DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Claims 23–25 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected method, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on Dec. 17, 2025.
Claim Objections
Claims 2–18 are objected because the preamble “a gas filter according to claim 1” is objected because it should be “the gas filter according to claim 1.”
Claim 21 is objected because the term “An active element suitable for use in the gas filter in accordance with claim 1” should be “The active element suitable for use in the gas filter in accordance with claim 1.”
Additionally, claim 22 “an active element according to claim 21” is objected because it should be “the active element according to claim 21.”
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 12, 16–18, 22 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 12 is indefinite because in contains both narrow and broad range, it is unclear if the narrow range meant to further limit.
Claim 15 is indefinite because it is unclear if the example in parenthesis meant to further limit.
Claim 16 is indefinite because it is unclear the limitation after “optionally” is a required limitation of the claim. Additionally, it is unclear if the limitation of “e.g. alpha alumina powder, Al2O3) further limits the claim.
Claim 17 is indefinite because it is unclear if the recited “a matrix material” “a CO2 sorbent” and “water” in claim 17 is the same as those recited in claim 1. Claim 21 is rejected for the same issue as claim 17.
Claim 18 is indefinite because it is unclear if the limitation after “for example” means to further limit.
Claim 22 is indefinite because it is unclear what is considered “further characterized.”
Claim Rejections - 35 USC § 112(d)
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claims 21–22 are rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends. Here Claim 21 does not further limit, because the limitation is already recited in claim 1, and claim 21 depends on claim 1.
Claim 22 is rejected because it depends on claim 21.
Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
Claim Rejections - 35 USC § 102(a)(1)
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1–7, 12, 14–22 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Liu et al., CN 1795979 A (“Liu”)1.
Regarding claim 1:
Liu discloses that a gas filter (Liu’s dry regenerated carbon dioxide adsorbent, Liu p. 2) comprising an active element (Liu discloses as solid sorbent, Liu p. 5) and a housing structure (Liu discloses as “fluid bed”, Liu p. 5) for said active element,
said housing structure comprising a gas inlet and a gas outlet (Liu discloses its regenerable adsorbent captures carbon dioxide before discharging power plant exhaust, and therefore, where Liu’s exhaust enters Liu’s fluid bed that accommodates the regenerable adsorbent is the claimed “gas inlet” and where cleaned exhaust exits Liu’s fluid bed is the claimed “gas outlet”, Liu p. 4),
said active element comprising or consisting of: a matrix material (Liu discloses as “carrier”, Liu p. 5); a CO2 sorbent (Liu’s active component, Liu p. 5); and water (Liu discloses its active component react with CO2 and water, and therefore, water is necessary for the carbon dioxide adsorber to be “active” and therefore water is an essential component of the “active element” Liu p. 5),
wherein at least some of the CO2 sorbent is embedded within the matrix material (Liu discloses its carrier could be a molecular sieve, Liu p. 3, molecular sieve is a microporous material with interconnected pores, when serves as a carrier for CO2 sorbent, CO2 sorbent would necessarily be accommodated in the porous structure, and therefore read on the term “embed”).
Regarding claim 2:
Liu discloses that a gas filter according to claim 1, wherein the matrix material comprises, consists of, or consists essentially of a ceramic material and/or a polymer (Liu discloses its carrier could be ceramic, Liu p. 3).
Regarding claim 3:
Liu discloses that a gas filter according to claim 1, wherein the matrix material is a ceramic material and said ceramic material comprises an inorganic mineral (Liu discloses its ceramic could be silica, Liu p. 4, Silica is an inorganic mineral).
Regarding claim 4:
Liu discloses that a gas filter according to claim 2, wherein the ceramic material comprises a clay material (Liu discloses an inorganic binder would be added to the fluidized bed to imparting strength, and such inorganic binder could be a clay material, Liu p. 4, the inorganic binder located between the sorbent and carrier is considered part of the carrier, and therefore, reads on “the ceramic material comprises a clay material”).
Regarding claim 5:
Liu discloses that a gas filter according to claim 4, wherein the clay material is selected from any one or more of kaolinite, montmorillonite-smectite, ilite, chlorite clay or clays (Liu discloses that the clay could be Kaolin, Liu p. 4).
Regarding claim 6:
Liu discloses that a gas filter according to claim 4, wherein the clay material is selected from any one or more of clinoptalite, palygorskite, attapulgite, bentonite (Liu discloses its clay could be bentonite, Liu p. 4).
Regarding claim 7:
Liu discloses that a gas filter according to claim 1, and wherein the matrix material comprises, consists of, or consists essentially of a polymer (as discussed in claim 4, binder located between sorbent and carrier to improve strength is considered part of the carrier, and Liu discloses its binder could be polydifluoroethylene, which is polymer, Liu p. 6).
Regarding claim 12:
Liu discloses that a gas filter according to claim 1, wherein the CO2 sorbent is selected from an alkali metal carbonate, for example one or more of K2C03, Na2CO3, Li2CO3 (Liu discloses the sorbent material can be alkali earth metal carbonate, Liu p. 4).
Regarding claim 14:
Liu discloses that a gas filter according to claim 1, wherein at least some of the water or all of the water is provided by an additional solid material (Liu discloses its adsorbent has hydrophilic and comprising silica dioxide and alumina, which are known desiccant that would contain water when exposed to water, and Liu also discloses its sorbent is mixed with water, Liu p. 4, it is therefore understood that some of the water is provided by an additional solid material silica dioxide).
Regarding claim 15:
Liu discloses that a gas filter according to claim 14, wherein the additional solid material is particulate and is selected from one or more of aluminum oxide, zeolite, silicate, (e.g. silica gel), metal organic framework (MOF), clay, (e.g. kaolinite) (Liu discloses alumina, which is aluminum oxide, Liu p. 4).
Regarding claim 16:
Liu discloses that a gas filter according to claim 14, wherein the additional solid material is selected from particulate aluminium oxide (e.g. alpha alumina powder, A1203) and optionally the particle size of the aluminium oxide is less than 50 pm (Liu discloses aluminum oxide powder, Liu p. 10).
Regarding claim 17:
Liu discloses that a gas filter according to claim 1, wherein the active element comprises a combination of (i) a matrix material which is a ceramic material (Liu p. 4), a CO2 sorbent (Liu discloses as alkaline earth metal carbonate and so on, Liu p. 4), and water wherein at least some of the CO2 sorbent is embedded within the matrix (Liu discloses a step where water is added to the sorbent, and Liu discloses its carrier and its active substance has the same structure, Liu p. 11, Liu discloses its active substance is porous, which means the carrier is porous to accommodate the sorbent, which means the sorbent is embedded within the carrier),
plus (ii) a matrix material which is a polymer (Liu discloses an inorganic/organic binder could be added to the fluidized bed to imparting strength, and such inorganic binder could be a clay material, Liu p. 4, the binder located between the sorbent and carrier is considered part of the carrier, and Liu discloses such binder could be PVA, Liu p. 6; PVA is polymer, and since binder between the carrier and adsorbent is considered part of the carrier, the matrix material therefore comprises a polymer of PVA),
a CO2 sorbent (see Liu p. 4), and water wherein at least some of the CO2 sorbent is embedded within the matrix (PVA has a porous structure, and since Liu discloses its process involves mixing with water, at least some of the sorbent has to be embedded within the PVA polymer to ensure a strengthened connection with binder PVA).
Regarding claim 18:
Liu discloses that a gas filter according to claim 1, wherein the CO2 sorbent is present in the form of a precursor thereof, for example at least one bicarbonate (Liu discloses bicarbonate, Liu p. 12).
Regarding claim 19:
Liu discloses that a method of removing carbon dioxide from a gas stream comprising passing the gas stream through the gas filter in accordance with claim 1 (Liu’s process of CO2 capture in combustion gas flow using the sorbent particles in fluidized bed, Liu p. 12).
Regarding claim 20:
Liu discloses that a method according to claim 19, wherein the gas filter or active matrix is heated in order to (re)generate the CO2 sorbent (Liu discloses regenerating by heat, ps. 2 and 12).
Regarding claim 21:
Liu discloses that an active element suitable for use in the gas filter in accordance with claim 1, wherein the active element (Liu discloses as solid sorbent, Liu p. 5) comprises or consists of: a matrix material (Liu discloses as “carrier”, Liu p. 5); a CO2 sorbent (Liu’s active component, Liu p. 5); and water (Liu discloses its active component react with CO2 and water, and therefore, water is necessary for the carbon dioxide adsorber to be “active” and therefore water is an essential component of the “active element” Liu p. 5),
wherein at least some of the CO2 sorbent is embedded within the matrix material (Liu discloses its carrier could be a molecular sieve, Liu p. 3, molecular sieve is a microporous material with interconnected pores, when serves as a carrier for CO2 sorbent, CO2 sorbent would necessarily be accommodated in the porous structure, and therefore read on the term “embed”).
Regarding claim 22:
Liu discloses that an active element according to claim 21, wherein the active element is further characterized (see mapping of claim 2, which qualifies as a further characterization).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
The claims are rejected as follows:
Claims 8–10 are rejected under 35 U.S.C. 103 as being unpatentable over Liu in view of Buelow et al., US 2013/0095996 A1 (“Buelow”).
Regarding claim 8:
Liu does not disclose that a gas filter according to claim 7, wherein the polymer is a foamed polymer.
In the analogous art of carbon dioxide sorbent carrier, Buelow discloses a polyurethane foam used as a sorbent carrier, Buelow [0013], [0059]. Additionally, Buelow discloses ceramic structure as another alternative as a sorbent carrier, Buelow [0059]. It would therefore have been obvious for one ordinary skill in the art at the time of filing for Liu’s matrix material to be made of PU because PU is listed by in the CO2 sorbent carrier art as an alternative in addition to clay material to act as CO2 sorbent carrier. A person of ordinary skill in the art would be motivated to use PU because compared to clay PU is a lighter material.
Regarding claim 9:
Liu does not disclose a gas filter according to claim 7, wherein the polymer comprises one or more, or any combination of polyurethane (PU), poly(vinylpyrrolidone) (PVP), polyimide (PI), polymers of intrinsic microporosity (PIMs), polyvinylidene difluoride (PVDF), polyethersulfone (PES), cellulose or bio-degradable polymers such as polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA).
However, as discussed in claim 8, it would therefore have been obvious for one ordinary skill in the art at the time of filing for Liu’s matrix material to be made of PU because PU is listed by in the CO2 sorbent carrier art as an alternative in additional to clay material to act as CO2 sorbent carrier. A person of ordinary skill in the art would be motivated to use PU because compared to clay PU is a lighter material. With such modification, Liu as modified by Buelow teaches the claimed limitation because the polymer comprises PU.
Regarding claim 10:
Liu does not disclose that a gas filter according to claim 7, wherein the polymer comprises, or consists of, or consists essentially of a polyimide.
In the analogous art of carbon dioxide sorbent carrier, Buelow discloses polyimide used as a sorbent carrier, Buelow [0074]. Additionally, Buelow discloses ceramic structure as another alternative as a sorbent carrier, Buelow [0059]. It would therefore have been obvious for one ordinary skill in the art at the time of filing for Liu’s matrix material to be made of polyimide because polyimide is listed by in the CO2 sorbent carrier art as an alternative in addition to clay material to act as CO2 sorbent carrier. A person of ordinary skill in the art would be motivated to use polyimide because compared to clay polyimide is a lighter material.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Liu in view of Gebald et al., US 2021/0187480 A1 (“Gebald”).
Regarding claim 11:
Liu does not disclose that a gas filter according to claim 1, wherein the matrix material comprises mesopores and/or macropores.
In the analogous art of CO2 sorbent carrier, Gebald discloses that the CO2 adsorption capacities increase with increasing mesopore surface of the support, Gebald [0023]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to include mesopores in Liu’s matrix material for an increased adsorption capacity.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Liu.
Regarding claim 13:
Liu does not explicitly disclose that a gas filter according to claim 1, wherein the water is embedded within the matrix material.
However, Liu discloses that the adsorbent material is uniformly distributed in the carrier for an improved reactivity, and the adsorbent has a required water content, Liu p. 4. It would therefore have been obvious for some of the water to be embedded within them matrix material because the adsorbent with a required water content has to be uniformly distributed in a porous carrier, which would necessarily require some of the adsorbent (with water content) to be embedded within the carrier.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to QIANPING HE whose telephone number is (571)272-8385. The examiner can normally be reached on 7:30-5:00 M-F.
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/Qianping He/Examiner, Art Unit 1776
1 Liu’s original document is the 20-page FOR dated Jun. 05, 2023 and machine translation is the 14-page FOR dated Oct. 28, 2025.