane-functionalized mesoporous silica comprising plural silane groups R 1 Si— covalently bound to oxygen molecules of the mesoporous silica.
16. The sorbent of claim 14 , wherein the silane functionalized mesoporous silica comprises functional groups with a chemical formula defined as —Si(R 1 )(OR 2 ) n —O m —, wherein:
R 1 is selected from the group consisting of aromatic group, alkyl group, oxygen-containing alkyl group, phenyl, biphenyl, C1-C8-alkyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decanyl, undecanyl, methoxytriethyleneoxypropyl, alkoxyalkyleneoxyalkyl, haloalkyl, alkoxyalkyl, polyaromatic, and toluyl;
R 2 is selected from the group consisting of alkyl, C1-C12-alkyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decanyl, and undecanyl,
thereby forming a silane-functionalized mesoporous silica comprising plural silane groups R 1 Si-covalently bound to oxygen molecules of the mesoporous silica; and
wherein n is 0, 1 or 2, and m is 2, 1, or 0, respectively.
17. The sorbent of claim 14 , wherein, the sorbent releases at least 75 wt % of adsorbed VOC or SVOC when the sorbent is exposed to heat or organic solvent.
18. The sorbent of claim 14 , wherein the sorbent releases less than 25% of VOC or SVOC during storage at ambient temperature for a period of at least 1 week.
19. The explosive-containing sorbent of claim 1 , wherein the mesoporous silica possesses a combination of the following physical properties:
Property
Linear formula
SiO 2 polymer
Pore structure
Hexagonal tubes
Pore size (diameter)
about 5 to about 10 nm
Pore volume
about 0.5 to about 0.7 cm 3 /g
Surface area
about 600 up to about 900
m 2 /g
Channel wall thickness
about 2 to about 5 nm.
20. The method of claim 2 , wherein the mesoporous silica possesses a combination of the following physical properties:
Property
Linear formula
SiO 2 polymer
Pore structure
Hexagonal tubes
Pore size (diameter)
about 5 to about 10 nm
Pore volume
about 0.5 to about 0.7 cm 3 /g
Surface area
about 600 up to about 900
m 2 /g
Channel wall thickness
about 2 to about 5 nm.
21. The method of claim 4 , wherein the mesoporous silica possesses a combination of the following physical properties:
Property
Linear formula
SiO 2 polymer
Pore structure
Hexagonal tubes
Pore size (diameter)
about 5 to about 10 nm
Pore volume
about 0.5 to about 0.7 cm 3 /g
Surface area
about 600 up to about 900
m 2 /g
Channel wall thickness
about 2 to about 5 nm.